Abstract:
The averaged pulse energy (J) of a Pulsed Type Laser Source can be measured by several types of commercial laser energy meters, such as pyroelectric detector or thermopile sensor, the spectral responsivity and the time/frequency related response properties of which are compatible with those of the Pulsed Type Laser Source. These Commercial Laser Energy Meters, regardless of sensor/detector type, should be calibrated against the working standards calibrated in a national (or an international) traceability chain relying on primary standards on the highest level having the lowest uncertainty in realizations of the fundamental SI units. FCIS based-LEMCS designed in this invention accomplishes both of the above proficiencies of measuring the averaged pulse energy of the Pulsed Type Laser Source and calibrating the Commercial Laser Energy Meters, which are traceably to primary level standards. FCIS based-LEMCS contains an integrating sphere having a novel port and an interior design and a series of mechanical choppers having separate Duty Cycles, each of which is rotated by an electrical motor in FCIS based-LEMCS, used for generating a chopped type laser, called as Chopped Type Laser Source, in order to provide the reference and averaged pulse energy for traceable calibration of Commercial Laser Energy Meters. With this invention, in addition to generating the reference and averaged pulse energy to be used during the calibration of Commercial Laser Energy Meters to be performed by means of FCIS based-LEMCS, the peak pulse energies of the Pulsed Type Laser Source and the Chopped Type Laser Source, which is a strict part of FCIS based-LEMS and which is used for producing the reference averaged pulse energy in the calibration of Commercial Laser Energy Meters, are also measured by FCIS based-LEMCS, traceable to Electrical Substitution Cryogenic Radiometer (ESCR) in primary optical watt scale (W), to  133 Cs (or  87 Rb) Atomic Frequency Standard in time scale t (s), and to direct current unit (A) realized with Quantum Hall—primary resistance standard (ohm) and DC Josephson primary voltage standard (V). With this configuration presented as a preferred embodiment, the averaged pulse energy measurements are performed and achieved for a range extending from 16.5 p J to 100 mJ.

Description:
FIELD 
       [0001]    The present invention is related to a Fiber Coupled Integrating Sphere (FOS) Based-Laser energy Meter and Calibration System (FCIS based-LEMCS), designed for both measuring the averaged pulse energy of a Pulsed Type Laser Source generating infinite laser pulse train in time domain, and calibrating Commercial Laser Energy Meters, which is fully traceable to Primary Level Standards, together with new calibration method. 
       BACKGROUND 
       [0002]    Laser, an acronym, means amplification of amplitude-, frequency- and phase-coherent electromagnetic waves generated by a suitable pumping process inside a closed region composed of a mixture of relevant radiating atoms and molecules, the energy levels of which fully conforms to a stimulated emission created by a feedback of some portion of the coherent electromagnetic wave at the output port of the region. 
         [0003]    The areas of use of lasers get very diverse along with the increasing in the developments of the design and manufacturing of high technology products. If a categorization according to priorities of using the highest technology in industrial products is made, it is seen that health and war technology equipments are more dominant over the other industry sectors. The lasers can have continuous wave (CW) mode lasing and/or pulsed-mode lasing and have conspicuous and effective characteristics such as lethal or non lethal effects, physiological, psychological or directly physical effect depending on the energy transferred into any target in modern war and health equipments. In order to make exact and correct evaluations about the resultant effects of any laser source on any target, it seems that it is an unavoidable approach to make spectral power distribution, total power and energy measurements of the relevant laser source in addition to the determination of surface absorption/reflection, structural and atomic/molecular bonding characteristics of the target. 
         [0004]    The spectral power distribution (W/nm) and the total power (W) carry a significant meaning for a CW mode/regime laser source because the knowledge of total power of a CW laser is enough to calculate the total exposure over time t (s) for surface of any relevant target in (j) and (j/cm 2 ), energy density, by taking the target absorptiveness into account. Differently from the measurement of total power of CW laser in W, the measurement of laser energy (J) per pulse for a Pulsed Type Laser Source in time domain conveys a significant meaning, because the exposure of the Pulsed Type Laser Source depends on pulse width (PW) and peak power P 0  of the Pulsed Type Laser Source, considering surface absorption/reflection, structural and atomic/molecular bonding properties of the target 
         [0005]    NOTE: The term “Chopped Type Laser Source” in the invention means the modulated laser source generated by chopping CW Gaussian Laser Beams of CW Laser Source(s) mechanically by means of the group of the circular and metallic choppers, which is strict a part of FCIS based-LEMCS invented. The term “Pulsed Type Laser Source” in the invention means any other laser source which is different from the “Chopped Type Laser Source”, and which is not a part of FCIS based-LEMCS invented. Nevertheless, both “Chopped Type Laser Source” and “Pulsed Type Laser Source” in the invention produce laser pulses, both of which have Gaussian beam profile, as infinite pulse train in time domain and finally, the term “Gaussian Laser Beam” used in the invention means diffraction limited—transverse electromagnetic mode having the lowest order (TEM 00 ). 
         [0006]    The transferred energy into the target by a laser source regardless of CW or pulsed type results in a temperature increase in limited volume of the target, depending on the heat capacity, mass and the initial temperature of the relevant volume of the target. Detecting the temperature increase of the relevant volume of the target resulted from the energy of the laser source can be made via conventional semiconductor type or metal/metal contact type temperature sensors. To gain signal to noise ratio (SNR) of detection system, which is one of the most important parameter increasing the measurement uncertainty, the separation of the temperature variation caused by energy transfer requires to be extended. The way to extend the separation between the initial temperature and the final temperature caused by laser source energy is to reduce the heat capacity (specific heat) of the target which is accomplished by reducing the initial temperature of the target down to cryogenic level, relying on Bose-Einstein approach. Reducing the initial temperature of the target also minimizes the atomic and molecular vibrations. According to Bose-Einstein statistic for the canonical ensemble, the heat capacity (specific heat) of a solid target reduces exponentially at cryogenic levels of temperature and this physical phenomenon expands the separation between the final and the initial temperature of the target, which expresses an absorbing cavity in a Cryogenic Radiometer (CR) and finally a calorimetric measurement for absolute optical power measurement and also optical energy measurement. 
         [0007]    By considering the above summary, the traceable measurements of the laser energy meters and their traceable calibrations can be carried out by measuring the temperature difference (K) between the final and the initial temperature of the target along with inclusion of mass (kg) and the specific heat (J/(kg K)), which is a measureable quantity, in the calculations, bearing in mind that the time constant of the target (or the absorbing cavity). In a CR, the specific heat of the absorbing cavity for the electrical watt (A·V=W) applied within Δt (s) time interval is obtained as a ratio and it is called as thermal coefficient in (W/K), also generating (J/K). In this traceability stage, it is seen that temperature (K), direct current (A) and direct voltage (V) together with traceable time (s) measurement necessary to define the time constant (s) of the target (or the absorbing cavity) and time interval Δt (s) of the electrical power applied to the absorbing cavity should be wholly traceable to primary standards. As a result, the averaged pulse energy of a Pulsed Type Laser Source/Chopped Type Laser Source can be derived by calorimetric methods with traceability of temperature (K), direct current (A), direct voltage (V), and time (s). 
         [0008]    Under the illumination of the above briefing related to the traceability chain of optical power and energy, it is understood that we need an optical power measurement in (W) and a time measurement in (s) for realization of the averaged pulse energy (J) of any Pulsed Type Laser Source. The mathematical basis belonging to deriving the averaged pulse energy of the Pulsed Type Laser Source is given by taking the laser pulses having a pulse width of PW (s) and a period of T (s), the peak power of which is P 0  (W), as an infinite pulse training time domain. Referring to the periodic pulse shape of Pulsed Type Laser Source in the style of an infinite pulse wave train, the function of output power of the Pulsed Type Laser Source for a period of T (s) is defined as P(t) in Eq. (1): 
         [0009]               (W) (1) 
         [0010]    And P(t) is a periodical function, as an infinite laser pulse train in time domain, P(t)=P(t+T). Pulse energy of the single pulse of Pulsed Type Laser Source, PE (J); 
         [0011]               (J) (2) 
         [0012]    The average power of the Pulsed Type Laser Source, P av ; 
         [0013]               (W) (3) 
         [0014]    If the integral is written in the most general form and in the averaged terms by taking the Duty Cycle into account, Eq. (4) is obtained: 
         [0015]               (W) (4) 
         [0016]               (5) 
         [0017]               (W) (6) 
         [0018]    Where the averaged pulse width is PW  av  and the averaged dead time is DT av  in an averaged repetition period T av  for an infinite laser pulse train generated by Pulsed Type Laser Source. The averaged pulse energy of Pulsed Type Laser Source is obtained by multiplying N with PE av . N is the pulse number and is equal to 1 for periodic and infinite pulse train in time domain. 
         [0019]    Eq. (4) and (6) give us a very useful approach to derive the averaged pulse energy PE av  of Pulsed Type Laser Source. If repetition period T and the averaged optical power P av  of Pulsed Type Laser Source are measured, the averaged pulse energy can easily be calculated. These measurements of the averaged repetition period T av  and the averaged optical power P av  should be performed traceable to primary level standards, which are  133 Cs (or  87 Rb) Atomic Frequency Standard in time scale (s), and optical power transfer standard calibrated against absolute optical power measurement system called CR in optical power scale (W) [1 and 2], and an electrometer in direct current scale (A) traceable to Quantum Hall System, and DC Josephson System. The precise measurements of T av  and P av  traceable the primary level standards exhibits a process without measuring the temperature change caused by the averaged pulse energy of a Pulsed Type Laser Source. The most uncertainty contribution of the calorimetric measurements of the averaged pulse energy is resulted from the determination time constant of an absorbing surface (target) and so the pulse and the modulation response of the absorbing cavity (target). In addition to the elimination of time constant of FCIS in time/frequency related measurements in the invention, the new configuration of the integrating sphere invented, called as FCIS, enables the user positioning the laser beam having a Gaussian profile on the same optical axis with respect to the entrance port for every calibration process so the reproducibility of the calibration and the measurement processes are increased with the new configuration of FCIS. 
         [0020]    Photovoltaic type photodiodes generate an integrated photocurrent as response of the optical flux falling on the sensitive surfaces, corresponding to average optical power of the incident optical flux. This is also valid for the ultra fast photodiodes having very fast impulse response, like positive-intrinsic-negative (PIN) photodiodes as well as avalanched type photodiodes supplied with a reversed voltage bias which reduces the diffusion capacity of the photodiode, still used in optical time domain reflectometer instruments. The integrated photocurrent is also generated for the relatively small portion of light flux within optical pulses having ultra short time intervals, such as Δt≅20×10 −12  s. 
         [0021]    The parameters to be measured to determine the averaged pulse energy PE av  of the Pulsed Type Laser Source in Eq. (6) are averaged repetition period T av , number of pulses N having a varying pulse width PW, and average power P av , corresponding to an average photocurrent I av  generated by the First Photodiode, which is InGaAs_1 for the apparatus designed as one embodiment in the invention. Eq. (6) can be re-written as Eq. (7) by considering the spectral responsivity of the First Photodiode in order to obtain the averaged pulse energy of Pulsed Type Laser Source in  FIG. 1  and  FIG. 2 . 
         [0022]               (W) (7) 
         [0023]    Where is the spectral power responsivity of FCIS, to which the First Photodiode is mounted, in A/W. As stated above, I av  is measured by the First Photodiode placed orthogonally with respect to laser entrance port of FCIS., is the periodic pulse type photocurrent, generated by P(t). I av  is the time average of I ph (t). T av  (and/or f av ) is measured by using a second photodiode mounted on an internal steel hemisphere, which is placed on directly opposite Gaussian laser beam entrance port of FCIS of FCIS based-LEMCS. For single pulse having a unit amplitude, rect(t) function is defined as in Eq. (8). 
         [0024]               (8) 
         [0025]    This definition of a single pulse given in Eq. (8) will be useful for the description of the pulse response of the First Photodiode and for the description of use of a second photodiode, which is different from the First Photodiode, and which has a relatively small time constant, to carry out time/frequency related measurements in Eq. (7). in Eq. (7) is obtained by calibrating FCIS based-LEMCS against the Optical Power Transfer Standard, which is an InGaAs based spectral on sphere radiometer directly and which is absolutely calibrated against Cryogenic Radiometer (CR) in this invention. Another alternative process of deriving the of the First Photodiode can be performed with a relatively higher uncertainty arising from the surface non uniformity by referencing a flat spectral response Electrically Calibrated Pyroelectric Radiometer (ECPR), traceable to CR. in such a way that the whole spectra of 900 nm to 1650 nm of the First Photodiode is covered. 
         [0026]    NOTE: The use of different type of Optical Power Transfer Standard doesn&#39;t disturb the philosophy of the invention because PUS based-LEMCS is one embodiment. 
         [0027]    According to Eq. (7), if I av , T av , and are measured, the specified and averaged pulse energy PE av of the Pulsed Type Laser Source can be calculated with an expanded uncertainty by taking the related partial derivations of I av , T av  and into the calculations. 
         [0028]    The Second Photodiode, which is InGaAs_2 in the invention as one embodiment, is assembled with a first multimode (MM) patch cord. FC/PC connector end of the first multimode (MM) patch cord is combined to a Mechanical Attenuator and the HMS connector end of the first MM fiber patch cord having a Zr ferrule is mounted on the center of the inner wall of an internal steel hemisphere, which is placed inside FCIS, which has a smaller diameter than that of FCIS. The Second Photodiode combined with the hemisphere through a second MM patch cord, the Mechanical Attenuator, and the first MM patch cord having ceramic and Zr ferrules is used for the time measurements such as averaged repetition period T av  and averaged repetition frequency f av  in Eq. (7), cutoff limit is 6 GHz. The second use purpose of the Second Photodiode is to coincide optical axes of FCIS and Pulsed Type Laser Source, Chopped Type Laser Source, and CW Laser Source. The Internal Steel Hemisphere is made from stainless steel and is assembled with a Zr ferrule of the first MM optical fiber patch cord. The Internal Steel Hemisphere is so settled inside FCIS that Gaussian laser beam entrance port of FCIS of FCIS based-LEMCS sees directly the center of the Internal Steel Hemisphere, at the center of which Zr ferrule of HMS connector end of the first MM optical fiber patch cord is mounted back 0.2 mm from the inner surface. The placement of a internal steel hemisphere together with Zr ferrule of HMS connector end of the first MM optical fiber patch cord is one of the important points of this invention. 
         [0029]    The practical way to search the frequency response of any electronic device, such as a pin photodiode in this invention, is to apply a pulse having a varying pulse width and a varying period to the electronic device. According to the Fourier transformation between time and frequency domains, as long as the pulse width PW is made relatively narrow, it is seen that the frequency content of the pulse increases. As a result, an ideal δ(t)-impulse function in time domain covers a frequency range from zero to infinite theoretically. The periodic optical pulses P(t) generated by the Pulsed Type Laser Source, the pulse width PW of which are adjustable, can be defined as a sum of odd (sinus) harmonics in Fourier series, and they have the decreasing amplitude with a DC component, the period of which is T (s), matching the repetition frequency f (Hz). Correspondingly, the modulation frequency response of FCIS is obtained the sum of all the responses of FCIS through the First Photodiode against the each frequency component obtained from the Fourier series. When the frequency content of Fourier Series of a periodic pulse train repeated within repetition period T is seen, the first term, which has the highest amplitude, is f (Hz), which is exactly the same as the repetition frequency of the Pulsed Type Laser Source. The successive frequency terms of sinus are lined up to 2f, 3f, 4f, . . . , nf, where n is the number of the summed frequency components, with the decreasing amplitude. It should be noted that making the pulse width PW in time domain be narrow increases the frequency contents. Therefore the pulse response characteristics and the modulation frequency response characteristics of the First Photodiode of FCIS, which is used to measure the averaged photocurrent I av  proportional to the averaged optical power P av , are presented together herein. 
         [0030]    It is pointed out that FCIS based-LEMCS and the method described in the invention can operate up to a repetition rate of 1 MHz which is the cutoff limit of the First Photodiode. In order to use FCIS based-LEMCS correctly and properly in measuring the average optical power P av . FCIS based-LEMS should be held within the frequency range in which the First Photodiode of FCIS based-LEMCS has a flat frequency response. If the repetition frequency is too high the First Photodiode to catch, which corresponds to being too faster rising and falling edge times, and too narrower pulse widths and dead times, it is impossible to convert the average optical power of such an infinite pulse train of Pulsed Type Laser Source having a peak power of P 0  into the average photocurrent. This is an inherent behavior for the photodiodes as well as the electronic circuit exhibiting low pass filter behavior. 
         [0031]    The First Photodiode behaves as a RC low pass filter for the increasing modulation frequencies resulted from the equivalent circuits composed of the total of junction capacitance (C j  ) and stray capacitance (C s ) of the First Photodiode, which acts as in reversed bias condition when light flux falls onto the sensitive surface of the First Photodiode. Correspondingly, diffusion capacity of the First Photodiode, which describes the rearrangement of the minority carriers within the depletion region under the forward bias, is not considered in this equivalent circuit. The equivalent circuit of the First Photodiode in FCIS of FCIS based-LEMCS is shown in  FIG. 3 . Resultantly, the equivalent capacitance is C eq =C j +C s ≅200 pF, and at zero bias, C j ≅20 pF at 25° C. The equivalent resistance of the First Photodiode consists of parallel shunt resistance (R sh ), serial resistance of bulk semiconductor (R s ), and parallel input resistance of the following current to voltage amplifier (R i ), directly corresponding to the electrometer used in this invention. The equivalent resistance is 1/R eq =(1/R sh +1/(R s +R i )). For the First Photodiode used in the invention, R sh ≅10 MΩ, R s ≅800Ω and R i ≅0.72 yields an equivalent resistance R eq ≅800Ω corresponding to a time constant of R eq  C eq ≅16×10 −8  s (160 ns) for the First Photodiode at 25° C. Due to the fact that any additional reversed bias voltage is not applied to the First Photodiode, the photocurrent I ph (t) doesn&#39;t contain dark current and it contains the photocurrent induced by the average power of Pulsed Type Laser Source which has Poisson type noise distribution and Boltzmann Noise current. Even if not applying any reversed bias to the First Photodiode in the invention reduces the higher frequency limit, the noise limit of the First Photodiode of FCIS become better and this approach enables FCIS reaching a threshold level of 1 nA in non-cooling mode, corresponding to 16.5 pJ at 1550 nm level for a Duty Cycle of 0.17 at 1 MHz, −3 dB frequency range, in practice. 
         [0032]    In this section the pulse and the modulation frequency responses of FCIS based-LEMCS invented: Modulation frequency response of FCIS caused by the RC low pass filter type equivalent circuit consisting from the resistance and capacitance values of the First Photodiode, other effect restricting the pulse and the modulation frequency responses of FCIS is the time constant (τ) of FCIS, based on the diameter of the integrating sphere, coating average reflectance of the inner coating, and light velocity. The time constant (τ) of FCIS is an effective component on determination of average power P av  and resultantly averaged pulse energy by FCIS through the First Photodiode. 
         [0033]    By considering the below evaluations concerning with the modulation frequency response of FCIS through the First Photodiode against the rising, the falling edges of the optical light pulses together with pulse width PW, generated by Pulsed Type Laser Source, the pulse response of FCIS should be taken into account, because repetition rate of 1 MHz, corresponding to a period of 1 μs, should have the rise and the fall times relatively very lower than 1 μs. For these edges together with relatively short PW can be regarded as δ-delta impulse function for FCIS with an inner diameter of 15 cm which has the First Photodiode and the investigation is made according to the modulation frequency response pertaining to the repetition frequencies up to 1 MHz. As a result, it is obvious that increasing of the modulation frequency gives rise to shortening the rise and the fall time of the pulses as well as PW. In this case, the pulse energy term in Eq. (7) should contain the pulse response term. Therefore Eq. (7) can be rearranged and considered in two parts as in Eq. (9) and as in Eq. (10). First, the pulse response needing to be investigated for measuring P av  in the invention is that of the First Photodiode, behaving as a RC low pass filter against the optical pulses having increasing repetition rates. If the complete pulse response of a RC low pass filter circuit composed of the parallel combination of R eq  and C eq  is calculated, the rise time and the fall time along with PW at the output photocurrent I av  of the First Photodiode also exhibits exponential behavior. In this case, by assuming the laser pulse entering in FCIS, the peak power of P 0  can be written as Eq. (9) for single laser pulse, containing the pulse response of FCIS and the pulse response of the First Photodiode, and it should be noted that I ph0  should have a rectangular function form. 
         [0034]               (W) (9) 
         [0035]    Where is the pulse response of FCIS against the laser pulse and is the pulse response function of the First Photodiode of FCIS, respectively. A pulse can be divided into three parts. The first part is rising edge t r , the second part is pulse width PW, and the third part is falling edge, t f . However, in the characterization of the pulse response of the First Photodiode, to think an integrated and complete part of the response of the First Photodiode against the rising edge and the pulse width of the pulse is correct, because in these parts of time of the single pulse, the capacitors of the equivalent circuit are the state of charging and keeping stable. The third part of the single pulse directly corresponds to discharging the capacitors and so third part of the pulse should be represented by a different function. The pulse response function, which is composed of the summation the responses written for three pulse parts, directly relies on the time of charging of capacitors and discharging capacitors through relevant equivalent resistances. This analysis can easily be made by using a continuous convolution of the single pulse with the equivalent circuit of the First Photodiode. 
         [0036]               (10) 
         [0037]    Where is the multiplier for , which matches the initial voltage on C eq  just before the discharging of the equivalent capacitor C eq  was started for . The pulse energy of a single laser pulse including the pulse responses is, 
         [0038]               (W) (11) 
         [0039]    Where t r , and PW are the rise time, the fall time and the pulse width of the pulse of the laser pulse. For the single pulse &gt;&gt;160 ns, and t r &lt;&lt;PW for both pulse response functions;            
         [0000]    and =4.6(RC eq C eq )≅736 ns. The pulse width of 736 ns is sufficiently larger than 160 ns for this approximation, producing 0.99 I av . 
         [0040]    The parameter is the time constant of FCIS, ρ is the average reflectance of the inner coating of FCIS, D is diameter of FCIS, and c is the velocity of light in vacuum. The term corresponds to average number of reflections until a photon is to be absorbed [3 and 4]. It is possible to measure of FCIS by measuring the rise times of a very short pulse, which has a pulse width of a few ps, at the entrance port and at the detector port after first reflection. Regarding the time constant of FCIS, bearing in mind that quasi-exponential absorption behavior of the inner wall coating of FCIS having highly diffusive reflection is in accordance with the Beer Lambert Law for a photon flux emitted from Pulsed Type Laser Source and assuming that the inner coating of FCIS is nearly uniform and the inner volume of FCIS having a diameter of 15 cm is nearly isotropic, we can say that the pulse response of integrating sphere have an exponential behaviors for rise and fall times of the pulse of the Gaussian Laser Beam due to the time constant (τ) and the dissipation of diffusely reflected irradiance of a single light pulse on the entire inner surface of FCIS reaches to any point within an elapsed time Δt′ inside of FCIS [3 and 4]. According to the above assessments, if and for CW laser beam instead of pulse P av  goes to P 0 . If is smaller than, corresponding to ultra short pulse condition, there is no sufficient time for the uniform and diffuse reflection of a single pulse inside FCIS and P av  cannot be detected. One of the important points to determine the pulse and the modulation frequency response of the First Photodiode used in the application of measuring the average power of the Pulsed Type Laser Source in the invention is to characterize how many portion of Gaussian Laser Beam entering FCIS is diffusely reflected inside FCIS. For this characterization, the ratio between the diffuse power inside FCIS and the direct power entering in FCIS directly corresponds to =, which is the power efficiency between the diffuse power inside FCIS and the direct power entering in the FCIS, is the cutoff frequency of FCIS. The direct spectral responsivity calibration of FCIS based LEMS against Optical Power Transfer Standard, which will be described in the section “Determination of the spectral responsivity of FCIS based-LEMCS”, eliminates in Eq. (12) because (A/W) is obtained from the optical flux diffusely reflected inside FCIS and in is at the denominator in Eq. (12).The time constant of FCIS in the invention is ns, corresponding to for a wall coating having an average value of 0.90. In the pulse response function of FCIS based-LEMCS, the pulse response of FCIS based-LEMCS comprises two parts given in Eq. (12). The first part is related to the geometric characteristics of FCIS of FCIS based-LEMCS together with its inner coating property and the second part is related to the equivalent circuit of the First Photodiode. By comparing Eq. (10) and Eq. (11), Eq. (12) is written as a complete and final equation. 
         [0041]               (J) (12) 
         [0042]    In Eq. (12), it is seen that this type of pulse response function of the First Photodiode causes the distortion of the ideal pulse shape of photocurrent I ph0  generated by the single laser pulse, depending on time constant of the equivalent circuit  171  of the First Photodiode, R eq C eq . This shape distortion, is especially resulted from the relatively larger time constant of the First Photodiode R eq C eq =160 ns, rather than time constant of FCIS ns. The distortion occurs also in phase of the photocurrent pulse produced by the laser pulse with respect to the laser pulse. These distortions negatively affect to carry out the time/frequency related measurements by means of the First Photodiode. These distortions are characterized in  FIG. 2  as PW′ and DT′ for the photocurrent I ph (t) which is generated by the First Photodiode against Pulse Width and Dead Time of Pulsed/Chopped Gaussian laser beams of Pulsed Type Laser Source and Chopped Type Laser Source. To defeat the problematic condition resulted from the distortion based on unreliable time/frequency related measurements, a second photodiode having a relatively higher low cutoff frequency is placed and reserved in the invention, which is one of the new implementations presented in the invention. The averaged photocurrent measurements and time/frequency related measurements are carried out separately by different photodiodes, called the First Photodiode and called the second in the invention. 
         [0043]    The term of Eq. (12) for the single pulse &gt;&gt;160 ns, and PW&gt;&gt;t r , t f , which is the pulse response of the First Photodiode mounted to FCIS in Eq. (12), is an effective parameter for the relatively short pulse widths at the higher modulation frequencies, of which approaches 736 ns or shorter. A pulse width PW of 736 ns forms the upper time limit for the First Photodiode of FCIS in the invention together with sufficient and necessary Dead Time DT for heat dissipation, which is detailed in the section of “DESCRIPTION”. In case of using any other photodiode having R eq C eq  lower than 160 ns instead of the First Photodiode, to obtain a new PW narrower than 0.736 μs is obvious. At same time, this is also valid for the term of Eq. (12), which is the pulse response of FCIS of FCIS based-LEMCS in Eq. (12). The width of the laser pulses having wider than 4.6≅14 ns is sufficient to allow peak power P 0  of 0.99 to dissipate (spread) in the inner surface of FCIS. Due to the fact that both of the First Photodiode and the FCIS behave as a low pass filter, provided that the pulse width PW of Pulsed Type Laser Source is sufficiently wide, the peak pulse energy of the infinite laser pulse train is correctly measured. If the pulse width of Pulsed Type Laser Source is very short, relative to pulse response characteristics of FCIS and the First Photodiode, the rise and the fall times of infinite laser pulses of Pulsed Type Laser Source is retarded by low pass filter characteristics of the First Photodiode and the rise and fall times have slower slopes than original states. As a result this retarded rise and fall times causes to carry out measurement of averaged repetition period T av  (or averaged repetition frequency f av ) having low precision which corresponds to high measurement uncertainty in time/frequency related measurements by using the output photocurrent I ph (t) of the First Photodiode. And the pulse width PW and the dead time DT values of infinite laser pulse train of Pulsed Type Laser Source are sensed and converted as PW′ and DT′ as in  FIG. 3 . In order to defeat this problematic condition due to limited pulse response of the First Photodiode, in the invention, the time frequency related measurements are carried out by second photodiode. FCIS based-LEMCS is one embodiment and the variation in numerical values doesn&#39;t change the philosophy of the invention. 
         [0044]    The two of the most related international patents still in progress to the invention described herein are introduced at the following: 
         [0045]    The invention described in US2013250997 (A1) deals with the thermopile type laser energy conversion. The thermopile theory of detecting the laser pulse energy relies on the temperature drop between the hot and cold thermocouple junctions across which the heat, caused by laser energy, flows radially, and the temperature drop results in a voltage output proportional to laser energy applied. This voltage output proportional to laser energy is collected with an integrating circuit receiving the electrical output from the thermopile, such that the energy of at least one pulse of the beam can be determined by integrating over time the electrical output arising from the at least one pulse. The response time of such a thermopile sensor is typically no faster than 1 s for reaching 95% of the final reading and the maximum repetition period to be measured with this system was stated as 10 Hz. However, FCIS based-LEMCS doesn&#39;t contain any thermopile type temperature sensor. Instead of using a thermopile, FCIS based-LEMCS is mainly composed of newly configured integrating sphere assembled with the photovoltaic type photodiodes, called the First Photodiode and the Second Photodiode and the averaged pulse energy of the Pulsed Type Laser Source e is determine by measuring by the averaged photocurrent proportional to the peak power of the Pulsed Type Laser Source and by measuring time related measurements of the Pulsed Type Laser Source for a repetition frequency extending to 1 MHz, corresponding to a repetition period of 1 μs, which is relatively very higher response time with respect to the system described in 1J52013250997 (A1). FCIS based-LEMCS described herein is one embodiment, the upper cutoff frequencies of the First Photodiode and the Second Photodiode don&#39;t disturb the philosophy of the invention described herein and so the photodiodes, the cutoff frequencies of which are higher than 1 MHz and 6 GHz, really and undoubtedly get better. Additionally, both the First Photodiode and the Second Photodiode specified herein can be exchanged with different types of semiconductor detector depending on the spectral power distribution of the laser to be engaged in the application 
         [0046]    Another invention described in JPS63100335(A) deals with securely detecting the energy of a laser beam by providing a laser detector for detecting the energy of a laser beam which is reflected and uniformed by a laser beam scattering device, which is a motorized chopper, and an integrating sphere. The detector mounted to the integrating sphere in JPS63100335(A) senses the uniformly scattered and reflected laser beam portion and the invented systems acts as laser energy presence sensor. Any pulse energy measurement procedure of laser is not seen in JPS63100335 (A). However, beyond the detection of presence of laser energy, FCIS based-LEMCS described herein provides both the measurement capability of the averaged pulse energy of the Pulsed Type Laser Source and the calibration of Commercial Laser Energy Meter against FCIS based-LEMCS by using Chopped Type Laser Source, which is a part of FCIS based-LEMCS, and which is traceable to primary level standards. 
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       [0000]    
       
         [1] Oguz Celikel, Ozcan Bazkir, Mehmet Krucukaglu, and Ferhat Samedov, “Cryogenic radiometer based absolute spectral power responsivity calibration of integrating sphere radiometer to be used in power measurements at optical fiber communication wavelengths”,  Optical and Quantum Electronics.  37, 529-543, (2005). 
         [2] Ferhat Sametoglu “New traceability chains in the photometric and radiometric measurements at the National Metrology Institute of Turkey”.  Optics and Lasers in Engineering  45,36-42, (2007). 
         [3] Volker jungnickel, Volker Pohl, Stephan Nönnig, and Clemens von HeImolt “Physical Model of the Wireless Infrared Communication Channel”  IEEE Journal on Selected Areas in Communications , vol. 20, no. 3, 631-640, (April 2002). 
         [4] Labsphere Technical Guide: Integrating Sphere Photometry and Radiometry.
 
http://www.labsphere.com/uploadsitechnical-guidesia-guide-to-integrating-sphere-radiometry-and-photometry.pdf
 
         [5] Oguz Celikel “Mode Field Diameter and cut-off wavelength measurements of single mode optical fiber standards used in OTDR calibrations”  Optical and Quantum Electronics.  37, 587 (2005). 
       
     
         [0052]    [6] David Bergstrom “The Absorption of Laser Light by Rough Metal Surfaces”, Doctoral Thesis, Department of Engineering. Physics and Mathematics Mid Sweden University 
         [0000]    Östersund, Sweden, February 2008. 
       SUMMARY 
       [0053]    After the completion of the investigation about the pulse responses of FCIS of FCIS based-LEMCS and the First Photodiode mounted to FCIS for a single pulse application in this invention, this section mainly deals with describing the averaged pulse energy including the modulation frequency response function of integrating sphere part of FCIS together with that of the First Photodiode mounted to FCIS so as to reach the exact averaged pulse energy values of Pulsed Type Laser Source and Chopped Type Laser Source, which produces the reference and averaged pulse energy to be used for calibrating Commercial Laser Energy Meter because the invented FCIS based-LEMCS is subjected to infinite laser pulse train, which is composed of an infinite series of single laser pulse in time domain. 
         [0054]    In the invention, 
         [0055]    a-) As a new configuration, FCIS based-LEMCS to be engaged for measuring the averaged pulse energy PE av  of a Pulsed Type Laser Source having Pulsed Gaussian Laser Beams as infinite pulse train in time domain is described. 
         [0056]    b-) A new apparatus, called FCIS based-LEMCS and the calibration method belonging to the new apparatus along with a newly configured FCIS based-LEMCS equipped with a series of choppers, which is one embodiment, which contains a Chopped Type Laser Source obtained from CW Laser Sources, and which enable us adjusting the Duty Cycles changing from 0.17 to 0.84 at the repetition frequencies varying from 5 Hz to 2 KHz, is described to make the traceable calibrations of Commercial Laser Energy Meters, which operates on the spectral range of 900 nm-1650 nm over the averaged pulse energy range of 16.5 pJ to 100 mJ, to primary level standards. With the choice to use an electronic amplitude modulator instead of a group of choppers in the invention, constructed as one embodiment, upper frequency level of 2 kHz, which is available by means of DC motor having a rare earth doped magnet can be expandable to 1 MHz region, which is the cutoff frequency of the First Photodiode. 
         [0057]    In FCIS of FCIS based-LEMCS, two photodiodes are used, labeled as the First Photodiode and the Second Photodiode. The former is engaged in the measurement of average photocurrent I av , resulted from the average power of the Pulsed Type Laser Source and the latter is used in repetition period T (and/or f av ) measurements of the Pulsed Type Laser Source. For FCIS based-LEMCS, it is seen and proved that the repetition frequency range for an electronic type modulator instead of DC motor driven choppers, which is to be used to construct Chopped Type Laser Source in the traceable calibration of Commercial Laser Energy Meters in the invention, can be extend up to 1 MHz, which is the cutoff frequency limit of the First Photodiode. For the frequencies beyond 1 MHz, the pulse response and modulation response functions mentioned in the section of “BACKGROUND” should be taken into account. 
         [0058]    As seen in the time constants of FCIS and the First Photodiode mounted to FCIS, the modulation frequency range of integrating sphere of FCIS is wider than that of the First Photodiode and so bearing in mind that for the Pulsed Type Laser Source, T av (=1/f) is equal to the averaged values of (PW+DT+t r +t f ), it is enough to write the average photocurrent L as a function of the modulation frequency of the Pulsed Type Laser Source so as to define the modulation frequency dependency of the resultant averaged pulse energy value PE av  in unit of J, caused by the dependency of the First Photodiode only. The cutoff frequency of FCIS is 53 MHz. In this case, the modulation frequency response function of FCIS is assumed as 1 for the frequency band of 0-1 MHz in which the First Photodiode operates. By considering the Fourier Series expansion of an infinite and periodic pulse train, the averaged repetition frequency of which is f av =1 MHz, the highest amplitude of the first odd frequency component of Fourier series expansion belonging to the infinite and periodic pulse train is at f=1 MHz. The following frequencies together with a DC component are 2 MHz, 3 MHz, . . . ,n f, with the decreasing amplitude. In this case, the other following frequency contents higher than 1 MHz constituting the infinite and periodic pulse train are attenuated with a relatively higher slope (20 dB/decade) by the First Photodiode behaving as a RC low pass filter. The cutoff frequency of which is ˜1 MHz (=1/(2πR eq C eq )=995222 Hz). With this brief evaluation, instead of summing all of the frequency responses of the First Photodiode against the infinite and periodic pulse train, the first Fourier term, which has sinusoidal behavior, is considered and the modulation frequency response function of the First Photodiode is calculated according to sinus function, the linear frequency of which corresponds to the averaged repetition frequency f av  (Hz), the first odd frequency component of Fourier series expansion of infinite and periodic pulse train. This approach gives very good explanation for the modulation frequency dependence of FCIS. As a result, the final form of PE av  in Eq. (13) is calculated by multiplying I ph (t) in Eq. (12) with the modulation frequency transfer function of the equivalent circuit of the First Photodiode, behaving as a RC low pass filter in  FIG. 3 , for the sufficiently wide pulse widths. For the infinite laser pulse train generated by Pulsed Type Laser Source, the averaged pulse energy is given in Eq. (13); 
         [0059]               (J) (13) 
         [0060]    Eq. (14) characterizes Eq. (13) as a function of the repetition frequency f av  (Hz), corresponding to the modulation frequency response functions of FCIS based-LEMCS and the First Photodiode, instead of the pulse response functions terms in Eq. (9) and Eq. (10). 
         [0061]               (14) 
         [0062]    Where the phase terms of Eq. (15), based on frequency terms, is discarded. The term , caused by time constant of FCIS τ (s) in Eq. (10), can be neglected and dropped for the repetition frequencies up to the upper frequency limit of 1 MHz of the First Photodiode valid in this invention, is the high frequency cutoff limit of the First Photodiode, behaving as a RC low pass filter in  FIG. 3 , which can be calculated from (R eq ,C eq ) as ˜1 MHz (1/(2πR eq C eq )=995222 Hz) theoretically. 
         [0063]    The frequency range from 0 Hz up to 1 MHz, which is also obtained by the theoretical calculations, is verified by the measurements carried out by FCIS assembled with the electrometer. The role of the modulation response function of the First Photodiode is presented in Eq. (14). The resultant averaged peak pulse energy PE, of a Pulsed Type Laser Source as a function of the averaged repetition frequency (f av =1/T av ) is given in Eq. (16), by considering the first odd term of Fourier Expansion series of the pulse train having a varying PW. Eq. (16) is a well suited model function for FCIS of FCIS based-LEMCS in the invention, characterizing both of the modulation frequency response and the pulse response of the FCIS system. Considering the, the modulation frequency response function of the whole of FCIS composed of an integrating sphere and the First Photodiode consists of only for the repetition frequency range extending from 0 to 1 MHz, by multiplying with. However, the robustness of the method presented in the invention give us an advantage to eliminate. Averaged pulse energy of the Pulsed Type Laser Source is as follows by considering the modulation frequency response function of FCIS based-LEMCS, which is final equation by which the averaged pulse energy is calculated in the invention. 
         [0064]               (J) (16) 
         [0065]    Where due to that fact that is very high relative to the operation frequency range of FCIS based-LEMCS which is up to 1 MHz in measuring the averaged pulse energy of Pulsed Type Laser Source and is 2 kHz in calibration of Commercial Laser Energy Meter against FCIS based-LEMCS invented, the term is not included in Eq. (16). This is also valid for the range of the repetition frequency of 1 MHz., which is determined from the calibration of FCIS against Optical Power Transfer Standard. The direct spectral responsivity calibration of FCIS based LEMS against Optical Power Transfer Standard, which will be described in the section “Determination of the spectral responsivity of FCIS based-LEMCS” eliminates in Eq. (16) because (A/W) is obtained from the optical flux diffusely reflected inside FCIS and in is at the denominator in Eq. (16). 
         [0066]    If the background current I bc , which fluctuates around zero line, takes place in the First Photodiode, this background current I bc  is subtracted from I av  to obtain correct averaged photocurrent caused by Gaussian laser pulses produced by Pulsed Type Laser Source. Duty Cycle=f av ·PW av =(N·PW av )/T av  N is 1 for infinite pulse train generated by Pulsed Type Laser Source in this invention. Due to the fact that and the averaged repetition period T av  (s) are measured within a time interval determined by the average times of Electrometer and Time Interval Counter adjusted by operator during the pulse energy measurements, these are directly averaged values. 
         [0067]    NOTE: The time/frequency related parameters, which are f (Hz), T (s), PW (s) DT (s) and stated in the text are not time averaged values. However; f av (Hz), T av (s), PW av , (s), and DT av  (s) parameters are the time averaged values obtained from the measurements of the time/frequency related parameters, which are f (Hz), T(s), PW (s), DT (s), by means of Time interval Counter of FCIS based-LEMCS within a time interval adjusted by operator. 
         [0068]    Time/frequency related measurements (T av  and f av ) in Eq. (16), which are traceable to  133 Cs (or  87 Rb) frequency standard through a commercial Time Interval Counter, are directly performed by fully eliminating the effect of relatively lower cutoff frequency of the First Photodiode and the effects of the time constant of FCIS on dissipation rate of the irradiation of P(t) diffusely reflected after collision of a Pulsed Gaussian Laser Beams of Pulsed Type Laser Source on the diffusive inner surface of FCIS with a novel placement of a fast response photodiode in the conventional integrating sphere, called as the Second Photodiode. This elimination is achieved with help of an internal steel hemisphere placed inside FCIS assembled with the first MM optical fiber patch cord having a Zr ferrule, the core diameter of which is 62.5 μm, and this is applicable for the integrating spheres to be used for higher peak laser energy the inner diameter of which is larger than 15 cm. The entrance port of FCIS and the center position of internal steel hemisphere are coincided on the same optical axis and the optical pulses strike on Zr ferrule settled on the center of the internal steel hemisphere first. The time/frequency related measurements are directly carried out for the pulse strikes of Pulsed Type Laser Source and the pulse strikes of Chopped Type Laser Sources by the combination of the Second Photodiode, Fast Current to Voltage Converter, and Time Interval Counter. With this configuration, all of the time measurements are performed as free of the time constant (τ=3 ns) of integrating sphere of FCIS and free of time constant of R eq C eq ≅16×10 −8  s (160 us) of the First Photodiode used to measure average power I av . The measurements of in Eq. (16) are carried out by an electrometer, the traceability of which comes from primary resistance standard, Quantum Hall System, and comes from primary direct voltage standard, DC Josephson System. The traceability of optical power scale of FCIS, which corresponds to the spectral responsivity of FCIS, in Eq. (16) through the First Photodiode is provided by an 
         [0069]    Optical Power Transfer Standard, InGaAs based spectralon sphere radiometer, as one embodiment in the invention. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0070]      FIG. 1 . The invented Fiber Coupled Integrating Sphere Based-Laser Energy Meter and Calibration System (FCIS based-LEMCS) without Chopped Type Laser Source in the measurement of the averaged peak pulse energy of a Pulsed Type Laser Source. 
           [0071]      FIG. 2 . The setup for calibration of Commercial Laser Energy Meter against FCIS of FCIS based-LEMCS by FCIS based-LEMCS. This drawing shows the whole of FCIS based-LEMCS with the dashed lines. 
           [0072]      FIG. 3 . Pulse characteristics of Pulsed Type Laser Source Chopped Type Laser Source the average pulse energy of which is to be measured by FCIS based-LEMCS in the invention and the photocurrent proportional to the average optical power P av  generated by the First Photodiode. 
           [0073]      FIG. 4 . The details and the components of FCIS of FCIS based-LEMCS and reflection properties together with the placements of Pulsed Type Laser Source and Chopped Type Laser Source. 
           [0074]      FIG. 5 . Details of stainless steel body of internal steel hemisphere for the energy transfer and laser pulse parameter calculations in the determination of the pulse energy damage limit. 
           [0075]      FIG. 6 a   . Choppers mounted on the DC motor, which has a rare earth doped magnet, 0.83, 0.75, 0.67, and 0.58 at constant repetition frequency of          . These choppers in the invention are used to construct Chopped Type Laser Source from CW Laser Source(s), which is to be engaged as a reference and averaged pulse energy in traceable calibration of Commercial Laser Energy Meter. 
           [0076]      FIG. 6 b   . Choppers mounted on the DC Motor, which has a rare earth doped magnet, to generate Duty Cycles of 0.50, 0.42, 0.33, 0.25 and 0.17 at constant repetition frequency of          . These choppers in the invention are used to construct Chopped Type Laser Source from CW Laser Source(s), which is to be engaged as a reference and averaged pulse energy in traceable calibration of Commercial Laser Energy Meter. 
           [0077]      FIG. 7 . Traceability chain of FCIS based-LEMCS, which is to be used in both measuring the averaged pulse energy PE av  of Pulsed Type Laser Source and calibrating Commercial Laser Energy Meters by using the reference and averaged pulse energy of Chopped Type Laser Source of FCIS based-LEMCS. 
           [0078]      FIG. 8 . The setup for the determination of spectral responsivity (A/W) of FCIS of FCIS based-LEMCS traceable to Cryogenic Radiometer, primary level optical power standard (W). 
           [0079]      FIG. 9 a   . The uncertainty budget belonging to FCIS based-LEMCS for an averaged pulse energy PE av  of 40 μJ as a rated value. 
           [0080]      FIG. 9 b   . The uncertainty budget belonging to FCIS based-LEMCS for an averaged pulse energy PE av  of 100 mJ as a rated value. 
       
    
    
     DESCRIPTION 
       [0081]    The details of FCIS based-LEMCS  111 , which is constructed as one embodiment, which is used to measure the averaged pulse energy of a Pulsed Type Laser Source  500  and to calibrate a Commercial Laser Energy Meter  999  with the reference and averaged pulse energy generated by Chopped Type Laser Source  600  in the structure of FCIS based-LEMCS  111 , which is traceable to primary level standards, are presented herein. 
         [0082]    FCIS based-LEMCS  111  which is the subject of the invention is completely shown in  FIG. 2 . The structural body of FCIS based-LEMCS  111  consists of the configuration of FCIS  100  detailed in  FIG. 4 , internal steel hemisphere assembled with Zr ferrule  140  of HMS connector  132  of a First MM Optical Fiber Patch Cord  150  detailed in  FIG. 5 , nine separate choppers  901 - 909  detailed in  FIG. 6 a    and  FIG. 6 b   , which are mountable to DC Motor  599 , an Electrometer  119 , a Time Interval Counter  135 , an Oscilloscope  130 , a Mechanical Attenuator  170 , an Alignment Combination  162  and a second MM optical fiber path cord  160  shown in  FIG. 1  and  FIG. 2 . Even though the Electrometer  119 , the Time Interval Counter  135 , the Oscilloscope  130 , the Mechanical Attenuator  170 , the Alignment Combination  162 , the first MM optical fiber path cord  150  and the second MM optical fiber path card  160 , which are general purpose measurement instruments and apparatus, are excluded from the invention individually, they are included in the invention for both the measurement procedure of the averaged pulse energies  840  of Pulsed Type Laser Source  500 , and the calibration of Commercial Laser Energy Meters  999  to be performed by using the reference and averaged pulse energies  845  of Chopped Type Laser Source  600  of FCIS based-LEMCS  111 , all of which are traceable to primary level standards demonstrated in  FIG. 7 . 
         [0083]    In addition to traceable measurements of the averaged pulse energy  840  of Pulsed Type Laser Source  500  by FCIS based-LEMCS  111 , the traceable calibration of Commercial Laser Energy Meters  999 , which measure the averaged pulse energy, are carried out by the reference and averaged pulse energies  845  generated by means of Chopped Type Laser Source  600 , which is a part of FCIS based-LEMCS  111 . The method of traceable calibration of Commercial Laser Energy Meters  999  via FCIS based-LEMCS  111  is included in the invention. The invention is summarized at the following three items; 
         [0084]    1-) The averaged pulse energy measurement section of FCIS based-LEMCS  111  designed for measuring the averaged pulse energy PE av    840  of Pulsed Type Laser Source  500  shown in  FIG. 1 , consists of an Al-integrating sphere having a diameter of 150 mm, called as FCIS  100  in the invention, an internal steel hemisphere  110  assembled with Zr ferrule  140  of HMS connector  132  of a First MM Optical Fiber Patch Cord  150 , which is mounted inside FCIS  100 , the details of which are given in  FIG. 4 , the Electrometer  119  able to measure the photocurrent I av    300  generated by the First Photodiode  120  mounted on Port_ 2   102  of FCIS  100  of FCIS based-LEMCS  111 , the Second Photodiode  129  mounted on Port_ 3   103  of FCIS  100  of FCIS based-LEMCS  111  through the First MM Optical Fiber Patch Cord  150  having Zr ferrule  140 , which is to be used in time and frequency measurements together with Time Interval Counter  135  and the Oscilloscope  130  in  FIG. 1 . 
         [0085]    2-) The composition of FCIS based-LEMCS  111 , which is a series of separate choppers  901 - 909  to construct a Chopped Type Laser Source  600  generating the reference and averaged pulse energy  845  for the calibration of Commercial Laser Energy Meter  999  together with all of the equipments, all of the parts, all of the configurations stated in item “1-)” just above. The whole of FCIS based-LEMCS is shown in  FIG. 2 . The combination of a DC motor  599  with a series of separate choppers of FCIS based-LEMCS  111 , each of which has individual Duty Cycle shown in  FIG. 6 a    and  FIG. 6 b   , is used in establish Chopped Type Laser Source  600  generating an infinite pulse train from CW Laser Sources  800  in  FIG. 2  and  FIG. 3  in order to calibrate Commercial Laser Energy Meters against FCIS based-LEMCS  111 , traceable to primary level standards. In brief, Chopped Type Laser Source  600  of FCIS based-LEMCS  111  generates the reference and averaged pulse energy  845  to calibrate Commercial Laser Energy Meters  999 . 
         [0086]    3-)The measurement method of the averaged pulse energy PE av    840  of the Pulsed Type Laser Source  500  with FCIS based-LEMCS  111 , and the calibration method of a Commercial Laser Energy Meter  999  against Chopped Type Laser Source  600  of FCIS based-LEMCS  111 , both of which are traceable to primary level standards. 
         [0087]    Due to the fact that the FCIS based-LEMCS  111  is one embodiment the variation in the properties and the number of the choppers generating different Duty Cycles doesn&#39;t disturb the philosophy of the invention. Additionally, FCIS based-LEMCS  111  described herein is one embodiment, the upper cutoff frequencies of the First Photodiode  120  and the Second Photodiode  129  don&#39;t disturb the philosophy of the invention described herein and so the photodiodes, the cutoff frequencies of which are higher than 1 MHz and 6 GHz, really and undoubtedly get better. Additionally, both the First Photodiode and the Second Photodiode specified herein can be exchanged with different types of semiconductor detector depending on the spectral power distribution of the laser to be engaged in the application. 
         [0088]    1. Details of FCIS 
         [0089]    The FCIS  100  of FCIS based-LEMCS  111  has three ports: These are Laser Entrance Port  101  (Port_ 1 ), Average Optical Power Measurement Port  102  (Port_ 2 ), and Time/Frequency Related Measurement Port  103  (Port_ 3 ). These ports dwell on the same equator line of the FCIS shown as in  FIG. 4 . 
         [0090]    Port_ 1 ; 
         [0091]    The diameter of Port_ 1   101  is 8 mm. The diameter of 8 mm of Port_ 1  enables Pulsed Gaussian Laser Beam  501  of Pulsed Type Laser Source  500 , Chopped Gaussian Laser Beam  601  of Chopped Type Laser Source  600 , and CW Laser Source  800 , sequentially shown in  FIG. 1 ,  FIG. 2 , and  FIG. 8 , to enter in FCIS  100  of FCIS based-LEMCS  111  without any contact by considering the beam waits and total beam diameters in the measurement of the averaged pulse energy PE av    840  of Pulsed Type Laser Source  500  of  FIG. 1 , in the measurement of the reference and averaged pulse energy  845  of Chopped Type Laser Source  600  of  FIG. 2  and in the determination of spectral responsivity  320  of FCIS  100  of FCIS based-LEMCS  111  with the CW Gaussian Laser Beam  799  of CW Laser Source  800  of  FIG. 8 . The distance and beam divergence correlations among the point z=0 and Port_ 1   101  and the center of the internal steel hemisphere  110  in  FIG. 1 ,  FIG. 2 , and  FIG. 8  should provide the contactless passing of the Pulsed Gaussian Laser Beam  501 , Chopped Gaussian Laser Beam  601 , and CW Gaussian Laser Beam  799 . 
         [0092]    The following calculations related to beam waist and beam divergences to be carried out for CW Gaussian Laser Beam  799  of CW Laser Source  800 , which are used to construct Chopped Type Laser Source  600  of FCIS based-LEMCS  111  in  FIG. 2  by means of a series of choppers  901 - 909  shown in  FIG. 6 a   , and  FIG. 6 b   , which generates the reference and averaged pulse energy  845  to be used in the calibration of Commercial Laser Energy Meter  999  against FCIS based-LEMCS  111  are also taken into account for the measurement of the averaged pulse energy PE av    840  of Pulsed Type Laser Source  500 . 
         [0093]    The four distributed feedback (DFB) laser diodes, each of which is called as CW Laser Source  800  in FCIS based-LEMCS  111  constructed as one embodiment in the invention, each of which individually radiates at 980.0 nm, 1064.0 nm, 1309.0 nm, and 1549.0 nm, and all the four of which have individual Single Mode (SM) Optical Fiber Patch Cards  876  assembled with the individual collimators, are used in the determination the spectral responsivity of FCIS  100  of FCIS based-LEMCS  111  in  FIG. 8  and in the traceable calibration of Commercial Laser Energy Meters  999  in  FIG. 2  obtained by means of the nine different choppers  901 - 909  shown in  FIG. 6 a    and  FIG. 6   b.    
         [0094]    Single mode propagation inside the optical fiber patch cords of the four laser diodes means the field distribution of quasi transverse electric mode (LP 01 ) HE 11 , no higher order modes. The width (beam waist w(z), 1/e 2  (13.53%) points of the irradiance level) change of the irradiance distribution at the output of the single mode optical fiber, corresponding to Gaussian beam profile, is the function of the numerical aperture of the relevant single mode optical fiber of the patch cord [5] and these beam waists of the irradiance distributions diverge, depending on the distance z from the end of fiber, the wavelength and the spectral band width which is relatively narrow for DFB lasers. Beam divergence of a Gaussian beam is described as θ=Arctan (w(z)/z) in (rad) or (deg), where w(z) is the beam waist at any distance z (mm) on the propagation way of the laser beam emerging from the output of the Single Mode (SM) Optical Fiber Patch Cord with Collimator  876  of each CW Laser Sources  800 . The total beam divergence is equal to 2θ. 
         [0095]    w(z=0)=2.0 mm, beam divergence 1.20 mrad at 980.0 nm, 
         [0096]    w(z=0)=2.4 min, beam divergence 1.50 mrad at 1064.0 nm, 
         [0097]    w(z=0)=2.7 mm, beam divergence 1.50 mrad at 1309.0 nm, 
         [0098]    w(z=0)=2.8 min, beam divergence 1.52 mrad at 1549.0 nm. 
         [0099]    For a distance of 300 mm between the output of the Single Mode (SM) Optical Fiber Patch Cord with Collimator  876  and the center of the internal steel hemisphere  110 , the beam divergence calculations are performed. The distance of 300 mm means a distance extending from z=0 to the center of internal steel hemisphere  110  where a Pin Hole  109  with a diameter of 0.1 mm is drilled and Zr ferrule  140  of HMS Connector  132  of the First MM Optical Fiber Patch Card  150  is located in the center position of the internal steel hemisphere  110  and 0.2 mm back from the center surface of internal steel hemisphere  110  at rest position shown in  FIG. 4  and  FIG. 5 . In this case the total beam waists with the relevant divergences for the distance of 300 mm at the center of internal steel hemisphere  110  are calculated as follows: 
         [0100]    The total beam divergence 2θ=0.72 mm and the total beam waist is 2.72 mm for 980.0 nm CW Laser Source  800 , 
         [0101]    The total beam divergence 2θ=0.90 mm and the total beam waist is 3.30 mm for 1064.0 nm CW Laser Source  800 , 
         [0102]    The total beam divergence 2θ=0.90 mm and the total beam waist is 3.60 mm for 1309.0 nm CW Laser Source  800 , 
         [0103]    The total beam divergence 2θ=0.92 mm and the total beam waist is 3.72 mm for 1549.0 nm CW Laser Source  800 . 
         [0104]    Port_ 2 ; 
         [0105]    Port_ 2   102  is an aperture, the diameter of which is 2 mm, as shown in  FIG. 4 . The First Photodiode  120  is located in Port_ 2   102 . The average photocurrent measurements  300 , and  842 , which are related to the average optical power P av    301  of either Pulse Type Laser Source  500  or Chopped Type Laser Source  600  as in  FIG. 3  respectively, are carried out by means of the First Photodiode  120  connected to the Electrometer  119  able to measure the levels of sub-femto amperes in high accuracy mode. In addition to the averaged photocurrents labeled as  300 , and  842 , the First Photodiode  120  of FCIS  100  of FCIS based-LEMCS  111  generates the photocurrent I resp    200  during the traceable spectral responsivity calibration of FCIS  100  of FCIS based-LEMCS  111 , shown in  FIG. 8 . 
         [0106]    This photocurrent I resp    200  of the First Photodiode is used for deriving the spectral responsivity of FCIS  100  by dividing I resp    200  with P cw   _   resp  (λ)  201 , which is obtained from Optical Power Transfer Standard  809  directly. 
         [0107]    The First Photodiode  120  mounted to Port_ 2   102  generates the photocurrents proportional to the irradiance levels of Pulsed Gaussian Laser Beams, Chopped Gaussian Laser Beams, and CW Gaussian Laser Beams entering from Port_ 1  without saturation up to an average optical power of ˜158 W by considering its saturation level of 7 mW. The photocurrent produced by the First Photodiode  120  is converted into voltage and averaged by the Electrometer  119 . The First Photodiode  120  at Port_ 2   102  can operate up to a repetition rate of 1 MHz, which is the cutoff limit of the First Photodiode  120 . The details about the pulse and the modulation frequency response characteristics of the First Photodiode  120  are introduced in the Sections “Background” and “Summary”. In the invented FCIS based-LEMCS, the First Photodiode  120  located in Port_ 2   102  is used for only measuring the average photocurrent  300 , and  842  resulted from the average optical powers P av    301  of Pulsed Type Laser Source  500 /Chopped Type Laser Source  600  in Eq. (16) only. In measuring the time/frequency related parameters of Pulsed Type Laser Source  500  and Chopped Laser Source  600 , the First Photodiode  120  at Port_ 2   102  has not any responsibility, the main and the single mission of the First Photodiode  120  of FCIS  100  of FCIS based-LEMCS  111  is only to measure the average photocurrents proportional to the averaged optical power levels P av    301  of Pulsed Type Laser Source/Chopped Type Laser Source as shown in  FIG. 3 . Furthermore, according to Eq. (16), the spectral responsivity  320  of FCIS of FCIS based-LEMCS needed to calculate the averaged pulse energy  840  of Pulsed Type Laser Source  500  and the reference and averaged pulse energy  845  of Chopped Type Laser Source  600 , corresponding to spectral responsivity of the First Photodiode  120  mounted to Port_ 2   102 , is performed by its direct comparison to Optical Power Transfer Standard, calibrated against CR  803  [1] and, the First Photodiode  120  produces an averaged photocurrent I resp    200  in the determination process of the spectral responsivity  320 . 
         [0108]    All the average photocurrents and I resp    200  generated produced by the First Photodiode  120  mounted to Port_ 2   102  are collected and averaged by the Electrometer  119 , which is traceable to Quantum Flail Resistance Standard and DC Josephson Voltage Standard through Reference Resistance Bridge as shown in  FIG. 7 . The traceability chain for and (A/W  320  is also demonstrated in  FIG. 7 . 
         [0109]    Port_ 3 ; 
         [0110]    The aims of the use of the Second Photodiode  129  linked to Port_ 3   103  of FCIS  100  of FCIS based-LEMCS  111  through Mechanical Attenuator and the first MM optical fiber patch cord as in  FIG. 1  and  FIG. 2  and are i-) to perform the time/frequency related measurements of Pulsed Type Laser Source  500  Chopped Type Laser Source  600  without the effect of time constant of FCIS  100  and without the effect of the relatively lower cutoff frequency of the First Photodiode  120  and ii-) to coincide the Optical Axis  398  of FCIS based-LEMCS  111  with the those of the Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800  highly repetitively so as to obtain high measurement reproducibility. In addition to time/frequency related measurements of Pulsed Type Laser Source  500 , Chopped Type Laser Source  600  during PE av    840  and  845  measurements, the Second Photodiode  129  is also used for highly repetitively coinciding the Optical Axis  398  of FCIS based-LEMCS  111  with the Optical Axes  398  of the Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800  entering from Port_ 1  inside FCIS in  FIG. 1 ,  FIG. 2 , and  FIG. 8  during the measurements of the averaged pulse energy PE av    840  of Pulsed Type Laser Source  500 , the determination of the averaged and reference pulse energy  845  of Chopped Type Laser Source for the calibration of Commercial Laser Energy Meters  999 , and the determination of (A/W)  320  of FCIS  100  of FCIS based-LEMCS  111  against Optical Power Transfer Standard  809 . Thanks to coinciding the Optical Axis  398  of FCIS  100  with those of the Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800  entering from Port_ 1  inside FCIS  100  by means of the inclination of 25° of Internal Steel Hemisphere  110  settled inside FCIS  100  in the invention, extraordinary reproducibility and repeatability in the determination of , and the measurements of PE av    840  and  845  are observed. 
         [0111]    The FC/PC connector side of the First MM Optical Fiber Patch Cord  150  is joined to input of Mechanical Attenuator  180  and then the output of Mechanical Attenuator  180  is combined to the Second Photodiode  129  through the First MM Optical Fiber Patch Cord  160 . The photocurrent generated by the Second Photodiode  129  is transformed into voltage by a Current to Voltage Converter  127  Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  is mounted inner center surface of internal steel hemisphere  110 , which directly sees Port_ 1101 , and which is settled on the equator line inside FCIS  100  of FCIS based-LEMCS  111  with an angle, i.e. 25° in the invention, which is shown in  FIG. 4 . With this inclination of internal steel hemisphere  110  inside FCIS  100 , the First Photodiode  120  used in measuring I av    840 ,  845 , and I resp    200  is protected from first reflections of Pulsed Gaussian Laser Beam  501  of Pulsed Type Laser Source  500 , and Chopped Gaussian Laser Beam  601  of Chopped Type Laser Source  600  entering in Port_ 1   101 . The same approach is also valid for CW Gaussian Laser Beam of CW Laser Sources used in the determination of spectral responsivity  320  of FCIS  100  of FCIS based-LEMCS  111  against Optical Power Transfer Standard  809 , and the sufficiently diffusely reflected beams  148  depicted as in  FIG. 4  fall on the active area of the First Photodiode  120  mounted to the Port_ 2   102  having a diameter of 2 mm. The first reflection  149  takes place towards the wall opposite the First Photodiode  120  and onto the same section of the inner surface wall of FCIS  100  of FCIS based-LEMCS  111  with the inclination of 25° of Internal Steel Hemisphere  110  settled inside FCIS  100 , coated with BaSO 4    105 , reflects the beam, which is reflected first from the center of the polished/mirrored inner surface of internal steel hemisphere  110 , interior surface of FCIS  100  of FCIS based-LEMCS  111  diffusely. The orientation of the First Reflection  149  with the special inclination of 25° of Internal Steel Hemisphere  110  onto the same inner surface wall of FCIS  100  provides highly reproducible measurements. This placement and the inclination of Internal Steel Hemisphere  110  on Port  3   103  of FCIS  100  is one of the most important properties of the invention. Additionally, whenever Pulsed Gaussian Laser Beams  501  of Pulsed Type laser Source  500  or Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600  or CW Gaussian Laser Beam  799  of CW Laser Source  800  entering in FCIS  100  through Port_ 1   101  collides on the center of internal steel hemisphere  110  inclined, i.e. 25° in the invention, it is specularly reflected, called as a first reflection  149  in  FIG. 4 , to the wall opposite the First Photodiode  120  settling on the same equatorial line. The Pulsed Gaussian Laser Beams  501  or Chopped Gaussian Laser Beams  601  or CW Gaussian Laser Beam  799  colliding on the center of internal steel hemisphere  110  begins to distort and their beam waists start to expand after colliding the center of internal steel hemisphere  110  due to the inner curvature of internal steel hemisphere  110  and the presence of Pin Hole  109  at the center of internal steel hemisphere  110 . The distortion and the expansion of the first reflection beam  149  forms relatively very larger area on the wall coated with BaSO 4    105 . This type positioning and use of internal steel hemisphere  110  inside FCIS  100  is very practical for not damaging BaSO 4  coated wall  105  of FCIS  100  and moreover, a sufficient diffuse reflection interior FCIS  100  in the invention occurs, increasing the measurement reproducibility in the invention. 
         [0112]    Port_ 3   103  is so drilled with an angle that Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150 , the length of which is 10 mm, and the outer diameter of which is 2.5 mm, extends to the position 0.2 mm back from the inner surface of internal steel hemisphere  110  as in  FIG. 4  in detail. The First MM Optical Fiber Patch Cord  150  has a SiO 2  core, the diameter of which is 62.5 μm. The crest of Pulsed Gaussian Laser Beams  501  of Pulsed Type laser Source  500  or the crest of Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600  or the crest of CW Gaussian Laser Beam  799  of CW Laser Source  800  entering in FCIS  100  through Port _ 1   101  is continuously fallen onto the tip of Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  shown as in  FIG. 1 ,  FIG. 2 , and  FIG. 8  by means of Alignment Combination  162 . Then the Optical Axis  398  of FCIS  100  and the optical axes of Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800  shown in  FIG. 1 ,  FIG. 2 , and  FIG. 8  are coincided by means of Alignment Combination  162  by on line tracking and maximizing the voltage amplitude at the output of a Current to Voltage Converter  127  joined to the Second Photodiode  129  on the screen of the Oscilloscope  130 . The relative maximum signal amplitude means that the crest of Pulsed Gaussian Laser Beams  501  of Pulsed Type laser Source  500  or the crest of Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600  or the crest of CW Gaussian Laser Beam  799  of CW Laser Source  800  directly collides/falls on Zr ferrule  140  placed on the center of internal steel hemisphere  110 . This process and the configurations in the invention considerably increase the measurement reproducibility and repeatability. In order to coincide the optical axes of Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800  entering from Port_ 1   101  with the Optical Axis  398  settling on the core of Zr ferrule  140  of the First MM Optical Fiber Patch Cord  150  on Port_ 3   103  during the measurements of I av    300 ,  842 , and I resp    200  is difficult. In order to overcome the difficulty, in the invention, an internal steel hemisphere  110  assembled with the combination of the First MM Optical Fiber Patch Cord  150 , Mechanical Attenuator  170 , the First MM Optical Fiber Patch Card  129 , and a Current to Voltage Converter  127  is designed and is mounted inside a conventional integrating sphere which is equipped with the internal steel hemisphere  110  assembled with the Zr ferrule  140  of the First MM Optical Fiber Patch Cord  150  illustrated as in  FIG. 4  and  FIG. 5 , called Fiber Coupled Integrating Sphere  100  (FCIS) in the invention. The internal steel hemisphere  110  having an enclosed circular area of A sh =133 mm 2    520  in  FIG. 4  behaves as a target having a wide circular target area  520  of 133 mm 2 . Even though inner surface of the internal steel hemisphere  110  is chemically and mechanically polished/ mirrored, some portion of the intensive Pulsed Gaussian Laser Beams  501  of Pulsed Type laser Source  500 , Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600 , and CW Gaussian Laser Beam  799  of CW Laser Source  800  colliding inner surface of the internal steel hemisphere  110  is launched into the First MM Optical Fiber Patch Cord  150  through its Zr ferrule  140 , thanks to a relatively high numerical aperture of optical fiber of the First MM Optical Fiber Patch Cord  150 , the remaining diffuse reflectance characteristic and the inner surface curvature of internal steel hemisphere  110 , all of which provide a structural advantage for launching of some portion of Pulsed Gaussian Laser Beams  501 , Chopped Gaussian Laser Beams  601 , and CW Gaussian Laser Beam  799  into the core of Zr ferrule of the first MM optical fiber patch cord. If the intensity of the launched portion of Pulsed Gaussian Laser Beams  501  or Chopped Gaussian Laser Beams  601  or CW Gaussian Laser Beam  799 , which is detected by the Second Photodiode  129 , is insufficient, the coinciding process is performed by means of Alignment Combination  162  between the optical axis of Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800  and the Optical Axis  398  extending the center of the inner surface of the internal steel hemisphere on Port_ 3   103 . By this alignment process, the crests of Pulsed Gaussian Laser Beams  501 , Chopped Gaussian Laser Beams  601 , and CW Gaussian Laser Beam  799  entering from Port_ 1  through the Pin Hole  109  of 0.1 mm diameter at the center of the internal steel hemisphere on Port_ 3  are coincided on the same optical axis  398  and the maximizing process continues until the maximum intensity to be detected by the Second Photodiode  129  is available and is seen on the Oscilloscope  130  screen. As soon as the maximum intensity is obtained, and it is decided that the crests of Pulsed Gaussian Laser Beams  501 , Chopped Gaussian Laser Beams  601 , and CW Gaussian Laser Beam  799  entering from Port_ 1   101  directly collides to the center of the inner surface of the internal steel hemisphere  110  on which a Pin Hole  109  of  0 . 1  mm diameter is drilled. In this case, when I av    300 ,  842 , and I resp    200  measurements are performed by the combination of the First Photodiode  120  with the Electrometer  119 , the time/frequency related measurements of Pulsed Type Laser Source  500 , and Chopped Type Laser Source  600  are carried out by the combination of the Second Photodiode  129 , Current to Voltage Converter  127 , and Time Interval Counter  135  of FCIS based-LEMCS  111 . With this type of the configuration of the first MM fiber patch cord  150  and the second MM fiber patch cord  160  assembled with internal steel hemisphere  110  through Mechanical Attenuator  170 , the measurement reproducibility of photocurrent parameters I av    300 ,  842 , and I resp    200 , which are necessary for calculations of PE av    840 ,  845 , and  320 , is relatively enhanced for any relevant Gaussian type laser source, depending on the application in FCIS based-LEMCS such as, Pulsed Gaussian Laser Beams  501  of Pulsed Type laser Source  500 , Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600 , and CW Gaussian Laser Beam  799  of CW Laser Source  800 , because the same Optical Axis  398  is achieved by maximizing the photocurrent of the Second Photodiode  129  on the screen of the Oscilloscope  130 . The maximum photocurrent from the Second Photodiode  129  is obtained by adjusting Alignment Combination  162  in  FIG. 1 ,  FIG. 2 , and  FIG. 8  as soon as the peak irradiance position (crest) of the Pulsed Gaussian Laser Beams  501  of Pulsed Type Laser Source  500 , the Chopped Gaussian Laser Beam  601  of Chopped Type Laser Source  600 , and the CW Gaussian Laser Beam  799  of CW Laser Source  800  entering from Port_ 1   101  in FCIS  100  is matched with 62.5 μm core of Zr ferrule  140  of the First MM Optical Fiber Patch Cord  150  extending to the inner surface of internal steel hemisphere  110 . The tip of Zr ferrule  140  of the First MM Optical Fiber Patch Cord  150  is located back from the inner surface of the internal steel hemisphere  110  as 0.2 mm and that is, Zr ferrule  140  of the First MM Optical Fiber Patch Cord  150  is rest backward the center of the internal steel hemisphere  110 . In order to launch the Gaussian Laser Beams  501 ,  601 ,  799  into the First MM Optical Fiber Patch Cord  150 , a Pin Hole  109 , which is shown in  FIG. 4  and which has a diameter of 0.1 mm, is so drilled that the core of Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  is centered with this Pin Hole  109  and the Pulsed Gaussian Laser Beams  501  of Pulsed Type Laser Source  500 , Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600 , and CW Gaussian Laser Beam  799  of CW Laser Source  800  is first oriented to this Pin Hole  109  during PE av    840 ,  845 , and  320  measurements by means of Alignment Combination  162  by directly observing the relative output signal level of the Second Photodiode  129  linked to Current to Voltage Converter  127  on the screen of the Oscilloscope  130 . The maximum signal on the screen of the Oscilloscope  130  is P 0 ′  401  in  FIG. 3  during PE av    840 , and  845  measurements of Pulsed Type Laser Source  500 , and Chopped type Laser Source  600 , and the maximum signal on the screen of the Oscilloscope  130  is  198  for CW Laser Source  800  as in  FIG. 8  during the determination of  320 . In the invention, because Chopped Type Laser Source  600  is generated from CW Laser Sources  800  by using a series of choppers  901 - 909 , the optical axes coinciding process can be made directly by using CW Laser Source  800  without chopping CW Laser Gaussian Beams  799  just before measuring  842  and resultantly. This point is clarified in the Section “c-) Calibration of a Commercial Laser Energy Meter by using chopped type laser source”. The Gaussian Laser Beams  501 ,  601 ,  799  of Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800  reflected from the inner surface of the internal steel hemisphere  110  are repetitively reflected towards nearly same region of FCIS  100 , labeled as the first reflection  149  in  FIG. 4 , and this provides us with higher repeatability and reproducibility of optical axis alignment processes in measurements of I av    300 ,  842 , and I resp    200  yielding the results of PE av    840 ,  845 , and  320  together with the time/frequency related measurements T av    330 , f av    331 ,  844 , and  843  to be performed by the Second Photodiode  129 . T av    330 , f av    331  are related parameters to PE av    840 , which is the averaged pulse energy of Pulsed Type Laser Source  500 .  844 , and  843  are related parameters to  845 , which is the reference and averaged pulse energy of Chopped Type Laser Source to be used in the calibration of Commercial Laser Energy Meter  999 . For CW Laser Source  800  in  FIG. 8 , which has identical beam waist and divergence properties those stated in this invention, typically, an optic power of P cw   _   resp ≅4 mW  201  of CW Gaussian Laser Beam  799  of CW Laser Source  800  entering from Port_ 1   101  of FCIS  100 , and falling on the center of the internal steel hemisphere  110 , the launched optical power  198  in the First MM Optical Fiber Patch Cord  150  through Pin Hole  109  having a diameter of 0.1 mm stimulates a maximum DC voltage of 10 mV at the output of Current to Voltage Converter  127  joined to the Second Photodiode  129  as in  FIG. 8 , which is tracked on the screen of Oscilloscope  130  in real time and during all the measurements in the invention. This also corresponds to a pulse peak power P 0 ′ of 10 mV  401  for Pulsed Type Laser Source  500 , and Chopped Type Laser Source  600 . It is said that a maximum DC voltage ˜10 mV on the Oscilloscope  130  screen matching an optical power of P cw   _   resp ≅4 mW  201  corresponds typically to the best condition of the optical alignment between the optical axis of CW Laser Source  800  and the optical axis  398  of FCIS  100  of FCIS based-LEMCS  111  for the Port_ 1   101 , which is a circular aperture of 8 mm diameter in the invention. These typical values are given for how to operate the optical alignment procedure of FCIS based-LEMCS  111  in the invention. 
         [0113]    Internal steel hemisphere  110 , in the center of which Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  is placed, is inclined, i.e. 25°, towards the opposite wall of the First Photodiode  120  in order to prevent the First Photodiode  120  from the first reflections of Pulsed Gaussian Laser Beams  501  of Pulsed Type Laser Source  500  and Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600  falling onto the First Photodiode  120  as shown in  FIG. 4 . The diameter of the internal steel hemisphere  110  is 13 mm and the circular target area of the internal steel hemisphere  110  is A sh =π(13/2) 2 =133 mm 2    520 . Due to the fact that the internal steel hemisphere  110  is inclined as i.e.  25 ° towards the opposite wall of the First Photodiode  120 , the Gaussian Laser Beams  501 , 601 , 799  entering from Port_ 1   101  doesn&#39;t see an enclosed circular area of A sh =133 mm 2   520 . Instead of 133 mm 2 , Port_ 1   101  sees an effective circular area of 133 mm 2 ×cos (25°)=120.54 mm 2 . 
         [0114]    The inner surface of internal steel hemisphere  110  is mechanically and chemically polished/mirrored. The increasing of the reflectivity of the inner surface of internal steel hemisphere  110  with the polishing processes prevents the inner surface of internal steel hemisphere  110  from the temperature increase, to be caused by Pulsed Gaussian Laser Beam  501  of the Pulsed Type Laser Source  500  and Chopped Gaussian Laser Beam  601  of Chopped Type Laser Source  600 , interior surface of internal steel hemisphere  110 . The penetration dept of the electromagnetic energy the interior polished surface of internal steel hemisphere  110  is infinitesimal small and the electric fields of Pulsed Type Laser Source  500  and Chopped Type Laser Source  600  induces the surface electric charges an the infinitesimal small surface depth on the polished/mirrored surface of the internal steel hemisphere  110 . This directly corresponds to no electrical charge inside the internal steel hemisphere  110  and secondary electromagnetic waves are induced by the surface charges vibrating with an optical frequency identical to that of Pulsed Type Laser Source  500  and Chopped Type Laser Source  600 . The secondary wave propagation of the Pulsed Type Laser Source  500  and Chopped Type Laser Source  600  reflected from the interface air/internal steel hemisphere  110  inner surface and Zr ferrule  140 , the melting point of which is 1855° C., gives rise to a scattering wave and so is reflected to the opposite wall of the First Photodiode  120  inside FCIS  100  with the inclination of internal steel hemisphere  110 , i.e. 25° in the invention. The absorption of electromagnetic wave in a metal takes places in consistent with Paul Drude&#39;s model, based on the idea that free electrons first accelerated with electrical field of electromagnetic wave in the metal are damped with phonon collisions together with other lattice imperfections, and is strong functions of polarization of electromagnetic wave, incidence angle of beam, surface properties such as roughness, frequency of electromagnetic wave, electrical conductivity of the metal, and the temperature of the metal. In  FIG. 5 , the penetration depth is demonstrated by dark gray such as an evanescent wave penetration inside stainless steel. In three dimensional spaces, the absorbing volume of stainless steel can be regarded as a cone for the estimation of energy transferred into stainless steel body via way of heat conduction and the temperature increases inside stainless steel body of internal steel hemisphere  110 . In addition to Paul Drude&#39;s model, Fresnel Formulas, which are written for wavelength dependent p- and s-polarization states in terms of optical constant of the mentioned metal, also work for absorption properties of the mentioned metal surface. For visible and IR electromagnetic fields, the penetration depth of electromagnetic wave in the metal is approximately a few tenths of nanometer. However, the typical penetration depth, in which the electromagnetic energy is strongly absorbed, is assumed as the order of a few hundreds of nanometers by considering the surface roughness, the impurities, the oxide content, the surface temperature and the possible surface defects of the inner polished surface of internal steel hemisphere, all of which cause the incoming light beam of Pulsed Type Laser Source to be trapped inside metal body, giving rise to temperature increase inside the stainless steel body. Therefore the calculations in the invention, it can be assumed that the relevant laser energy is confined and absorbed within a few hundred nanometers of the inner surface of internal steel hemisphere taking the surface roughness and other affecting parameters mentioned above into account. For an IR laser of 980 nm, the penetration depth of 500 nm together with the surface roughness, the impurities, the oxide content, the surface temperature and the surface defects, which strongly affect the absorbance of the electromagnetic energy in the metal is a realistic approach, which is seen in the data obtained from atomic force microscope inspections and Monte Carlo Simulation results [6]. The “penetration depth” term stated in this part should be regarded as a confined volume of inner polished surface of internal steel hemisphere, in which any Pulsed Gaussian Laser Beam is strongly absorbed and is directly converted into temperature increase inside internal steel hemisphere. One of the critical point in this invention is to calculate the temperature increase in the confined volume of the internal steel hemisphere  110  which is enclosed by the beam size of the Pulsed Type Laser Source on the target point of the internal steel hemisphere and the penetration depth of 500 nm with some degree of surface roughness. The beam sizes of Pulsed Type Laser Source  500  and Chopped Type Laser Source  600  on the target of the internal steel hemisphere  110  corresponds to the base diameter of cone and it is calculated as 2.72 mm for 980 nm at the worst case. By assuming that the enclosed volume in body of internal steel hemisphere  110  is a cone volume, not a cylinder, the following calculations are carried out for the worst case and scenario. The maximum single pulse energy which corresponds to the maximum value of the pulse energy of Pulsed Type Laser Source  500 , is 100 mJ, the typical total (specular plus diffuse) reflectance of inner surface of internal steel hemisphere  110 , which is chemically and mechanically mirrored/polished, is 95% for near IR region of the electromagnetic spectrum. The melting point of stainless steel, the material of the internal steel hemisphere, is 1510° C. The specific gravity of stainless steel, from which the internal steel hemisphere  110  is manufactured, is 7850 kg/m 3 . The specific heat of stainless steel is 490 J/(kg K) and the thermal conductivity, a function of electron mobility inside metal, is 23 W/(m K). 
         [0115]               (16) 
         [0116]    The volume and the mass of the cone, in which electromagnetic field of Pulsed Type Laser Source  500  penetrates, is calculated as follows; 
         [0117]    ==           
         [0118]    For a single pulse of 100 mJ, the temperature increment is calculated by 
         [0119]               (17) 
         [0120]    The reflection of the mirrored surface of internal steel hemisphere  110  is ˜95%. In this case the absorbed energy by stainless steel for of 100 mJ is around 5 mJ. The temperature increment resulted from a absorbed energy of 5 mJ inside the enclosed cone volume of stainless steel is, 
         [0121]    
               
     
         [0122]    When the temperature increment of 1398 K caused by a of 100 mJ inside the enclosed cone volume in the body of the internal steel hemisphere  110 , this temperature increment is dissipated inside all steel body of the internal steel hemisphere  110 , the total mass of the internal steel hemisphere  110  13 g, and it has a surface area of 3.9 cm 2  (2.1 cm×1.85 cm and its thickness is 3 mm) behaving as a heat sink for the enclosed cone volume of the internal steel hemisphere  110 . The heat transfer from hotter region to the surrounding and cooler region inside the stainless steel body behaving as a heat sink for the enclosed cone volume of the internal steel hemisphere  110  takes places with electron mobility and so the average electron velocity is a determinative parameter for thermal conductivity. If the heat transfer rate by heat conduction process inside stainless steel of the internal steel hemisphere  110  is known, it is possible to calculate the time elapsed for decreasing the temperature increment of 1398 K to any reasonable temperature level not damaging the material and surface conditions of the internal steel hemisphere  110 . When the Pulsed Gaussian Beam of Pulsed Type Laser Source having a maximum pulse energy of 100 mJ collides on the stainless steel with a beam diameter of 2.72 mm of 980 nm laser by assuming the temperature of the internal steel hemisphere 110 is in thermal equilibrium for the room temperature of 25° C. equal to 298K, the temperature on the target diameter of 2.72 mm of the stainless steel reaches 298 K+1398K=1696 K, corresponding to 1423° C. The energy transfer rate with conduction in (j/s) is 
         [0123]               (J/s) (18) 
         [0124]    Where k is thermal conductivity of stainless steel and equal to 23 W/(m K). A is surface area of internal steel hemisphere  110  behaving as a heat sink, and equal to 3.9 cm 2  and x is the thickness of the stainless steel constituting the internal steel hemisphere and equal to 3 mm. is the temperature difference of stainless steel before and after heat dissipation. Now the instant temperature value on the target diameter of 2.72 mm of the stainless steel, once maximum single laser pulse energy of 100 mJ of Pulsed Type Laser Source falls, is 1423° C. A temperature difference of =1000 K can be reasonable value for not damaging the inner surface of the internal steel hemisphere  110 . From Eq. (18), the energy transfer rate with conduction inside the steel body of the internal steel hemisphere is =2990 J/s, and finally the energy of 5 mJ absorbed by stainless steel is dissipated within (5 (mJ)/2990 (J/s)=1.7 μs) in body of the internal steel hemisphere  110 . The whole mass of the internal steel hemisphere  110  is 13 g and the temperature increase inside whole body of the internal steel hemisphere  110  can be estimated as in Eq. (19) by assuming that the temperature gradient is uniformly distributed inside the volume of the internal steel hemisphere  110 , 
         [0125]               (19) 
         [0126]    The volume of the stainless steel behaving as a heat sink is equal to multiplication of the surface area of 3.9 cm 2  (2.1 cm×1.85 cm) with the thickness of 3 mm, yielding 1.17 cm 3 . The mass behaving as a heat sink is obtained by multiplying 1.17 cm 3  with stainless steel specific gravity, 7850 kg/m 3 , yielding=9.1845 g. 
         [0127]               (20) 
         [0128]    It should be remembered that 5 mJ is directly corresponds to a pulse energy of 100 mJ because of the averaged reflectivity of 95% of the mirrored inner surface of internal steel hemisphere  110 . Resultantly, temperature increase is for each laser pulse, of which is 100 mJ. The result inferred from these calculations the internal steel hemisphere easily withstand the laser pulse train composed of the maximum single laser pulse energies up to =100 mJ without any degradation, if the dead time DT  312  is wider than 1.7 μs between two adjacent laser pulses, of which is 100 mJ . If the dead time DT  312  between two adjacent pulses in  FIG. 3 , each of which has a of 100 mJ, is narrower than 1.7 μ, this doesn&#39;t allow the single pulse energy inside the body of internal steel hemisphere  110  behaving as a heat sink to dissipate sufficiently. In other words, to apply any pulse train having the dead time DT  312 , which is narrower than 1.7 μs, between two adjacent pulses, each of which has a of 100 mJ, increases the instant temperature of the body of the internal steel hemisphere  110 , as a function of repetition frequency of Pulsed Type Laser Source  500 . On the other hand, if it is assumed that Pulsed Type Laser Source has a repetition frequency of 1 MHz and it has a of 100 mJ, which matches a peak power P 0    400  of 200 kW for PW  310 =0.5 μs, this is equal to 500,000 pulses per 1 sec (five hundred thousand pulses), in this case of Dead Time (DT  312 )=0.5 μs&lt;1.7 μs, the temperature increases quickly inside the volume of the stainless steel behaving as a heat sink and approaches to 500,000×=550 K for pulse application of 1 s, which is the worst case. When the pulse energy increases, it is necessary to make DT  312  between two adjacent laser pulses be larger than 1.7 μs so as to obtain sufficient heat dissipation. However it should be remembered that the maximum average power, which corresponds to the maximum value of the averaged optical power P av    301  in  FIG. 3 , which enters from the Port_ 1   101  of FCIS  100 , and which corresponds to the saturation power for the First Photodiode  120  of 7 mW, should be ≅158 W, which is a value from the ration of the active area of the First Photodiode  120  to the inner surface area of 4πR 2  of FCIS  100 . In this case in order to measure to the peak power P 0    400  of 200 kW via FCIS without saturation of the First Photodiode, the pulse width (PW  310 ) of the peak power P 0    400  of 200 kW should be 1.35 ns and the dead time (DT  312 ) should be any value wider than 1.7 μs for sufficient heat dissipation inside stainless steel body. However, it is seen from Eq. (9), and Eq. (10), the rise time of the First Photodiode is 1 MHz and as a consequence, 1.35 ns pulse having a peak power P 0 =200 kW  400  cannot be detected by the First Photodiode  120  owing to the pulse response limit of 0.736 μs of the First Photodiode  120  in Eq. (9). 
         [0129]    NOTE: The above calculations regarding time duration,—which is pulse dead time (DT) of infinite laser pulse train,—necessary for the sufficient dissipation of the absorbed heat resulted from the temperature increase, which is caused by the maximum pulse energy of Pulsed Gaussian Laser Beam of Pulsed Type Laser Source, inside the body of internal steel hemisphere used as a target in the invention are to give an exact method for the question of how to calculate time duration (dead time-DT) between two adjacent pulses, each of which has a maximum single pulse energy of 100 mJ, during the application of maximum single pulse energy of 100 mJ, without damage on the inner surface of internal steel hemisphere. Reflectance, penetration depth, surface roughness, temperature of metal surface, specific heat of metal may change within very wide range, as well as electromagnetic wave properties such as wavelength, incident angle and its state of polarization. Any change in the numerical values of these parameters that strongly affect the above calculations doesn&#39;t disturb the philosophy of the invention, the correctness of the above calculations and the presented method 
         [0130]    Now here we can construct the correct limit conditions for the FCIS based-LEMCS  111  for the parameters belonging to Pulsed Type Laser Source. The parameter here are averaged values: which is the minimum value of PW av    342 ; which is the maximum value of PW av    342 ; , which is the minimum value of DT av    340 ; which is the minimum value of T av    330 ; which is the saturation value of P av    301  for the First Photodiode  120 ; and which is the maximum value of P 0    400  of the maximum peak power of either Pulsed Type Laser Source in  FIG. 3 : According to the assessments given just below Eq. (9), should be equal to or larger than 736 ns for time response of the First Photodiode, should be equal to or larger than 1.7 μs for sufficient heat dissipation at the maximum pulse energy of 100 mJ from the above evaluations together with those in FIG. ( 4 ). Finally, the maximum averaged saturation power, which can be measured by FCIS based-LEMCS  111  without saturation of the First Photodiode  120  is calculated as 158 W from the surface ratios of FCIS  100  interior surface area and active area of the First Photodiode  120 . Resultantly, by using Eq. (4) for an infinite laser pulse train having a period of =0.736 μs +1.7 μs=2.436 μs and we can calculate the maximum peak power to be measured through FCIS based-LEMCS  111  for an infinite laser pulse train having an averaged Duty Cycle av    299  as in Eq. (5), 
         [0131]               (21) 
         [0132]    An infinite laser pulse train having a maximum peak power =522 W calculated from Eq. (21), the of which is 0.736 μs and the of which is 1.7 μs creates an averaged pulse energy PE av    840  of ˜384 μJ on FCIS based-LEMCS  111  and it can be measured without damage on internal steel hemisphere surface and without saturation of the First Photodiode. 
         [0133]    For the maximum averaged pulse energy of 100 mJ of FCIS based-LEMCS  111 , the maximum pulse width for the maximum peak power of 522 W of Pulsed Type Laser Source, which can be detected by the First Photodiode  120  without saturation, is calculated by dividing 100 mJ with =522 W and the result is 1.9×10 −4  s. 
         [0134]    In brief, the ultimate limit parameters for measuring the averaged pulse energy of Pulsed Type Laser Source  500 , which FCIS based-LEMCS  111  in the invention can measure, are summarized as minimum averaged pulse width, ≅0.736 μs, averaged minimum dead time, ≅1.7 μs, producing a minimum repetition period of ≅2.436 μs, corresponding to an averaged repetition frequency of           410509 Hz and the maximum pulse width, ≅1.9×10 −4    40  s for a maximum peak power ≅ 522  W, which can be detected by the First Photodiode without saturation and the averaged saturation power for the First Photodiode  120  is          . 
         [0135]    Mechanical Attenuator  170 , which is joined to the ceramic ferrule of FC/PC connector of the first MM optical fiber patch cord  120 , is used to attenuate the some portion of the Pulsed Gaussian Laser Beam  501  launched into Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  assembled with internal steel hemisphere  110 . In this invention, although the limited numerical aperture of 0.25 rad of the optical fiber core of Zr ferrule  140  of the First MM Optical Fiber Patch Cord  150  inherently protects the Second Photodiode  129 , a Mechanical Attenuator  170  is also engaged for an additional protection of the Second Photodiode  129  against high level of optical power exposure during time and frequency measurements of the Pulse Type Laser Sources  500  having a relatively high peak power. Due to the fact that the Second Photodiode  129  is only used for time/frequency related measurements, Mechanical Attenuator  170  is kept on high attenuation position. High attenuation position of Mechanical Attenuator  170  is reduced to low attenuation position by observing the voltage on the screen of the Oscilloscope  130 , PE av (f av )  840  value of which is to be measured, until the pulse levels of Pulsed Type Laser Source  500  are seen on the screen of the Oscilloscope  130 . When the sufficient pulse level is seen on the screen of the Oscilloscope  130 , the averaged repetition period T av    330  and the averaged repetition frequency f av    331  of Pulsed Type Laser Source in Eq. (16) are measured directly by the combination of the Second Photodiode  129 , Current to Voltage Converter  127 , and Time Interval Counter  135  in  FIG. 1 , which is calibrated traceable to  133 Cs (or  87 Rb) Atomic Frequency Standard  804 , in average mode. 
         [0136]    The Second Photodiode  129  is used for the time measurements, cutoff limit is 6 GHz and the cutoff limit of the successive Current to Voltage Converter  127  is 10 GHz. Because FCIS based-LEMCS  111  described in this invention is one embodiment, the upper cutoff frequencies are acceptable and better than 1 MHz and 6 GHz for both photodiodes designated as the First Photodiode  120  and the Second Photodiode  129 . Additionally, both photodiodes called as the First Photodiode  120  and the Second Photodiode  129  herein can be exchanged with different types of semiconductor detector depending on the spectral power distribution of the laser in the application. Types of CW Laser Sources  800  which are used for constructing Chopped Type Laser Sources  600 , generating the reference and averaged pulse energy  845 , in FCIS based-LEMCS  111 , which is to be engaged in the traceable calibration of Commercial Laser Energy Meters  999 , are not included in the invention. However, the compatibilities and the dimensional relationships of the following parameters in terms of their sizes, and their locations together with the measurement and the calibration methods to be explained in Section “3. Measurement Method of pulse energy of Pulsed Type Laser Source and calibration of Commercial Laser Energy Meter by FCIS based-LEMCS” are included in the invention. The compatibilities and the dimensional correlations to be included in the invention, which are the additions to the three main ideas/items given at the end of “DESCRIPTION” section, are; 
         [0137]    a-) the geometrical dimension of Port_ 1   101  with respect to full sizes of beam of Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800  entering from Port_ 1   101 , and their beam waists, 
         [0138]    b-) beam divergences of Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800  starting from z=0, depending on the distance on the Optical Axis  398  with respect to size and location of the internal steel hemisphere  110 , 
         [0139]    c-) the size of internal steel hemisphere  110  with respect to the size and dimension of FCIS  100  of FCIS based-LEMCS  111 , its angular inclination and its position with respect to Port_ 2   102 , 
         [0140]    d-) the position of Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Card  150  assembled with the internal steel hemisphere  110  at Port_ 3  with respect to position of Port_ 1   101  for Pulsed Gaussian Laser Beam  501 , Chopped Gaussian Laser Beam  601 . and CW Gaussian Laser Beam  799  beam entering from Port_ 1   101  and having the calculated beam divergences. 
         [0141]    2. Details of Choppers 
         [0142]    A series of the choppers  901 - 909  of FCIS based-LEMCS  111  invented are used for constructing Chopped Type Laser Source  600  generating the reference and averaged pulse energies  845  for the calibration of Commercial Laser Energy Meters  999  traceable to primary level standards by chopping the CW Gaussian Laser Beams  799  of CW Laser Sources  800  in  FIG. 2 . which are called the first CW Laser_ 1 , the second CW Laser_ 2 , the third CW Laser_ 3 , and the fourth CW Laser_ 4 . These CW Laser Sources  800 , at same time, are operated in the determination of the spectral responsivity  320  of FCIS  100  of FCIS based-LEMCS  111  in CW regime/mode, shown in  FIG. 8 . With the choppers  901 - 909  used in this invention, the CW Gaussian Laser Beams  799  of the first CW Laser_ 1 , the second CW Laser_ 2 , the third CW Laser_ 3 , and the fourth CW Laser_ 4  are chopped with variable Duty Cycles  322 . The Duty Cycles changing from 0.17 to 0.84 via DC Motor  599  having High Quality Rare Earth Doped Magnet are obtained for the repetition frequencies  321  (f=1/T), from 5 Hz to 2 kHz in the calibration of Commercial Laser Energy Meter  999  against FCIS based-LEMCS  111  in  FIG. 2 . The adjustment of Duty Cycle continues up to 2 kHz via a DC Motor  599 . Modulation frequency depends on the angular rate generated by the DC motor and the Duty Cycle  322  at any modulation frequency generated via DC Motor  599  relies on the angular slit of any chopper joined to DC Motor  599 . The combination of the explained choppers  901 - 909 , CW Laser Sources  800  and DC Motor  599  having High Quality Rare Earth Doped Magnet in FCIS based-LEMCS  111  forms the infinite laser pulses having stable pulse energies stated as the reference and averaged pulse energy  845  for calibrating Commercial Laser Energy Meters  999  in  FIG. 2  and N is equal to 1 for the infinite laser pulses in time domain. 
         [0143]    In this invention, the different repetition periods T(s)  320  of the chopped Gaussian Laser Beams having an Duty Cycles  299  varying 0.17 to 0.84 are generated, these repetition periods T(s)  320  are precisely measured by removing the negative effects of time constant of FCIS  100  and the relatively lower cutoff frequency of the First Photodiode  120  by means of new placement type of the Second Photodiode  129  mounted to the FCIS  100 . Finally a new method and a new configuration of integrating sphere, called FCIS in this invention, are put into progress to calibrate the pulse energy PE clem (J) scales of the Commercial Laser Energy Meters  999 . 
         [0144]    The chopper  901 - 909  details used in FCIS based-LEMCS  111  are given in the drawings separately, from  FIG. 6 a    to  FIG. 6 b   . The metal coppers  901 - 909  used in this invention are made from stainless steel and engraved by means of a computer controlled-laser cutting machine with high precision. The choppers  901 - 909  are so designed that they have 15 periods in one complete turn and each period is 24°. The full diameter of each chopper  901 - 909  is 106 mm, the thickness of each chopper  901 - 909  is 1 mm. The closed section of the chopper  901 - 909  generating a Duty Cycle  322  of 0.83 in  FIG. 6 a    is so designed and engraved that the CW Gaussian Laser Beam  799 , which has a beam waist of 2.8 mm at z=0, corresponding to the widest beam waist used herein, is completely blocked. The averaged Duty Cycle is Duty Cycle av    299  measured as an averaged value by Time Interval Counter  130  and it is considered as time/frequency related measurements in the invention. The open section of the chopper  901 - 909  generating a Duty Cycle  322  of 0.17 in  FIG. 6 b    is so designed and engraved that the CW Gaussian Laser Beam  799 , which has a beam waist of 2.8 mm at z=0, is completely passed. With this mechanical chopping process, the zero level of Chopped Gaussian laser beam, the  845  of which is to be measured, is exactly generated and as a result, the leakage (background) current in  842  caused by exactly not zeroing the optical power to be entered in FCIS  100  of FCIS based-LEMCS  111  is prevented and the undesired contribution at the leakage (background) current in  842 , which electronic modulation may cause this type error because of the insufficient reversed bias, is removed for each Duty Cycle  322  at any averaged repetition frequency  843  and this uncertainty source is disregarded with mechanical chopping processes, generated by the choppers detailed in drawings referred as  FIG. 6 a    and  FIG. 6 b   . If an electronic modulator is used for applying pulse modulation to any laser operating in CW regime/mode, the zero level of the Pulsed Gaussian Laser Beams  501  should be considered and subtracted in the calculation as a background (leakage current). If this background (leakage) current level due to not zeroing the output of modulated Gaussian laser beams with the electronic modulation is not considered, it causes wrong pulse energy calculations and it increases the measurement uncertainty in the calibration of Commercial Laser Energy Meter  999 . However, the use of a series of the chopper  901 - 909  in producing the Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600  in this invention prevents the problematic and the undesired condition and reduces the measurement uncertainty caused by not getting zero level. 
         [0145]    Jitter of the DC Motor  599 , to which the choppers  901 - 909  is mounted as in  FIG. 2 , and which has a rare earth doped magnet, has an RMS value of 0.2° at 1 KHz. This value is obtained, comparing a reference frequency of 1 KHz with the Chopped Gaussian Laser Beams  601  coming from the chopper having 0.5 Duty Cycle  322 , by Time Interval Counter  130 . For the constant peak power P 0    400  of the Chopped Gaussian Laser Beam  601  as in  FIG. 3 , the maximum and minimum pulse energy to be generated by means of the chopper configuration, depending on the repetition frequency f(Hz)  321 , the repetition period T(s)  320 , dead time DT(s)  312 , pulse width PW(s)  310 , and Duty Cycle  322  in the invention are given at the following. 
         [0146]    The repetition frequency f (Hz)  321  range, over which Commercial Laser Energy Meters  999  are calibrated in FCIS based-LEMCS  111  in this invention extends from 5 Hz to 2 kHz by means of the nine separate choppers for the Duty Cycle  322  ranges 0.17 to 0.83 shown in  FIG. 6 a   . and  FIG. 6 b   . In this case the maximum energy via these choppers  901 - 909  to be engaged in the calibration of Commercial Laser Energy Meter  999  in FCIS based-LEMCS is calculated as follows. Superscript “_clem” shows the relevant parameter in the calibration of Commercial Laser Energy Meter  999 . 
         [0147]    For the repetition frequencies f (Hz)  321  which corresponds to the averaged repetition frequency f av    331 , in Eq. (16); 
         [0148]               (J) (22) 
         [0149]    In order to produce the maximum energy for the constant peak power P 0    400  by means of the combination of one of the choppers  901 - 909  and DC Motor  599  in the invention, the maximum pulse width PW ref   _   clem   _   max  corresponding to the minimum repetition frequency at maximum duty cycle Duty Cycle ref   _   clem   _   max  should be adjusted and in the case of maximum pulse width PW ref   _   clem   _   max  ,  842  is obtained as the maximum photocurrent in the First Photodiode  120  of FCIS  100 . According to CW Laser Source  800  used in this invention which corresponds to the minimum value of  320 , is equal to the spectral responsivity of FCIS  100  at 980 nm, which is changeable value from application to application. 
         [0150]               (Hz) (23) 
         [0151]    In this invention the minimum repetition frequency Hz, corresponding the maximum repetition period=200 ms and Duty Cycle ref   _   clem   _   max =0.83 for the chopper  901  given in  FIG. 6 a   , the corresponding the maximum pulse width. The final equation for Eq. (22) is 
         [0152]               (J) (24) 
         [0153]    Minimum energy for these choppers  901 - 909  to be engaged in the calibration of Commercial Laser Energy Meter  999  in FCIS based-LEMCS  111  is calculated as follows; 
         [0154]    For the averaged repetition frequencies f (Hz)  321 , which corresponds to the averaged repetition frequency f av    331 , in Eq. (16); 
         [0155]               (J) (25) 
         [0156]    In order to produce the minimum energy for the constant peak power P 0    400  by means of the combination of one of the choppers  901 - 909  and DC Motor  599  in the invention, the minimum pulse width PW ref   _   clem   _   min  corresponding to the maximum repetition frequency at the minimum duty cycle should be adjusted and in the case of the minimum pulse width PW ref   _   clem   _   min ,  842  is obtained as the minimum in the First Photodiode  120  of FCIS  100 . According to CW Laser Source  800  used in this invention, which corresponds to the maximum value of  320 , is equal to the spectral responsivity of FCIS  100  at 1549 nm, which is changeable value from application to application. 
         [0157]               (Hz) (26) 
         [0158]    In this invention the maximum repetition frequency kHz, corresponding minimum repetition period=0.5 ms and Duty Cycle ref   _   clem   _   min =0.17 for the chopper  909  given in  FIG. 6 b   , the corresponding the minimum pulse width. The final equation for Eq. (25) is, 
         [0159]               (J) (27) 
         [0160]    In order to protect the operator from the laser beam reflected the closed section of the relevant chopper  901 - 909 , the suitable protection equipments for both body and eye safety should be used. 
         [0161]    The changing of these values presented here doesn&#39;t disturb the philosophy of this invention because FCIS based-LEMCS  111  together with the methods to be described in the below Section 3 against FCIS based-LEMCS  111  traceable to primary level standards constitutes one embodiment. 
         [0162]    3. Measurement Method of pulse energy of Pulsed Type Laser Source and calibration of Commercial Laser Energy Meter by FCIS based-LEMCS 
         [0163]    This section comprises the following parts; 
         [0164]    The section “Determination of the spectral responsivity of FCIS based-LEMCS” describes the method of determining the spectral responsivity  320  of FCIS  100  of FCIS based-LEMCS with respect to the Optical Power Transfer Standard  809  calibrated against Cryogenic Radiometer  803  in near IR region by using CW Gaussian laser beam  799  of CW Laser Source  800  in  FIG. 8 . 
         [0165]    The section “Method of measuring the averaged pulse energy PE av  of a Pulsed Type Laser Source by means of FCIS based-LEMS” describes the method of measuring the averaged pulse energy PE av    840  with pulsed Gaussian laser beams of a Pulsed Type Laser Source  500  emitting in near IR region covering the spectral range in the invention, in which the spectral responsivity  320  of FCIS  100  of FCIS based-LEMCS  111  is determined, in  FIG. 1 . Due to the fact that the FCIS based-LEMCS  111  is constructed as one embodiment, the changing in the spectral region specified as near IR above doesn&#39;t change the philosophy of the invention. 
         [0166]    The section “Calibration of a Commercial Laser Energy Meter by using Chopped Type Laser Source in FCIS based-LEMS” describes how to calibrate any Commercial Laser Energy Meter against the chopped Gaussian laser beams  601  of Chopped Type Laser Source  600  generated by means of the combination of CW Laser with the nine separate choppers as an infinite wave train, the averaged pulse energy  845  of which was measured by FCIS based-LEMCS, generating a calibration factor called γ  945  as in  FIG. 2 . These methods described in this section are included in this invention. 
         [0167]    a-) Determination of the spectral responsivity of FCIS based-LEMCS; 
         [0168]    In this invention, in order to determine the averaged pulse energy PE av    840  of Pulsed Type Laser Source  500  and to determine the averaged pulse energy  845  of Chopped Type Laser Source  600 , the configurations of FCIS based-LEMCSM illustrated in  FIG. 1  and  FIG. 2  are used for directly measuring the average photocurrents I av    300  and  842  related to the averaged pulse energies  840  and  845  emerging from the Pulsed Type Laser Source  500  and Chopped Type Laser Source  600  by means of the First Photodiode  120  in turn, and are used for directly measuring the average repetition periods T av    330  and  844  and the average repetition frequencies f av    331  and  843  of Pulsed Type Laser Source  500 , and Chopped Type Laser Source  600  by means of the Second Photodiode  129  of FCIS  100  of FCIS based-LEMCS  111 . In order to calculate the pulse energies of Pulsed Type Laser Source  500 , and Chopped Type Laser Source  600 , the spectral responsivity  320  of FCIS  100  of FCIS based-LEMCS  111  assembled with the First Photodiode  120  is required. For a continuous type laser designated as CW Laser Source  800  herein, meaning not modulated in time domain and so not containing no additional frequency component related to the modulation in time domain, the average optical power is the same as its peak power and the same case is valid for the average photocurrent and the peak photocurrent as well. After this brief and repeated evaluation, the determination of spectral responsivity  320  of the First Photodiode  120  of FCIS based-LEMCS is accomplished with the configuration in  FIG. 7 . Superscript “resp” shows the relevant parameter in the determination of spectral responsivity  320  of FCIS  100  of FCIS based-LEMCS. 
         [0169]    In determination of the setup of FCIS based-LEMCS shown in  FIG. 8  is configured. The CW Gaussian laser beam  799  of CW Laser Source  800  is not chopped, and the optical power of CW Laser Source P cw   _   resp    201  directly is fallen in FCIS  100  in the continuous regime (CW). In this condition, FCIS  100  of FCIS based-LEMCS works as a conventional integrating sphere, except for internal steel hemisphere assembled with the Second Photodiode designed in the invention. The First Photodiode  120  produces the photocurrent I resp  (A)  200  proportional to the optical power of CW Laser Source P cw   _   resp  (W)  201 , which is measured by means of Optical Power Transfer Standard  809 . I resp  (A)  200  measured by the First Photodiode  120  is traceable to DC Josephson Voltage System  801  and Quantum Flail Resistance System  802  through Electrometer  119  shown as in  FIG. 7  and  FIG. 8 . The same CW Gaussian laser beam  799  of CW Laser Source  800  is fallen onto Optical Power Transfer Standard  809  shown in  FIG. 8  and  FIG. 7 , and then (W) is obtained as a traceable to Cryogenic Radiometer  803  in  FIG. 7 . Resultantly, the derived spectral responsivity of FCIS based-LEMCS  320  is fully traceable to primary level standards.  320  is the spectral response of the First Photodiode  120  in FCIS  100  of FCIS based-LEMCS  111 . The Second Photodiode  129  of FCIS  100  of FCIS based-LEMCS  111 , which is mainly used for measuring the time related measurements, and which sees Port_ 1   101  in directly opposite position, is also used for coinciding the input laser beams on the same optical axis with respect to the Pin Hole  109  at the center of internal steel hemisphere  110  settled on Port_ 3   103  axis in different measurements. With this type of configuration of the Second Photodiode  129  in the invention, in addition to time related measurements in the calculations of and, the highly repetitive measurements in the determination of spectral responsivity  320 , and the average photocurrents I av    300  and  842  related to the averaged pulse energies  840  and  845  are obtained because the input laser beams are collided on the Pin Hole  109  at the center of internal steel hemisphere  110  by tracking and maximizing the signal of the Second Photodiode on the Oscilloscope  130  screen for Gaussian Laser Beams  501 / 601  of Pulsed Type Laser Source  500 , Chopped Type Laser Source  600 , and CW Laser Source  800 . The Second Photodiode  129  in the determination of the spectral responsivity  320  of FCIS based-LEMCS is only engaged for identical optical alignment of CW Laser Source  800  towards inside of FCIS on the same optical beam path as in  FIG. 8 . The details of determining the spectral responsivity  320  of FCIS based-LEMCS are given in the following in item by item manner for easy understanding the process. In the numbering showing the steps to be applied, “a” shows that this measurement series belongs to “a-) Determination of the spectral responsivity of FOS based-LEMCS” and numbers as 1, 2, and etc. shows the sequence number of the steps being applied. 
         [0170]    a-1) First, CW Laser Source  800  lasing at wavelength λ (nm) given in  FIG. 8  is run with a rated power of 10 mW and the CW Gaussian laser beam  799  of CW Laser Source  800  is oriented to Port_ 1  of FCIS of FCIS based-LEMCS. The output powers of CW Laser Sources  800  are reduced to a few mW level by using neutral density filters to guarantee eye safety together with eye protection equipments in optical alignment, the optical densities of which extends to 2.5, which are located in front of the collimators at z=0. 
         [0171]    a-2) By using an IR viewer card having a compatible spectral range with that of CW Laser Source  800 , the CW Gaussian Laser Beam  799  of CW Laser Source  800  is centered on Port_ 1 . The compatibilities and the relationships among the beam waists, the size of Port_ 1   101 , and the size of internal steel hemisphere, emphasized in “Details of FCIS” subsection of “DESCRIPTION” section, is taken into account in this step. 
         [0172]    a-3) The centered CW Gaussian Laser Beam  799  of CW Laser Source  800  at Port_ 1   101  is fallen onto the internal steel hemisphere on Port_ 3  by adjusting the Alignment Combination in  FIG. 8 . 
         [0173]    a-4) As soon as the CW Gaussian Laser Beam  799  entering from Port_ 1   101  is fallen on the internal steel hemisphere  110 , the inner diameter of which is 13 mm shown as in  FIG. 3 , the Second Photodiode  129  assembled with the internal steel hemisphere  110  on Port_ 3   103  starts to detect the optical flux launched into the core of Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  through Pin Hole  109  due to inner curvature structure of internal steel hemisphere  110 . 
         [0174]    a-5) The hemisphere structure of the internal steel hemisphere  110  in the invention enables the CW Gaussian Laser Beam  799  being captured by a 0.25 rad numerical aperture of the core of Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150 . 
         [0175]    a-6) The photocurrent generated by the Second Photodiode  129 , transformed into voltage by means of Current to Voltage Converter  127  in  FIG. 8  and the output voltage of Current to Voltage Converter  127  is maximized in real time by adjusting the Alignment Combination in  FIG. 8 . The maximum output voltage is obtained when the maximum irradiance level of CW Gaussian laser beam  799  of CW Laser Source  800  is coincided with Pin Hole  109  of 0.1 mm detailed in  FIG. 4 . 
         [0176]    a-7) With this process described in this invention, the measurement reproducibility for the different measurements is enhanced because the crest corresponding to the maximum irradiance level of CW Gaussian Laser Beam  799  of CW Laser Source  800  entering from Port_ 1  is targeted on the same point defined by the Pin Hole  109  of 0.1 mm, back of which 62.5 with diameter core the core of Zr ferrule  140  of HMS type connector  132  of the First MM Optical Fiber Patch Card  150  is rest I placed, by maximizing the output voltage of Current to Voltage Converter  127  combined to the Second Photodiode  129  on Port_ 3  on the screen of the Oscilloscope  130  in real time. 
         [0177]    a-8) In the condition of the maximum output voltage of Current to Voltage Converter  127 , which corresponds to the Second Photodiode  129  detects the crest of the CW Gaussian Laser Beam  799  of CW Laser Source  800 , the photocurrent I resp (A)  200  generated by the First Photodiode  120  is read out proportional to the power P cw   _   resp  (λ)  201  of CW Laser Source  800  lasing at wavelength λ (nm) by means of Electrometer  119 . 
         [0178]    a-9) After obtaining the photocurrent I resp  (A)  200  generated by the First Photodiode, the same CW Gaussian Laser Beam  799  of CW Laser Source  800  is applied to Optical Power Transfer Standard  809  by substituting Optical Power Transfer Standard  809  for FCIS based-LEMCS. With this application, the optical power P cw   _   resp (λ)  201  of CW Laser Source  800  for wavelength λ (nm) is obtained from Optical Power Transfer Standard  809 , traceable to CR  803 , in W. 
         [0179]    a-10) These steps are repeated for the remaining of CW Laser Source  800  and the spectral responsivities of FCIS  100  of FCIS based-LEMCS are calculated by proportioning I resp  (A)  200  to P cw   _   resp  (W)  201  as (A/W)  320  to be used in the calculations of PE av    840  and  845  in according to Eq. (16). In this invention, four CW Laser Sources  800  are used, but any change in the number, wavelength, spectral bandwidth, and similar characteristics of lasers used in the invention doesn&#39;t change the philosophy of the invention. Different lasers can be used. 
         [0180]    a-11) The results of spectral responsivity (A/W)  320  of FCIS  100  of FCIS based-LEMCS  111  described in this invention together with the related partial uncertainties are given below; 
         [0181]              ; at 980.0 nm 
         [0182]              ; at 1064.0 nm 
         [0183]              ; at 1309.0 nm 
         [0184]              ; at 1549.0 nm 
         [0185]    Any change in these results introduced here doesn&#39;t change the philosophy of the invention because the FCIS based-LEMCS together with the methods described in the Section 3 is one embodiment. These spectral responsivities (A/W)  320  are used in the calculations of the averaged pulse energies PE av    840  and  845  of Pulsed Type Laser Source, and Chopped Type Laser Source, generating infinite pulse train in time domain, the wavelengths of which are conform to these wavelengths 980.0 nm, 1064.0 mu, 1309.0 nm, and 1549.0 nm, according to Eq. (16). Typical relative standard (combined) uncertainty is calculated as 0.80% (k=1) from the measurement series related to the determination of the spectral responsivity (A/W)  320  of FCIS  100  of FCIS based-LEMCS  111 , which includes the all the uncertainty components coming from the calibrations of the transfer standards calibrated against these primary level standards in  FIG. 7  as well as the individual uncertainties of the primary level standards in  FIG. 7 . 
         [0186]    b-) Method of measuring the averaged pulse energy PE av  of a Pulsed Type Laser Source by means of FCIS based-LEMCS; 
         [0187]    After completion of determination the spectral responsivities (A/W)  320  of FCIS  100  of FCIS based-LEMCS  111  performed according to the sequential steps specified in the above section of “Determination of the spectral responsivity of FCIS based-LEMCS”, the main configuration depicted in  FIG. 1  is considered, which is the main configuration of this invention to measure the averaged pulse energy of a Pulsed Type Laser Source  500  as a function of the repetition frequency f av    331 . In order to measure the averaged pulse energy of Pulsed Type Laser Source by using FCIS based-LEMCS, Pulsed Type Laser Source  500  instead of Chopped type Laser Source  600  depicted in  FIG. 2  is placed opposite Port_ 1   101  of FCIS  100  of FCIS based-LEMCS  111 . According to Eq. (16), the pulse energy related parameters of  320 , T av    330 , f av    331  and I av    300  should be measured.  320  is determined by the sequential steps given in the section of “Determination of the spectral responsivity of FCIS based-LEMCS”. The remaining parameters of the averaged pulse energy PE av  (J)  840  in Eq. (16), which are I av    300 , f av    331 , f av    331 , I av    300 , are directly measured by FCIS based-LEMCS designed in this invention and the operation steps to measure these parameters of the Pulsed Type Laser Source are introduced as the sequential operation steps at the following. In the measurement of the averaged pulse energy PE av (J)  840  of Pulsed Type Laser Source  500 : 
         [0188]    If the spectra of Pulsed Type Laser Source  500 , the averaged pulse energy PE av    840  of which is to be measured by FCIS based-LEMCS  111 , is different from  320  determined by the steps stated in the section of “Determination of the spectral responsivity of FCIS based-LEMCS”, a suitable fitting programs to make interpolation is engaged by taking the spectral responsivity  320  of the First Photodiode  120  mounted to FCIS  100  into account. 
         [0189]    The First Photodiode  120  mounted on Port_ 2   102  of FCIS based-LEMCS  111  is used for measuring I av    300 , corresponding to P av    301  of the pulsed type laser source. 
         [0190]    The Second Photodiode  129  assembled with internal steel hemisphere  110  and mounted on Port_ 3   103  of FCIS based-LEMCS  111  is used for measuring the averaged repetition period T av    330 , the averaged repetition frequency f av    331 , and number of pulses N of Pulsed Type Laser Source  500 , which is considered in a burst type laser source, and it is N=1 for infinite pulse train having constant repetition period T(s)  320 . In this invention N=1 for Pulsed Type Laser Source  500  producing infinite laser pulse train in time domain. 
         [0191]    The Second Photodiode  129  assembled with internal steel hemisphere  110  and mounted on Port_ 3   103  of FCIS of FCIS based-LEMCS, in addition to time/frequency related measurements, is also used for alignment of Pulsed Gaussian Laser Beam  501  of Pulsed Type Laser Source  500  entering from Port_ 1   101  is targeted on the same point defined by the Pin Hole  109  of 0.1 mm, back of which 62.5 μm diameter core of Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  is located, by maximizing the output voltage of Current to Voltage Converter  127  combined to the Second Photodiode  129  on Port_ 3   103  on the screen of the Oscilloscope  130  in real time. 
         [0192]    In the numbering showing the steps to be applied, “b” shows that this measurement series belongs to the section of “b-) Method of measuring the averaged pulse energy PE av  of a Pulsed Type Laser Source by means of FCIS based-LEMCS” and numbers as 1, 2, and etc. shows the sequence number of the steps being applied. 
         [0193]    b-1) First, Chopped Type Laser Source  600 , which is a part of FCIS based-LEMCS invented, is removed from FCIS based-LEMCS illustrated in  FIG. 2  and Pulsed Type Laser Source  500 , the averaged pulse energy PE av    840  of which is to be measured according to Eq. (16), is placed opposite Port_ 1   101  of FCIS  100  of FCIS based-LEMCS  111  as in  FIG. 1   
         [0194]    b-2) Pulsed Type Laser Source  500  lasing at wavelength λ (nm) given in  FIG. 1  is run and the Pulsed Gaussian Laser Beam  501  of Pulsed Type Laser Source  500  is oriented to Port_ 1   101  of FCIS  100  of FCIS based-LEMCS  111  as in  FIG. 1 . 
         [0195]    b-3) The output peak power levels P 0    400  of Pulsed Type Laser Source  500  are reduced to a few mW level in order to guarantee eye safety together with eye protection equipments by using one of the suitable one of the neutral density filters, the optical densities of which extends to 2.5, which are located in front of the collimators at z=0. 
         [0196]    b-4) By using an IR viewer card having a compatible spectral range with that of Pulsed Type Laser Source, the peak power levels P 0    400  of the Pulsed Gaussian Laser Beams  501  of Pulsed Type Laser Source  500  is reduced by a suitable neutral density filter, and the Pulsed Gaussian Laser Beams  501  are centered on Port_ 1  by means of Alignment Combination  162  in  FIG. 1 . The compatibilities and the relationships among the beam waists, the size of Port_ 1 , and the size of internal steel hemisphere, emphasized in “Details of FCIS” subsection of “DESCRIPTION” section, should be taken into account in this step. 
         [0197]    b-5) As soon as the Pulsed Gaussian Laser Beam  501  of Pulsed Type Laser Source  500  entering from Port_ 1   101  is fallen on the Internal steel hemisphere  110 , the inner diameter of which is 13 mm shown as in  FIG. 4 , the Second Photodiode  129  assembled with the internal steel hemisphere  110  on Port_ 3   103  starts detecting the optical flux entering from Port_ 1   101 . 
         [0198]    b-6) The maximization of the voltage output of Current to Voltage Converter  127  combined to the Second Photodiode  129  assembled with the internal steel hemisphere  110  on Port_ 3  which starts to detect the Pulsed Gaussian Laser Beam  501  entering from Port_ 1   101  is performed by means of Alignment Combination  162  and by tracking the screen of the Oscilloscope  130  in real time. With this process in the invention, the measurement reproducibility for individual and independent pulse energy measurements is enhanced because the crest corresponding to the maximum irradiance level (crest) of Pulsed Gaussian Laser Beam  501  entering from Port_ 1   101  is targeted on the same point defined by the Pin Hole  109  having a diameter of 0.1 mm, back of which 62.5 μm diameter core of Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  is rest/located. The amplitude of the maximization voltage on the screen of the Oscilloscope  130  is not important. What is important at this point is to obtain maximum voltage and maximum voltage is obtained when the crest of the maximum irradiance level of the Pulsed Gaussian Laser Beam  501  of Pulsed Type Laser Source  500  entering from Port_ 1   101  collides on the center of the Pin Hole  109  having a diameter of 0.1 mm, back of which 62.5 μm diameter core of Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  is rest/located. 
         [0199]    b-7) After completion of the maximization process, the output pulse power P 0    400  of Pulsed Type Laser Source  500  is adjusted to its normal operation power level to be measured and the Second Photodiode  129  assembled with internal steel hemisphere  110  on Port_ 3   103  of FCIS  100  of FCIS based-LEMCS  111  starts to be directly used for time/frequency related measurements, which are the averaged repetition frequency f av  (Hz)  331 , the averaged repetition period T av (s)  330 , the averaged pulse width PW av  (s)  342 , the averaged dead time DT av (s)  340 , and the averaged Duty Cycle av    299  which is normalized to 1. 
         [0200]    b-8) The pulsed voltage signal at the output of Current to Voltage Converter  127  connecting to the Second Photodiode  129  through Mechanical Attenuator  170  on Port_ 3   103 , caused by Pulsed Type Laser Source  500  operating in its normal operation power level, is observed on the screen of the Oscilloscope  130 . 
         [0201]    b-9) The time/frequency related parameters of the Pulsed Gaussian Laser Beams  501  of Pulsed Type Laser Source  500 , the averaged pulse energy PE av    840  in Eq. (16) of which is aimed to be measured, are directly measured and averaged in real time without the effect of time constant τ of FCIS  100  of FCIS based-LEMCS  111  and the effect of of the pulse response of the First Photodiode  120  by Time Interval Counter  135  in  FIG. 1 , which is traceable to  133 Cs (or  87 Rb) Atomic Frequency Standard in  FIG. 7 , to which Current to Voltage Converter  127  and the Second Photodiode  129 , are consecutively connected in this invention. The averaged repetition period T av (s)  330 , and the averaged repetition frequency f av  (Hz)  331  obtained from this measurement are the same parameters as those in Eq. (16). 
         [0202]    b-10) During the measurement of the averaged repetition frequency f av  (Hz)  331  and the averaged repetition period T av (S)  330  of Pulsed Type Laser Source  500 , the First Photodiode  120  measures the average photocurrent I av (A)  300  in  FIG. 1  and  FIG. 3 , proportional to the average optical power P av (W)  301  in  FIG. 3 , simultaneously as an advantage of this invention. 
         [0203]    b-11) The resultant and averaged pulse energy PE av (f av )  840  in Eq. (16), as a function of the averaged repetition frequency f av    331 , is calculated with the data series, I av (A)  300  obtained from “b-11”, the repetition period T av (s)  330  obtained from “b-10”, by considering =1/(2πR eq C eq )=995222 Hz from the equivalent circuit  171  of the First Photodiode  120  in  FIG. 3 and 320  obtained from the section of “a-) Determination of the spectral responsivity of FCIS based-LEMCS”. 
         [0204]    b-12) The maximum PW, ≦1.9×10 −4  s corresponding to =100 mJ pulse energy for a maximum peak power=522 W, which matches the peak power level P 0   400  of Pulsed Type Laser Source  500  in  FIG. 2  which can be detected by the First Photodiode  120  without saturation. 
         [0205]    The ultimate limit parameters of Pulsed Type Laser Source  500  to be measured by FCIS based-LEMCS  111  for the maximum peak laser power of =522 W in the invention are, 
         [0206]    minimum pulse width, ≅0.736 μs, corresponding to PE av    840  of 384 μJ obtained from the pulse response characteristic of the First Photodiode  120 , and 
         [0207]    minimum dead time, ≅1.7 μs from the necessary time of sufficient heat dissipation inside the internal steel hemisphere  110  as a target, which produces the minimum averaged repetition period of of 2.436 μs, corresponding to a maximum averaged repetition frequency of 410509 Hz. 
         [0208]    In the measurement of the averaged pulse energy of Pulsed Type Laser Source  500  lasing properly to the infinite pulse wave train given in  FIG. 3  by means of FCIS based-LEMCS  111 , the compatibility of the beam sizes with Port_ 1   101  and Port_ 3   103  of FCIS  100  of FCIS based-LEMCS  111 , and the permissible maximum energy level to be applied to FCIS based-LEMCS  111  should be taken into account and the calculations and approaches given in this invention should be regarded. Pulse energies of Pulsed Type Laser Source  500  operating in burst mode can be measured by FCIS based-LEMCS  111  by applying the suitable integrating/averaging time settings of Electrometer  119  in  FIG. 1 . 
         [0209]    In this section a brief uncertainty evaluation for FCIS based-LEMCS in this invention are introduced. This uncertainty analysis covers a pulse energy PE av    840  of 40 μJ and pulse energy PE av    840  of 100 mJ for a Pulsed Type Laser Source  500  lasing at 1549.0 nm (f av =500 Hz, Duty Cyde=0.5) and 1064.0 nm (f av 5 Hz, Duty Cycle=0.83) respectively. For both averaged repetition frequencies  331  are very very smaller than =995222 Hz and the frequency response term of Eq. (16), yields 1, so this term is not included in the uncertainty model function. The partial uncertainties of the uncertainty budgets given in  FIG. 9 a    and  FIG. 9 b    are u(I av )  351 , u(f av )  352 , u(R FCIS )  353 . These partial uncertainties includes the standard (combined) uncertainties coming from the traceable calibrations of Electrometer  119 , Time Interval Counter  135  to primary level standards shown in  FIG. 7 , and the spectral responsivity determination  320  of FCIS  100  of FCIS based-LEMCS  111  against Optical Power Transfer Standard  809  shown in  FIG. 7  and  FIG. 8 . The inclusion of these standard uncertainties coining from the individual calibration of Electrometer  119 , Time Interval Counter  135 , and  320  in the individual and relevant partial uncertainty value, designated as u(I av )  351 , u(f av )  352 , u(R FCIS )  353 , is executed as root of summing of the squared values of the standards uncertainties. The largest uncertainty portion in both u(I av )  351 , and u(f av )  352  is composed of the standard deviations during the measurement of the average photocurrent I av    300  generated by the First Photodiode  120  in Eq. (16), and the measurement of the averaged repetition frequency f av  (Hz)  331  (or repetition period T av  (s)  330 ), which have normal type distribution functions (multiplier=1). Because u(R FCIS )  353  is a predefined value obtained from the determination of described in the section of “a-) Determination of the spectral responsivity of FCIS based-LEMCS”, it is included in both of the uncertainty budgets as rectangular type distribution function (multiplier=). Regarding u(σ repro )  354 , which is named as the partial uncertainty in the error σ repro    329  in the measurement reproducibility of the averaged pulse energy of the pulsed type laser source; the error σ repro    329  in the measurement reproducibility is zero for perfect reproducibility in the uncertainty calculation. The partial uncertainty u(σ repro )  354  in the error σ repro    329  of the measurement reproducibility of the averaged pulse energy PE av    840  is calculated by using the standard deviations of the averaged pulse energy PE av    840  values obtained from the successive positioning processes of FCIS  100  of FCIS based-LEMCS  111  opposed to the collimator of the Pulsed Type Laser Source at z=0. 
         [0210]    c-) Calibration of a Commercial Laser Energy Meter by using Chopped Type Laser Source in FCIS based-LEMS; 
         [0211]    In the numbering showing the steps to be applied, “c” shows that this measurement series belongs to the section of “c-) Calibration of a Commercial Laser Energy Meter by using Chopped Type Laser Source in FCIS based-LEMS” and numbers as 1, 2, and etc. shows the sequence number steps being applied. Superscript “_clem” shows the relevant parameter in the calibration of Commercial Laser Energy Meter  999 . 
         [0212]    c-1) The complete setup demonstrated in  FIG. 2 , called as FCIS based-LEMCS  111 , is configured for traceable calibration of Commercial Laser Energy Meter  999  by using Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600 , which are generated by means of the combination of DC Motor  599  with a series chopper  901 - 909  from CW Gaussian Laser Beam  799  of CW Laser Source  800 , called four DFB lasers. 
         [0213]    c-2) Depending on the measurement range of Commercial Laser Energy Meter  999 , the selections of the relevant chopper having a individual Duty Cycle  322 , repetition frequency f (Hz)  322 , and the peak power P 0    400  of Chopped Type Laser Source  600  according to the Eq. (16). 
         [0214]    c-3) CW Laser Source  800  lasing at wavelength λ (nm) given in  FIG. 2  is run and the CW Gaussian Laser Beam  799  of CW Laser Source  800  is oriented to Port_ 1   101  of FCIS  100  of FCIS based-LEMCS  111  when DC Motor  599  is not activated and so the chopper  901 - 909  doesn&#39;t rotate. 
         [0215]    c-4) The output powers of CW Gaussian Laser Beam  799  of CW Laser Sources  800  in  FIG. 2  is reduced to a few mW level in order to guarantee eye safety together with eye protection equipments by using one of the suitable one of the neutral density filters, the optical densities of which extends to 2.5, which are located in front of the collimators of Single Mode Optical Fiber Patch Cord  876  at z=0. 
         [0216]    c-5) By using an IR viewer card having a compatible spectral range with that of CW Laser Source  800 , the CW Gaussian Laser Beam  799  still at the output of the chopper  901 - 909  in continuous regime, the power of which is reduced by means of a suitable neutral density filter, is centered on Port_ 1   101  of FCIS  100  of FCIS based-LEMCS  111  by means of Alignment Combination  162  in  FIG. 2  The compatibilities and the relationships among the beam waists, the size of Port_ 1   101 , and the size of internal steel hemisphere  110 , emphasized in “Details of FCIS” subsection of “Description” section, is taken into account in this step. 
         [0217]    c-6) As soon as the CW Gaussian Laser Beam  799  entering from the center point of Port_ 1   101  of FCIS  100  of FCIS based-LEMCS  111  is fallen on the internal steel hemisphere  110 , the circular diameter of which is 13 mm shown as in  FIG. 4 , the Second Photodiode  129  assembled with the internal steel hemisphere  110  on Port_ 3   103  of FCIS  100  of FCIS based-LEMCS  111  starts detecting the optical flux entering from Port_ 1   101 . At this step, DC Motor  599  is not activated and the chopper  901 - 909  doesn&#39;t rotate yet. 
         [0218]    c-7) When the chopper  901 - 909  doesn&#39;t rotate yet, and the maximization of the voltage output of Current to Voltage Converter  127  combined to the Second Photodiode  129  assembled with the internal steel hemisphere  110  on Port_ 3   103  of FCIS  100  of FCIS based-LEMCS  111  starting to detect the CW Gaussian Laser Beam  799  entering from Port_ 1   101  of FCIS  100  of FCIS based-LEMCS  111  is performed by means Alignment Combination  162  and by tracking the screen of the Oscilloscope  130  in real time. With this process in the invention, the measurement reproducibility for individual and independent pulse energy measurement is enhanced because the crest of CW Gaussian Laser Beam  799  corresponding to the maximum irradiance level entering from Port_ 1   101  is targeted on the same point defined by the Pin Hole  110  of 0.1 mm, back of which 62.5 μm diameter core of Zr ferrule  140  of HMS connector  132  of the First MM Optical Fiber Patch Cord  150  is rest/located. The amplitude of the maximization voltage on the screen of the Oscilloscope  130  is not important. What is important at this point is to obtain maximum voltage and maximum voltage is obtained when the crest of the maximum irradiance level of the CW Gaussian Laser Beam  799  entering from Port_ 1   101  collides on the center of Pin Hole  109  of 0.1 mm, detailed in  FIG. 5 . 
         [0219]    c-8) After completion of the maximization process, DC Motor  599  in  FIG. 2  is activated and the chopper  901 - 909  begins to rotate, and Chopped Type Laser Source  600  of FCIS based-LEMCM  111  and Chopped Gaussian Laser Beams  601  are available now. With beginning the rotation of the chopper  901 - 909 , the Second Photodiode  129  assembled with internal steel hemisphere  110  on Port_ 3   103  of FCIS based-LEMCS  111  starts to be directly used for time/frequency related measurements, the averaged repetition frequency (Hz)  843 , the averaged repetition period (s)  844 , and the Duty Cycle, normalized to 1. The combination of CW Laser Source  800  with the chopper  901 - 909  in the invention provides the nine different Duty Cycles varying from 0.17 to 0.83 at any repetition frequency f (Hz)  321  extending from 5 Hz to 2 kHz in the calibration processes of Commercial Laser Energy Meters  999  by means of FCIS based-LEMCS  111 , traceable to primary level standards given in  FIG. 7 . 
         [0220]    c-9) The voltage signal generated by the Second Photodiode  129  assembled with the internal steel hemisphere  110  on Port_ 3   103  of FCIS  100  of FCIS based-LEMCS  111  is chopped instead of CW Gaussian. Laser Beam  799  and Chopped Gaussian Laser Beams  601  generated by Chopped Type Laser Source  600  of FCIS based-LEMCM  111  are observed on the screen of the Oscilloscope  130 . 
         [0221]    c-10) The time/frequency related parameters of Chopped Gaussian Laser Beams  601  of Chopped Type Laser Source  600 , the reference and averaged pulse energy  845  of which is aimed to be measured, are directly measured and averaged, in real time, without the effect of time constant τ of FCIS  100  of FCIS based-LEMCS  111  and the effect of the pulse response of the First Photodiode  120  by Time Interval Counter  135  in  FIG. 2 , which is traceably calibrated to  133 Cs (or  87 Rb) Atomic Frequency Standard  804  in  FIG. 7 , to which Current to Voltage Converter and the Second Photodiode  129  is consecutively connected in the invention. The repetition period (s)  844 , and the repetition frequency (Hz)  843  obtained from this measurement are the same parameters as those in Eq. (16). 
         [0222]    c-11) During the measurement of the averaged repetition frequency (Hz)  843  and the averaged repetition period (s)  844  of the chopped Gaussian laser beams, the First Photodiode  120  measures the average photocurrent (A)  842  in  FIG. 2 , proportional to the average and reference pulse energy  845  in  FIG. 2 . The pulse energy is called as “the reference” because it will be measured by FCIS based-LEMCS  111  and then the same pulse energy level  845  will be applied to Commercial Laser Energy Meter  999  by substitution. 
         [0223]    c-12) The resultant and the averaged and reference pulse energy ( )  845  in Eq. (28), as a function of the averaged repetition frequency (Hz)  843 , is calculated with the data series, (A)  842  obtained from “c-11”, the averaged repetition period (s) obtained from “c-10”, by considering=1/(2πR eq C eq )=995222 Hz from the equivalent circuit  171  of the First Photodiode  120  in  FIG. 3 and 320  obtained from the section of “a-) Determination of the spectral responsivity of FCIS based-LEMCS”. 
         [0224]               (28) 
         [0225]    Eq. (28), which is written for Chopped Type Laser Source  600 , is the same as Eq. (16), which is written for the calculation of the averaged pulse energy of Pulsed Type Laser Source. The calculated pulse energy (f av )  845  by means of FCIS based-LEMCS  111  in unit of (J) will be the reference pulse energy  845  for Commercial Laser Energy Meters  999  to be calibrated, which is determined fully traceably to primary level standards demonstrated in  FIG. 7 . 
         [0226]    c-13) The sensitive surface of Commercial Laser Energy Meter  999  shown as in  FIG. 2 , which is Input Port  839 , is directly and perpendicularly placed against the propagation way of the Chopped Gaussian Laser Beam  601 , the averaged and reference pulse energy  845  of which is determined from the steps specified from “c-1” to “c-12”, which is called the reference averaged pulse energy. The readout of Commercial Laser Energy Meter  999  is recorded as PE clem    841  in unit of J. 
         [0227]    c-14) The linear calibration factor is calculated as,           which is traceable to primary standards, in units of W, A, and s.  945  is the linear calibration factor for Commercial Laser Energy Meter  999 . 
         [0228]    FCIS based-LEMCS  111  together with the calculations, the determination of spectral responsivity method, the calibration method of Commercial Laser Energy Meter  999  and the averaged pulse energy measurement method, all of which are given in the Section 3 and traceable to primary level standards shown in  FIG. 7  herein, is one embodiment,