Abstract:
A laser diode array assembly includes a laser diode array and a memory device integrally packaged with the array. The memory device includes operational information concerning the array. The memory device is accessible by a host external operating system which determines the manner in which the array is to be powered based on the operational information. The memory device may have the capability to be written to such that tie external operating system can record in the memory device significant events such as extreme operational conditions, operational faults, and the on-time or shot-count of the array. The assembly may include sensors to which the operating system is coupled. The assembly may further include a processing means to monitor the sensors and provide real-time updates to the external operating system such that laser diode array is continuously powered in an optimal manner.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 09/691,768, filed Oct. 18, 2000, U.S. Pat. No. 6,272,164, now allowed, which is a continuation of U.S. application Ser. No. 09/049,579, filed Mar. 27, 1998, and issued as U.S. Pat. No. 6,144,684 on Nov. 7, 2000, which is a continuation of application Ser. No. 08/692,600, filed Aug. 6, 1996, and issued as U.S. Pat. No. 5,734,672 on Mar. 31, 1998. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to lasers diodes and, in particular, to an assembly that includes a laser diode array, an integral memory device storing operational information about the laser diode array, and an integral processing device that records information to and retrieves information from the memory device. 
     BACKGROUND OF THE INVENTION 
     Semiconductor laser diodes have numerous advantages. They are small in that the widths of their active regions are typically submicron to a few microns and their heights are usually no more than a fraction of a millimeter. The length of their active regions is typically less than about a millimeter. The internal reflective surfaces, which are required in order to produce emission in one direction, are formed by cleaving the substrate from which the laser diodes are produced and, thus, have high mechanical stability. Additionally, high efficiencies are possible with semiconductor laser diodes with pulsed junction laser diodes having external quantum efficiencies near 50% in some cases. 
     The cost and packaging of laser diodes are problems that has limited their commercialization. It is only recently that both the technology and availability of laser diode bars, and a method for packaging them, has made two dimensional laser diode pump arrays a commercial reality. One technique for producing such a two dimensional laser diode array is demonstrated in the U.S. Pat. Nos. 5,040,187 and 5,128,951 to Karpinski. Also, newer techniques have been used to make more efficient an older packaging approach whereby individual diodes are sandwiched between two metallic foils. The advent of lower cost laser diodes and efficient packaging has led to the possibility of producing very large, solid-state laser systems which use many pump arrays. 
     While laser diode pump arrays have a relatively long life when compared to the traditional flash-lamp or arc-lamp pump sources, they are still considered consumable items that require periodic replacement. In some cases with modularized laser diode arrays, one may even wish to replace only a portion of the array. For pulsed lasers, the number of shots which the laser diode arrays have fired is recorded. For continuous-wave (CW) lasers, the amount of time the laser diode arrays have operated (time-on) is of interest. Typically, these values are monitored and stored within the external electronic control systems which operate these laser systems. These electronic control systems must contain a shot-counter or time-on counter for each laser diode pump array to determine the relative age of each laser diode array thereby permitting the development of a replacement schedule for each laser diode array. However, when a laser diode pump array is replaced, these shot-counters or on-timers must have the ability to be reset to zero if a new laser diode array is used. If a used laser diode array is installed, then these shot-counters or on-tirers must have the ability to be reset to a predetermined value. Furthermore, when a laser diode array is removed from a system for replacement, a difficulty arises in that there is no longer a shot count or on-time associated with the pump array, unless written records are meticulously kept. 
     In addition to the shot-count, there is other information about a diode array that is of particular interest, such as the serial number of the array, the number and frequency of over-temperature fault conditions, and the voltage drop (i.e. the resistance rise) across the array. These characteristics are useful for selecting an application for a used laser diode array, or for determining the causes of its failure. These characteristics are also important for warranty purposes. However, the operator of the system has no interest in recording these data since it may limit his or her ability to rely on the warranty when a failure arises. On the other hand, the manufacturer has a keen interest in knowing the operational history of an array for warranty purposes. 
     When semiconductor laser diodes are used as the optical pumping source for larger, solid-state laser systems, the emitted wavelength is critical. Laser diode pump arrays achieve efficient pumping of the laser host material (e.g. Neodymium-doped, Yttrium-Aluminum Garnet) by emitting all of their light energy in a very narrow spectral band which is matched to the absorption spectrum of the gain media (i.e. slabs, rods, crystals etc.), typically within 2-6 nanometers full-width at the half-maximum point (fwhm). The laser diode pump array emission wavelength is a function of the temperature at which the pump array is operated. The pump array temperature is a complicated function of many interrelated variables. The most important of these variables are the temperature of the coolant flowing to the diode array, the operational parameters of the diode array, and the configuration of the heat exchanger on which the laser diodes are mounted. The operational parameter of a CW driven array is simply the drive current. But for pulsed laser systems, the peak drive current, the repetition rate, and the pulse width of the drive current are all important operational parameters. Because the performance of the laser diode array changes during the service life of a laser diode array, the host external system controller has to compensate for any degradation of performance (output power or wavelength) by modifying these input operational parameters except for the heat exchanger configuration. Often, the altering of the operational parameters requires manual calibration of the arrays using external optical sensors. This is a tedious job and requires a skilled technician who understands the ramifications of modifying the interrelated variables which change the output power and wavelength. Even when the laser diode array&#39;s operational parameters are properly calibrated, rapid changes in the performance of the laser diode array may go unnoticed until the next scheduled maintenance. This manual calibration also is often required during the initial installation of the laser diode array assembly. 
     Therefore, a need exists for a laser diode array assembly that includes an integral means for recording operational events and maintaining this information with the assembly throughout its service life. It would also be beneficial for this laser diode array assembly to have the capability of instructing the external laser operating system on the input drive parameters that should be used to provide for optimal output of the laser diode array assembly. 
     SUMMARY OF THE INVENTION 
     A modular laser diode array assembly includes at least one laser diode array, an intermediate structure on which the array is mounted, and an integral memory device. The laser diode array has a plurality of laser diodes which are in electrical contact with at least one other of the plurality of laser diodes. The assembly further includes means for supplying external power to the laser diode array. The memory device stores operating information for the laser diode array and is mounted on the intermediate structure which may be a printed circuit board. The memory device communicates with an external operating system. After the assembly is installed in and connected to the external operating system, a system controller accesses the memory device to obtain the operating information (temperature, input power parameters, etc.) which enables the system controller to properly apply power to, or set conditions for, the laser diode array. 
     In another embodiment, the assembly includes sensors for sensing the operating conditions experienced by the laser diode array. The external operating system monitors the sensors to assist in determining the operational parameters at which the system is to be operated. These sensors may be optical power sensors, optical wavelength sensors, electrical input power sensors, temperature sensors, vibration sensors, etc. 
     In yet another embodiment, the assembly includes processing means that communicates with the external operating system. The processing means is coupled to the sensors for directly monitoring the operating conditions of the laser diode array and is also coupled to the memory device. Based on the operating conditions monitored, the processing means instructs the external operating system to supply the optimum operating parameters. Thus, the assembly is self-calibrating in that it monitors the operating conditions and instructs the external operating system to provide input power in a manner that allows for the optimum output. 
     Using the integral memory device and the processing means provides numerous benefits. For example, the shot-count or on-time value becomes physically a part of the assembly as it is stored within the integral memory device. This integral memory device could then be read from and updated, as necessary, by the control electronics of the external operating system or the processing means when one is used. 
     There are many additional pieces of data which could be stored in this memory device, such as: the array serial number; the number and times of fault conditions such as over temperature or activation of protection circuitry; the voltage drop across the array and the time of the occurrence if it changes significantly (this may be an indication of individual laser bar failures); and the array&#39;s spectral and power response to different operational conditions. The memory device may also record the ambient environmental conditions such as the ambient temperature, the ambient shock environment, ambient humidity, or electrostatic discharge (ESD) events resulting from the environment around the array. 
     The above summary of the present invention is not intended to represent each embodiment, or every aspect, of the present invention. This is the purpose of the figures and the detailed description which follow. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which: 
     FIG. 1A is a perspective view of a laser diode array used in the present invention; 
     FIG. 1B is a perspective view of another laser diode array used in the present invention; 
     FIGS. 2A-2D are views of a multiple-array assembly having an integral memory device and a sensor; 
     FIGS. 3A-3C are views of a multiple-array assembly having an integral processing device including a memory device, a sensor, and multiple photodetectors; 
     FIGS. 4A-4B are views of a single-array assembly having an integral processing device including a memory device, a sensor, and a photodetector; 
     FIG. 5 is a plan view of a single-array assembly having an integral memory device, a temperature sensor, and a photodetector; 
     FIG. 6 is a plan view of a multiple-array assembly having an integral processing device including a memory device, a temperature sensor, multiple photodetectors, and an input power sensing device; 
     FIG. 7 is perspective view of the multiple-array assembly of FIGS. 3A-3C including a connector and being installed on a heat exchanger; 
     FIG. 8 is a perspective view of a multiple-array assembly having an printed circuit board positioned at approximately 90 degrees from the plane in which the emitting surfaces reside; 
     FIG. 9 is a schematic view of a multiple-array assembly incorporating the present invention and being installed in an external operating system; and 
     FIG. 10 is a schematic view of an external operating system being coupled to multiple assemblies labeled  1 -N. 
    
    
     While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed. Quite to the contrary, the intent is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring initially to FIG. 1A, a laser diode array  10  is illustrated in a perspective view. The laser diode array  10  includes a plurality of laser diodes packages  12  each of which includes a laser diode  13  sandwiched between a heat sink  14  and a lid  17 . The laser diode packages  12  are arranged in a parallel fashion commonly referred to as a stack. At the ends of the stack are endcaps  18  and  19  through which power is supplied to the stack of laser diode packages  12 . A thermal backplane  20 , usually made of an electrically insulative material, such as beryllium oxide, is the surface to which each of the packages  12  is mounted. The laser diode array  10  is one type of array that can be used in the present invention. 
     In FIG. 1B, a second type of laser diode array  30  is illustrated. The laser diode array  30  includes a substrate  32  made of an electrically insulative material and a plurality of grooves  34  which are cut in the substrate  32 . Within each groove  34  is a laser diode bar  36 . To conduct electricity through the plurality of laser diode bars  36 , a metallized layer is placed within each groove  34  and connects adjacent grooves  34 . The bottom of the substrate  32  is the backplane through which heat flows to the heat exchanger positioned below the bottom. Although the number of grooves  34  is shown as ten, the application of the array  30  dictates the amount laser diode bars  36  and, therefore, the number of grooves  34 . Laser diode array  30  is another type of laser diode array that can be used with the present invention. 
     FIGS. 2A-2D are views of an assembly  40  having six laser diode arrays  30 , an integral memory device  42 , and a sensor  44 . The memory device  42  and the sensor  44  are mounted on a printed circuit board (PCB)  46 . The information on the memory device  42  can be accessed and the sensor  44  can be monitored through contact pads  47  located on the PCB  46 . A board heat sink  48  is disposed on the back of the PCB  46  and is the surface to which the backplanes of the laser diode arrays  30  are attached. The diode arrays  30  can be soldered to this heat sink  48  or fastened in other ways which minimize the thermal resistance across the interface of the heat sink  48  and the laser diode array  30 . 
     The sensor  44  can be of a type that measures output power or output wavelength (assuming it receives the emitted light). More commonly, the sensor  44  is a temperature sensor since the temperature of the arrays  30  is critical to their operation. If the sensor  44  is a temperature sensor, it could be moved to a location closer to the backplanes of the arrays  30 . The sensor  44  may also be an ESD sensor or one that measures the shot-count or on-time of the array  30 . Furthermore, the PCB  46  may contain multiple sensors although only one sensor  44  is shown. 
     The memory device  42  preferably is a non-volatile memory device such that the information stored therein is not altered when power is removed from the memory device  42 . An example of such a memory device  42  is the model 24632, manufactured by Microchip, of Chandler, Ariz. 
     To protect the emitting surfaces of the laser diode arrays  30 , a protective window  50  can be affixed to the assembly  40 . The protective window  50  is supported by a retainer frame  52 . The frame  52  and the window  50  may merely act to protect the upper emitting surfaces. Alternatively, the frame  52  and window  50  may completely seal the six laser diode arrays  30  by placing a sealing material between the frame  52  and the window  50 . The window  50  can be made of a variety of materials including acrylic with an anti-reflective coating. Besides the window  50  that is shown, the window  50  could be replaced by a diffractive, binary, or two-dimensional array of lenses to provide focusing and collimation to the beam of energy. FIG. 2D illustrates the assembly  40  without the window  50  and retainer frame  52 . 
     The laser diode arrays  30  require electrical energy to produce the emitted radiation. Thus, a pair of contact pads  54   a  and  54   b  are located on the PCB  46 . To provide electrical energy to the laser diode arrays  30 , a pair of leads  56   a  and  56   b  are disposed between the endcaps of the two end arrays  30  and the pads  54   a  and  54   b.  Adjacent arrays  30  are connected in electrical series through jumpers  57 . In the case where the window  50  and the frame  52  seal the laser diodes  30 , the leads  56   a  and  56   b  can be potted or bonded onto the window frame  52 . The host external operating system makes electrical contact with the assembly  40  through the contact pads  54   a  and  54   b.    
     The PCB  46  and the board heat sink  48  include holes  58  through which fasteners will pass to connect the assembly  40  to the ultimate heat sink which is typically a high efficiency heat exchanger. Also provided are indexing holes  60  which align the PCB  46  and, therefore, the array  30  on the ultimate heat sink. 
     Although the PCB  46  is shown as the intermediate structure between the array  30  and the memory device  42 , other structures could be used. For example, merely providing an epoxy layer which adheres the memory device  42  to the array  30  may suffice if the epoxy provides electrical insulation. 
     The memory device  42  contains the operating information for the laser diode arrays  30 . The types of information can range from the basic to the complex. For example, the identity of the laser diode array assembly  40  can be recorded in the memory device. This can include the wafer number of the wafers that were used to produce the laser diode bars that are contained in each array  30 . It may also include the lot number of the bars comprising the arrays  30  or the laser diode bar number. It may also include an inspector number associated with the individual who approved of the bar in the quality control department. 
     The memory device  42  can also be loaded with performance data on the laser diode array assembly  40 . For example, the center wavelength can be given as well as the wavelength shift as a function of temperature (i.e. Gallium Arsenide laser diodes shift at about 1 nanometer per about 3-4° C.). The wavelength distribution of the arrays  30  can be stored so as to provide the full-width at half maximum value (FWHM) (i.e. the difference between the wavelengths at the point on the wavelength distribution curve where the intensity is at one-half of its maximum value). This FWHM value is critical when the assembly  40  is used for solid-state laser pumping applications. The wavelength can also be given as a function of spatial orientation along the assembly  40 . 
     Information related to the output power can be included as well. For example, the output power can be given as a function of the efficiency of the arrays  30 , the current and voltage at which the arrays  30  are driven, or the threshold current (i.e. the current after which lasing occurs). The output power can also be given as a function of spatial orientation along the assembly  40 . Also, the estimated output power degradation of the array  30  over its service life can be stored. 
     The memory device  42  can also include extreme design values for various operating conditions that should not be exceeded for a particular array. For example, the maximum or minimum design operating temperature can be recorded as can the maximum design drive parameters such as current, pulse-width, duty-cycle, voltage, etc. This allows for a real-time comparison between the actual operating conditions and the extreme design conditions to ensure that no damage will occur to the laser diode array  30 . The external operating system may use such a comparison to shut-down the system when the extreme design values are exceeded. 
     Although the memory device  42  has been described thus far as having operational information that has been recorded before its delivery to the customer, the memory device  42  can also be updated with information throughout its service life. Typically, the external operating system is monitoring various environmental conditions including temperature, vibration, shock, humidity, and also the input drive parameters. Since the operating system is configured to read from the memory device  42 , the only difference needed to achieve the goal of updating the memory device  42  is merely having an external operating system with the capability to write to the memory device  42 . Consequently, the memory device  42  then captures the operational history of the array  30  which is advantageous for determining the cause of failures and for warranty purposes. 
     The types of operational information related to the service life of the array  30  that can be recorded in the memory device  42  is quite extensive. For example, the shot-count of a pulsed laser diode array  30  or the on-time of a CW laser diode array  30  can be recorded. This is a very important value when considering the warranty of the array  30 . 
     The extreme operating conditions which the laser diode array  30  experiences can be recorded in the memory device  42  which is also useful for warranty purposes and for determining the cause for failures. Thus, the maximum and minimum operating temperature can be recorded in the memory device  42 . Other operating conditions such as the maximum shock, vibration, and humidity can be recorded as well. The maximum drive parameters (current, voltage, pulse width, frequency, etc.) can also be recorded in the memory device  42 . Additionally, the extreme ambient conditions of the environment surrounding the array  30  or surrounding the entire external operating system can be stored as well (nonoperational or operational). 
     A list of incident reports may be recorded in the memory device  42 . This may include the over-temperature failures, over-current failures, over-voltage failures, reverse-voltage failures (i.e. wrong bias across the arrays  30 ), coolant-flow interrupts (to the heat exchanger), and electrostatic discharge events. These faults can be recorded as merely an affirmative response to whether the fault occurred or as the value of the condition. Additionally, a drop in the voltage across the array  30  is indicative of a single laser diode failure and may be recorded. For example, a typical voltage drop across one good laser diode is approximately 2.0 volts and about 0.5 volt after certain types of failures. The number of laser diode bar failures can be estimated by such a voltage drop. Other types of fault conditions may be included as well, including those fault conditions recorded by sensors monitoring the output of the arrays  30  (i.e. wavelength and power). 
     Thus far, only fault conditions, operating conditions, and non-operating conditions have been discussed as being data that are recorded in the memory device  42 . However, recording the dates and times of these conditions is also worthwhile and can be accomplished by having the external operating system write the times that these conditions occur in the memory device  42 . When the time values are recorded, the memory device  42  then can be used to store a variety of parameters as a function of time (temperature, input power, output power, output wavelength, etc. v. time). 
     FIGS. 3A-3C illustrate an assembly  140  having multiple arrays  30  similar to the assembly  40  of FIGS. 2A-2D. The assembly  140  includes a processor  143  and a temperature sensor  144  that are mounted on a PCB  146 . A heat sink  148  is located on the backside of the PCB  146  and is the structure to which the arrays  30  are attached. Each array  30  has a corresponding photodetector  149  which measures the output characteristics of the emitted light. As shown best in FIG. 3C, the emitted light reflects partially off the inside surface of the window  150  and then hits the photodetector  149 . The photodetector  149  may measure the power of the reflected light which corresponds to the output power of the entire array  30 . Alternatively, the photodetector  149  may be of a more advanced type that measures the output wavelength of the reflected beam which corresponds to the output wavelength of the emitted output. 
     The processor  143  as shown includes a memory portion which allows basic information to be stored therein (extreme operating temperatures, input powers, etc.) If a larger amount of information is to be stored, then it may be desirable to include a separate memory chip on the PCB  146 , like the memory device  42  in FIG. 2, and couple it to the processor  143  for storing the additional data. This may be required when the operational history of the laser diode array  30  is to be recorded. 
     The processor  143  is coupled to the temperature sensor  144  and to the photodetectors  149  through traces on the PCB  146 . The processor  143  is also coupled to an external operating system through contact pads  147 . In this way, the processor  143  determines the appropriate drive levels to be supplied by the external operating system based on the conditions it monitors through the temperature sensor  144  and the photodetectors  149 . The processor  143  also instructs the external operating system to supply the coolant at a temperature and a rate that maintains the temperature of the temperature sensor  144  at the desired value. The processor  143 , therefore, provides a self-calibrating system in that any deviations seen in the output power and wavelength can be altered by instructing the operating system to change the input drive parameters and the coolant characteristics. 
     The processor  143  would typically be an Application Specific Integrated Circuit (ASIC) or a hybrid, custom-manufactured model. 
     FIGS. 4A and 4B illustrate an assembly  180  having a single array  182 , a processor  184 , a photodetector  186 , and a temperature sensor  188 . The array  182  holds substantially more bars than arrays  10  and  30  of FIGS. 1A and 1B. The photodetector  186  and the temperature sensor  188  are mounted on a PCB  190  and are coupled to the processor  184  which is also mounted on the PCB  190 . The array  182  is mounted to a heat sink  189  below the PCB  190 . Power is supplied to the array  182  via a pair of contacts  192  and  194  which are coupled to the array  182  via leads  192   a  and  194   a.  A trace  194   b  runs within the PCB  190  from the lead  194   a  to the endcap of the array  182  adjacent the photodetector  186 . 
     The processor  184  has internal memory portion with enough capacity to perform the required tasks. Alternatively, a memory device can be mounted on the PCB  190  and coupled to the processor  184 . 
     Also connected to the processor  184  is a circuit  196  which limits high power being received by the processor  184 . This circuit  196  is coupled to the input power leads and allows the processor  184  to determine the voltage drop across the array  182  or the current therethrough. Because the array  182  is usually coupled in series with a field effect transistor (FET) and a known voltage drop occurs across the diode array  182  and the FET, the processor  184  could also monitor the voltage drop across the FET to determine the voltage drop across the array  182 . The change in the voltage drop across the array  182  is indicative of a failure of the individual laser diode bars within the array  182 . The circuit  196  may include a fuse for guarding against high voltage or high current. 
     The use of such a circuit  196  also permits the counting of each shot supplied to the array  182  or the amount of on-time if array  182  is a CW laser. Thus, the processor  184  would count and store these values. 
     Although the circuit  196  has been described as one which measures the voltage drop across the array  182  or counts shots, it could also include a reverse-bias sensor (possibly an electrical diode) that permits the flow of current in one direction. If a voltage is applied in the wrong direction, then the current will flow through the electrical diode instead of the array  182  which decreases the likelihood of any harm to the array. Thus, the processor  184  can monitor the occurrence of a reverse-bias fault. 
     The circuit  196  can also include components for monitoring a electrostatic discharge across the array  182 . Thus, the processor  184  could monitor this circuit  196  for such an event and record it as well. 
     FIG. 5 illustrates an assembly  200  having a single array  202 , a memory device  204 , a photodetector  206 , and a temperature sensor  208 . These memory device  204  and the photodetector  206  are mounted on a PCB  210  while the array is mounted on a heat sink on the bottom of the PCB  210 . Thus, this single-array assembly  200  does not have the processing capability of assembly  180  in FIG.  4 . Instead, assembly  200  supplies to the external operating system the operational information needed to operate the array  202 . Also, the memory device  204  can be configured to receive and record information (fault conditions, operating conditions, etc.) from the external operating system. 
     The external operating system communicates with the memory device  204  by the contact pads  212  at the edges of the PCB  210 . Likewise, the external operating system communicates with the photodetector  206  and the temperature sensor  208  via the pads  212 . 
     FIG. 5 also illustrates the geometrical configuration of the assembly  200 . The emitting surfaces of the laser diode array  202  are within an area defined by LDY multiplied by LDX. The area of the PCB  210  is defined PCBX multiplied by PCBY. It is desirable to keep the ratio of the PCB area to the emitting area as low as possible such that the assembly  200  having these additional components (e.g. sensors, memory devices, processors, etc.) is not much larger that just the array. This is important for retrofitting purposes. Generally, the ratio of the PCB area to the emitting area is less than approximately 10 to 1. In a preferred embodiment, the ratio is in the range from about 5 to 1 to about 7 to 1. When a connector is added to the PCB  210  (see FIGS. 7 and 9 below), the ratio is less than about 14 to 1. 
     FIG. 6 illustrates an assembly  230  having six arrays  30  which is very similar to the assembly  140  shown in FIGS  3 A- 3 C. However, the processor  232  is coupled to the contacts  233  and  234  through circuits  236  and  238 . These circuits  236  limit the high power to the processor  232  so as to allow the processor  232  to determine the voltage drop across the six arrays  30 . 
     Again, circuits  236  and  238  may instead, or in addition to what is described above, provide for electrostatic discharge sensing. 
     Circuits  236  and  238  may also be used for counting the shots of a pulsed laser or the on-time for a CW laser since the processor  232  can receive a signal from these circuit each time power is supplied to the assembly  230 . Alternatively, if circuits  236  include an electromagnetic sensor (e.g. a Hall&#39;s Effect sensor) then they just need to be in close proximity to the arrays  30  or the contact pads  233  and  234  such that each time a high-current pulse is supplied to the assembly  200 , the Hall&#39;s Effect sensor is tripped by the resultant electromagnetic field. The processor  232  then receives the signal after each shot. 
     The arrays  30  have a finite life which is in a large part a function of the temperature at which they are operated and the power is supplied thereto. Because the processor  232  monitors both the temperature and the input power, the processor  232  can compare these values to a range of standard, assumed, operating conditions. Then, the processor  232  modifies the estimated life at a predetermined rate programmed in the processor  232  based on the actual conditions under which the arrays  30  are being operated. In a preferred embodiment, not only would the processor  232  form the external operating system of the amount of service that is remaining, but the processor  232  would also inform the external operating system of the amount that the estimated life has been adjusted based on the actual operating conditions. 
     FIG. 7 illustrates an assembly  250 , similar to the one shown in FIGS. 2A-2D, that is mounted on a heat exchanger  252  having an inlet port  254  and an outlet port  256 . The assembly  250  further includes a connector  258  to which the external operating system is coupled. The arrays  30  are connected to the heat sink  257  of the PCB  259 . The heat sink  257  of the PCB  259  is mounted on the heat exchanger  252  by a series of fasteners  260 . 
     The connector  258  is coupled to a memory device  261 , to a sensor  262  (i.e. one of the types discussed thus far), and to power supply contact pads  264  and  266 . Each of these devices is mounted on the PCB  259  and is coupled to the connector  258  through traces located on the PCB  259 . The connector  258  provides for an easy connection between the assembly  250  and the external operating system. 
     FIG. 8 illustrates an alternative embodiment in which an assembly  290  includes a PCB  292  that is located in a plane that is generally perpendicular to the emitting surfaces of arrays  30 . Consequently, the arrays  30  are elevated slightly from a base  294  which attaches the assembly  290  to a heat exchanger. Again, the assembly  290  includes a memory device  296  and two sensors  297  and  298 . Typically, sensor  298  is a temperature sensor and sensor  297  is a photodetector. Each of the sensors  297  and  298  and the memory device  296  are coupled to contact pads  299  at the end of the PCB  292  through traces (not shown) in the PCB  292 . The assembly  290  communicates with the external operating system through these contact pads  299 . 
     FIG. 9 illustrates the assembly  250  of FIG. 7 installed in the external operating system. Thus, a system controller  300  is coupled to drive electronics  302  which supply the electrical power needed to operate the diode arrays  30 . The system controller  300  is also coupled to a chiller  304  which supplies the cooling fluid to the heat exchanger  252  (FIG.  7 ). The system controller  300  receives operational information from the memory device  261  via the connector  258 . For example, the operational information received from the memory device  261  may inform the controller  300  that to obtain X watts of output power at 808 nanometers, the temperature at the temperature sensor  262  must be 31° C. and the arrays must be driven at 110 amps with a rate of 30 Hz, and a pulse width of 220 microseconds. The system controller  300  then causes the drive electronics  302  to supply the requested input power and causes the chiller  304  to provide coolant at a rate and a temperature that will maintain sensor  262  at 31° C. 
     Although the cooling system has been described as a chiller  304 , the system could also be one which utilizes solid-state thermoelectric coolers such as those manufactured by Marlow Industries of Dallas, Tex. The cooling capacity of these devices varies as a function of the input power. Thus, the system controller  300  would control the electrical power to the thermoelectric coolers such that their cooling capacity would result in the desired temperature at the arrays  30 . 
     The controller  300  also may store in the memory device  261  operational conditions if the configuration of the memory device  241  allowing for this information. Thus, the controller  300  could record to the memory device  261  extreme operating conditions (temperature, humidity, shock, vibration, the amount of on-time or the number of shots, etc.), extreme non-operating conditions (temperature, humidity, shock, vibration), extreme input powers (current, voltage, duty cycle, etc.), and fault conditions (coolant non-flow condition, electrostatic discharge, over-temperature fault, over-power fault, reverse-bias faults). Clearly, sensors (vibration sensors, shock sensors, humidity sensors, etc.) which measure these types of operating conditions would need to be incorporated onto the PCB or be adjacent the assembly  250  and monitored by the controller  300 . 
     If a processor is used on the assembly  250 , then the processor may monitor these sensors instead of the controller  300  monitoring them. Additionally, a processor could monitor the output of the assembly  250  and provide real-time modifications to the instructions sent to the system controller  300 . Thus, the basic operating information stored in the memory device  261  would serve as a starting point for operation and be modified based on the conditions sensed by the sensors and monitored by the processor. 
     FIG. 10 is a schematic illustrating a concept similar to what is shown in FIG. 9 except that the external operating system  330  is coupled to multiple assemblies  332 ,  334 ,  336  to produce the desired output. For example, the desired output from each assembly may by X watts at 808 nanometers. The operating system  330  then receives information from each assembly  332 , 334 , and  336  through the data interface lines which indicates the temperature and input power require to produce this output. Each assembly  332 ,  334 , and  336  will usually require slightly different operating parameters (e.g. 33° C., 36° C., and 32° C.; or  105 A,  108 A, and  101 A) to achieve the desired output. Consequently, the operating system  330  supplies coolant and input power at different levels to each assembly  332 ,  334 , and  336 . The operating system  330  may monitor sensors on the assemblies  332 ,  334 ,  336  through the sensor lines. Alternatively, if a processor is present on each of the assemblies  332 ,  334 ,  336 , the processor may monitor the sensors and instruct the operating system  330  accordingly through the data interface lines. 
     The present invention is quite useful for numerous reasons. For example, one of the main factors affecting yield and, therefore, the cost of laser diode pump arrays, is selecting only laser diode bars within a small spectral range for incorporation into one array. There is a significant cost savings if it is possible to use pump arrays which have a larger range in their peak emission spectra, since the system control electronics will be able to compensate for the array&#39;s spectral differences by using the stored thermal and spectral (wavelength) information. Furthermore, storing the thermal/spectral data within the assembly considerably simplifies replacement of a used or damaged assembly by allowing for the automatic compensation for the new assembly by merely accessing this data within the assembly&#39;s memory device. There is no longer the need to build a replacement array that exactly matches the used or damaged array. 
     Because the shot count or timer is integral with the assembly, rather than with the external control system electronics, the records are accurately maintained. And, a simplified way of recording significant events (faults, extreme conditions, etc.) is provided. Consequently, the need for meticulously recording this type of information on paper is obviated and, therefore, the integrity of the operational information on the array is greatly improved. Accessing this information from the memory device of the assembly is also useful for later analyzing the problems experience by the assembly. 
     The safety features of the assembly are greatly improved by providing in-situ monitoring of such operating conditions such as the array&#39;s voltage, temperature, ambient humidity, and the occurrence of fault conditions. This information can be used to shut-down the assembly to avoid damage to the assembly or injury to the operator of the assembly. 
     Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the invention, which is set forth in the following claims.