Abstract:
The present invention discloses a method for detecting influence on a laser from back-reflected light of the laser and a detection device. The method includes: receiving laser light input by a laser; splitting the input light into first detection light and second detection light via a beam coupler having a specific distribution proportion, and outputting the first detection light and the second detection light to a first optical power meter and an adjustable reflector, respectively; receiving a part of the second detection light reflected by the adjustable reflector, splitting the part of the second detection light reflected by the adjustable reflector into first back-reflection light and second back-reflection light, and returning the first back-reflection light and the second back-reflection light to the laser and the first optical power meter, respectively, detecting power of the first detection light by using the first optical power meter, and detecting power of the second back-reflection light by using a second optical power meter, and calculating power of the input light of the laser and power of the first back-reflection light, and establishing a power corresponding relationship between the power of the first back-reflection light and the power of the input light of the laser. By means of the foregoing manner, the present invention can detect a corresponding relationship between power of back-reflection light and power of input light of a laser.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to the field of optical technologies, and more particularly to a method for detecting influence on a laser from back-reflection light of the laser and a detection device. 
       BACKGROUND 
       [0002]    A semiconductor laser is a laser in which a semiconductor material is used as a working substance, has advantages such as a small volume, high efficiency, a simple structure, a relatively long service life, simple modulation, and a relatively low price, and is widely applied in the industry, communication, military, life science, medical treatment. 
         [0003]    However, during working of the semiconductor laser, when a part of laser light emitted by the semiconductor laser returns back into the laser chip along the original path, laser power of the semiconductor laser decreases, which affects quality of a laser beam of the semiconductor laser, and burns the diode chip in severe cases, causing the laser to fail. With different chips and different packaging modes, back-reflection light of the semiconductor laser affects a laser beam differently. How to detect influence on a laser beam from back-reflection light is a problem that requires an urgent solution. 
       SUMMARY 
       [0004]    A technical problem that the present invention is mainly to resolve is to provide a method for detecting influence on a laser from back-reflection light of the laser and a detection device, which detects a corresponding relationship between power of back-reflection light and power of input light of a laser. 
         [0005]    To resolve the foregoing technical problem, a technical solution used by the present invention is to provide a method for detecting influence on a laser from back-reflection light of the laser, including: receiving input light input by a laser; splitting the input light into first detection light and second detection light, and outputting the first detection light and the second detection light to a first optical power meter and an adjustable reflector, respectively, where power of the first detection light and power of the input light satisfy a first predetermined relationship; receiving a part of the second detection light reflected by the adjustable reflector, splitting the part of the second detection light reflected by the adjustable reflector into first back-reflection light and second back-reflection light, and returning the first back-reflection light and the second back-reflection light to the laser and the first optical power meter, respectively, where power of the second back-reflection light and power of the first back-reflection light satisfy a second predetermined relationship; detecting the power of the first detection light by using the first optical power meter, and detecting the power of the second back-reflection light by using a second optical power meter; calculating the power of the input light of the laser according to the power of the first detection light, calculating the power of the first back-reflection light according to the power of the second back-reflection light, and establishing and outputting a power corresponding relationship between the power of the first back-reflection light and the power of the input light of the laser; and rotating the adjustable reflector times, to enable the adjustable reflector to be located at different reflection angles to reflect a part of the first detection light, so as to output power corresponding relationships, where is natural number greater than or equal to 2. 
         [0006]    The first predetermined relationship between the power of the first detection light and 
         [0007]    the power of the input light is: 
         [0000]        P′ output=½Pinput
 
         [0008]    where Error! Reference source not found. is the power of the first detection light, and Error! Reference source not found. is the power of the input light; and 
         [0009]    the second predetermined relationship between the power of the second back-reflection light and the power of the part of the first detection light reflected by the adjustable reflector is: 
         [0000]        P′   back−reflected   =P″   back−reflected =½ P   r eflected  
 
         [0010]    where Error! Reference source not found. is the power of the first back-reflection light, Error! Reference source not found, is the power of the second back-reflection light, and Error! Reference source not found, is the power of the part of the first detection light reflected by the adjustable reflector. 
         [0011]    The method further includes: determining that the power of the first back-reflection light is greater than or equal to a power threshold value, and if the power of the first back-reflection light is greater than or equal to the power threshold value, raising an alarm. 
         [0012]    The step of outputting the second detection light to an adjustable reflector is specifically: collimating the second detection light by using a collimating lens, and outputting the second detection collimated light to the adjustable reflector; and the step of receiving a part of the second detection light reflected by the adjustable reflector is specifically: receiving, by using the collimating lens, the part of the second detection light reflected by the adjustable reflector. 
         [0013]    The method includes: establishing a mathematical relationship between the power of the first back-reflection light and the power of the input light of the laser according to the Error! Reference source not found. power corresponding relationships and with reference to a preset mathematical model. 
         [0014]    To resolve the foregoing technical problem, a technical solution used by the present invention is to provide a detection device, including a dual-channel optical coupler, a first optical power meter, a second optical power meter, an adjustable reflector, and a processor, where a first left port, a second left port, a first right port, and a second right port are disposed on the dual-channel optical coupler, the first left port is connected to a laser, the first optical power meter is connected to the first right port, the adjustable reflector is located in front of the second right port, the second optical power meter is connected to the second left port, and the processor is connected to the first optical power meter, the second optical power meter, and the adjustable reflector, respectively; the dual-channel optical coupler is configured to: receive, by using the first left port, input light input by the laser, split the laser input light into first detection light and second detection light, output the first detection light to the first optical power meter by using the first right port, and output the second detection light to the adjustable reflector by using the second right port, where power of the first detection light and power of the laser input light satisfy a first predetermined relationship, the adjustable reflector reflects a part of the second detection light to the second right port; the dual-channel optical coupler is further configured to: receive, by using the second right port, a part of the second detection light reflected by the adjustable reflector, split the part of the second detection light reflected by the adjustable reflector into first back-reflection light and second back-reflection light, return the first back-reflection light to the laser by using the first left port, and send the second back-reflection light to the first optical power meter by using the second port, where power of the second back-reflection light and power of the part of the first detection light reflected by the adjustable reflector satisfy a second predetermined relationship; and detect the power of the first detection light by using the first optical power meter, and detect the power of the second back-reflection light by using the second optical power meter; the processor is configured to: calculate the power of the input light of the laser according to the power of the first detection light, calculate power of the first back-reflection light according to the power of the second back-reflection light, and establish and output a power corresponding relationship between the power of the first back-reflection light and the power of the output light of the laser; and the processor is further configured to control the adjustable reflector to rotate for N−1 times, to enable the adjustable reflector to be located at N different reflection angles to reflect a part of the first defection light, so as to output N power corresponding relationships, where N is natural number greater than or equal to 2. 
         [0015]    The first predetermined relationship between the power of the first detection light and the power of the laser input light is: 
         [0000]        P′ output=½Pinput
 
         [0016]    where Error! Reference source not found. is the power of the first detection light, and Error! Reference source not found. is the power of the laser input light; and 
         [0017]    the second predetermined relationship between the power of the second back-reflection light and the power of the part, of the first detection light reflected by the adjustable reflector is: 
         [0000]        P′   back−reflected =½ P   r eflected  
 
         [0018]    where Error! Reference source not found. is power of second light, and Error! Reference source not found. is the power of the part of the first detection light reflected by the adjustable reflector. 
         [0019]    The detection device further includes an alarm apparatus, and the alarm apparatus is connected to the processor; and the processor is further configured to: determine whether the power of the first back-reflection light is greater than or equal to a power threshold value, and if the power of the first back-reflection light is greater than or equal to the power threshold value, control the alarm apparatus to raise an alarm. 
         [0020]    The detection device further includes a collimating lens; and the collimating lens is disposed between the second left port and the adjustable reflector, the collimating lens is configured to collimate the second detection light and output the collimated second detection light to the adjustable reflector, and the part of the second detection light reflected by the adjustable reflector passes through the collimating lens and then be focused into the second left port. 
         [0021]    The processor is further configured to establish a mathematical relationship between the power of the first back-reflection light and the power of the input light of the laser according to the N power corresponding relationships and with reference to a preset mathematical model. 
         [0022]    Beneficial effects of the present invention are: Different from a case in the prior art, in the present invention, input light of a laser is split into first detection light and second detection light, the first detection light enters a first optical power meter, the second detection light enters an adjustable reflector, the adjustable reflector reflects a part of the first detection light, a part of the second detection light reflected by the adjustable reflector is split into first back-reflection light and second back-reflection light, the first back-reflection light is used as back-reflection light of the laser and returns to the laser, and the second back-reflection light enters the second optical power meter, where power of the first detection light and power of the input light satisfy a first predetermined relationship, and power of the second back-reflection light and power of the first back-reflection light satisfy a second predetermined relationship. Therefore, the power of the input light may be calculated by using the power of the first detection light, and the power of the first back-reflection light is calculated by using the power of the second back-reflection light, so as to establish a corresponding relationship between power of back-reflection light of the laser and the power of the input light of the laser. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a flow chart of an implementation manner of a method for detecting influence on a laser from back-reflection light of the laser according to the present invention; and 
           [0024]      FIG. 2  is a schematic diagram of an implementation manner of a detection device according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    The present invention is described below in detail with reference to the accompanying drawings and implementation manners. 
         [0026]    Referring to  FIG. 1 , a method for detecting influence on a laser from back-reflection light of the laser includes: 
         [0027]    Step S 201 : Receive input light input by a laser. 
         [0028]    In this embodiment, the laser refers to that a core pump source part in the laser does not include another optical device, for example, a laser chip. 
         [0029]    Step S 202 : Split the input light into first detection light and second detection light, and output the first detection light and the second detection light to a first optical power meter and an adjustable reflector, respectively, where power of the first detection light and power of the output light satisfy a first predetermined relationship. 
         [0030]    The laser input light is split into the first detection light and the second detection light according to a predetermined requirement. Therefore, in addition to that power of the first detection light and power of the input light satisfy a first predetermined relationship, power of the second detection light and the power of the input light also satisfy a particular relationship. In an implementation manner of the present invention, the input light of the laser is split into the first detection light and the second detection light by 5:5. That is, the input light of the laser is divided into two equal parts, and the power of the first detection light and the power of the second detection light are the same, and are both half of the input light of the laser, so that the first predetermined relationship is: 
         [0000]        P′ output=½Pinput
 
         [0031]    where Error! Reference source not found. is the power of the first detection light, and Error! Reference source not found. is the power of the laser input light. 
         [0032]    It should be noted that: a part of the second detection light reflected by the adjustable reflector is equivalent to back-reflection light of the laser, where the back-reflection light causes laser power of the laser to decrease, which affects quality of the input light of the laser. 
         [0033]    Step S 203 : Receive a part of the second detection light reflected by the adjustable reflector, split the part of the second detection light reflected by the adjustable reflector into first back-reflection light and second back-reflection light, and return the first back-reflection light and the second back-reflection light to the laser and the first optical power meter respectively, where power of the second back-reflection light and power of the first back-reflection light satisfy a second predetermined relationship. 
         [0034]    The part of the second detection light reflected by the adjustable reflector is also split into the first back-reflection light and the second back-reflection light according to a predetermined requirement. Therefore, in addition to that the power of the first back-reflection light and power of the part of the second detection light reflected by the adjustable reflector satisfy a particular relationship, the power of the second back-reflection light and the power of the part of the second detection light reflected by the adjustable reflector also satisfy a particular relationship, so as to derive the second predetermined relationship between the power of the first back-reflection light and the power of the second back-reflection light. In an implementation manner of the present invention, the part of the second detection light reflected by the adjustable reflector is divided into the first back-reflection light and the second back-reflection light by 5:5. That is, the part of the second detection light reflected by the adjustable reflector is divided into two equal parts, and the power of the first back-reflection light and the power of the second back-reflection light are the same, and are both half of the part of the second detection light reflected by the adjustable reflector, so that the second predetermined relationship is: 
         [0000]        P′   back−reflected   =P″   back−reflected =½ P   r eflected  
 
         [0035]    where Error! Reference source not found. is the power of the first back-reflection light, Error! Reference source not found. is the power of the second back-reflection light, and Error! Reference source not found. is the power of the part of the first detection light reflected by the adjustable reflector. 
         [0036]    Step S 204 : Detect the power of the first detection light by using the first optical power meter, and detect the power of the second back-reflection light by using a second optical power meter. 
         [0037]    The first optical power meter and a second optical power meter are both configured to detect power of light. 
         [0038]    Step S 205 : Calculate the power of the input light of the laser according to the power of the first detection light, calculate the power of the first back-reflection light according to the power of the second back-reflection light, and establish a power corresponding relationship between the power of the first back-reflection light and the power of the input light of the laser. 
         [0039]    To prevent working power of the laser from changing and prevent the power of the input light from being affected, during detection of influence on the laser from back-reflected light, the laser may keep working at fixed power to perform detection. Certainly, when the laser works at different power, influence on the input light of the laser from the back-reflection light of the laser may also be detected. 
         [0040]    Step S 206 : Rotate the adjustable reflector for N−1 times, to enable the adjustable reflector to be located at N different reflection angles to reflect a part of the first detection light, so as to output N power corresponding relationships, where N is natural number greater than or equal to 2. 
         [0041]    When the adjustable reflector is located at a different reflection angle, a different amount of the second detection light is reflected by the adjustable reflector, and it is simulated that the laser generates back-reflection light having different power. By using the N power corresponding relationships, influence on the power of the input light of the laser from power of back-reflection light may be observed intuitively. 
         [0042]    Further, the method further includes: 
         [0043]    Step S 207 : Establish a mathematical relationship between the power of the first back-reflection light and the power of the input light of the laser according to the N power corresponding relationships and with reference to a preset mathematical model. 
         [0044]    It should be noted that: the mathematical relationship mentioned in the present invention is not only limited to a linear relationship, and there may also be more than only one mathematical relationship, and may be multiple mathematical relationships. For example, when power of back-reflection light is within a different range, a different mathematical relationship is presented. 
         [0045]    When the power of the back-reflection light is excessively high, the back-reflection light may damage the chip of the laser. To reduce a risk of damaging the chip of the laser during detection of influence on the laser from the back-reflection light of the laser, the method further includes: 
         [0046]    Step S 208 : Determine whether the power of the first back-reflection light is greater than or equal to a power threshold value, and if the power of the first back-reflection light is greater than or equal to the power threshold value, the process enters Step S 209 , or otherwise, skip processing. 
         [0047]    The power threshold value is a preset maximum power value of back-reflected light that the laser can withstand 
         [0048]    Step S 209 : Raise an alarm. 
         [0049]    A manner of the alarm includes, but is not limited to, a sound alarm, and an image alarm. 
         [0050]    Because the second detection light presents a radiated form, to make it convenient for the adjustable reflector to reflect a part of the second detection light, before the second detection light is further output to the adjustable reflector, collimation may be performed by using a collimating lens. The step of outputting the second detection light to an adjustable reflector in Step S 202  is specifically: collimating the second detection light by using a collimating lens, and outputting the second detection collimated light to the adjustable reflector. The step of receiving a part of the second detection light reflected by the adjustable reflector in Step S 203  is specifically: receiving, by using the collimating lens, the part of the second detection light reflected by the adjustable reflector. 
         [0051]    In an implementation manner of the present invention, input light of a laser is split into first detection light and second detection light, the first detection light enters a first optical power meter, the second detection light enters an adjustable reflector, the adjustable reflector reflects a part of the first detection light, a part of the second detection light reflected by the adjustable reflector is split into first back-reflection light and second back-reflection light, the first back-reflection light is used as back-reflection light of the laser and returns to the laser, and the second back-reflection light enters the second optical power meter, where power of the first detection light and power of the input light satisfy a first predetermined relationship, and power of the second back-reflection light and power of the first back-reflection light satisfy a second predetermined relationship. Therefore, the power of the input light may be calculated by using the power of the first detection light, and the power of the first back-reflection light is calculated by using the power of the second back-reflection light, so as to establish a corresponding relationship between power of back-reflection light of the laser and the power of the input light of the laser. 
         [0052]    The present invention further provides an implementation manner of a detection device. Referring to  FIG. 2 , a detection device  30  includes a dual-channel optical coupler  301 , a first optical power meter  302 , a second optical power meter  303 , an adjustable reflector  304 , and a processor  305 . A first left port  3011 , a second left port  3012 , a first right port  3013 , and a second right port  3014  are disposed on the dual-channel optical coupler  301 . The first left port  3011  is connected to a laser  40 . The first right port  3013  is connected to the first optical power meter  302 . The adjustable reflector  304  is located in front of the second right port  3014 . The second left port  3012  is connected to the second optical power meter  303 . The processor  305  is connected to the first optical power meter  302 , the second optical power meter  303 , and the adjustable reflector  304 , respectively. 
         [0053]    The dual-channel optical coupler  301  is configured to receive, by using the first left port  3011 , laser light input by the laser  40 , split the input light into first detection light and second detection light, output the first detection light to the first optical power meter  302  by using the first right port  3013 , and output the second detection light to the adjustable reflector  304  by using the second right port  3014 , where the power of the first detection light and power of the output light satisfy a first predetermined relationship. 
         [0054]    The dual-channel optical coupler  301  splits the input light of the laser  40  into the first detection light and the second detection light according to a predetermined relationship. In an implementation manner of the present invention, the input light of the laser  40  is split into the first detection light and the second detection light by 5:5. That is, the input light of the laser  40  is divided into two equal parts, the power of the first detection light and power of the second detection light are the same, and are both half of the input light of the laser  40 , so that the first predetermined relationship is: 
         [0000]        P′ output=½Pinput
 
         [0055]    where Error! Reference source not found. is the power of the first defection light, and Error! Reference source not found. is the power of the input light. 
         [0056]    The adjustable reflector  304  reflects a part of the second detection light to the second right port  3014 . The part of the second detection light reflected by the adjustable reflector  304  enters the dual-channel optical coupler  301  by using the second right port  3014 . The dual-channel optical coupler  301  is further configured to receive, by using the second right port  3014 , the part of the second detection light reflected by the adjustable reflector  304 , split the part of the second detection light reflected by the adjustable reflector  304  into first back-reflection light and second back-reflection light, return the first back-reflection light to the laser  40  by using the first left port  3011 , and send the second back-reflection light to the first optical power meter  302  by using the second port, where power of the second back-reflection light and power of the first back-reflection light satisfy a second predetermined relationship. 
         [0057]    The dual-channel optical coupler  301  also splits the part of the second detection light reflected by the adjustable reflector  304  into the first back-reflection light and the second back-reflection light according to a predetermined requirement. Therefore, in addition to that the power of the first back-reflection light and the power of the part of the second detection light reflected by the adjustable reflector  304  satisfy a particular relationship, and the power of the second back-reflection light and the power of the part of the second detection light reflected by the adjustable reflector  304  also satisfy a particular relationship, so as to derive the second predetermined relationship between the power of the first back-reflection light and the power of the second back-reflection light. In an implementation manner of the present invention, the part of the second detection light reflected by the adjustable reflector  304  is divided into the first back-reflection light and the second back-reflection light by 5:5, and the second predetermined relationship is: 
         [0000]        P′   back−reflected   =P″   back−reflected =½ P   r eflected  
 
         [0058]    where Error! Reference source not found. is the power of the first back-reflection light, and Error! Reference source not found. is the power of the second back-reflection light, and Error! Reference source not found. is the power of the part of the first detection light reflected by the adjustable reflector. 
         [0059]    The first optical power meter  302  detects the power of the first detection light, and detects the power of the second back-reflection light by using the second optical power meter. The processor  305  is configured to calculate the power of the input light of the laser  40  according to the power of the first detection light, calculate the power of the first back-reflection light according to the power of the second back-reflection light, and establish and output the power corresponding relationship between the power of the first back-reflection light and the power of the input light of the laser  40 . The processor  305  is further configured to control the adjustable reflector  304  to rotate for N−1 times, to enable the adjustable reflector  304  to be located at N different reflection angles to reflect a part of the first detection light, so as to output N power corresponding relationships, where N is natural number greater than or equal to 2. 
         [0060]    When the adjustable reflector  304  is located at a different reflection angle, a different amount of the second detection light is reflected by the adjustable reflector  304 . Therefore, the power of the second back-reflection light is different, and changes of the input light of the laser  40  may be detected under different back-reflection light. back-reflection light. Further, the processor  305  is further configured to establish a mathematical relationship between the power of the first back-reflection light and the power of the input light of the laser  40  according to the N power corresponding relationships and with reference to a preset mathematical model. 
         [0061]    The detection device  30  further includes a collimating lens  306  and an alarm apparatus  307 . The alarm apparatus  307  is connected to the processor  305 . The processor  305  is further configured to: determine whether the power of the first back-reflection light is greater than or equal to a power threshold value, and if the power of the first back-reflection light is greater than or equal to the power threshold value, control the alarm apparatus  307  to raise an alarm. Certainly, the processor  305  may also control, by using the alarm, the amount of the part of the second detection light reflected by the adjustable reflector  304 , so as to reduce the power of the second back-reflection light, thereby preventing the power of the second back-reflection light from becoming excessively high and preventing a chip of the laser  40  from being damaged. 
         [0062]    The collimating lens  306  is disposed between the second right port  3014  and the adjustable reflector  304 , the collimating lens  306  is configured to collimate the second detection light and output the collimated second detection light to the adjustable reflector  304 , and the part of the second detection light reflected by the adjustable reflector  304  passes through the collimating lens  306  and then be focused into the second left port again. 
         [0063]    In an implementation manner of the present invention, input light of a laser is split into first detection light and second defection light, the first detection light enters a first optical power meter, the second detection light enters an adjustable reflector, the adjustable reflector reflects a part of the first detection light, a part of the second detection light reflected by the adjustable reflector is split into first back-reflection light and second back-reflection light, the first back-reflection light is used as back-reflection light of the laser and returns to the laser, and the second back-reflection light enters the second optical power meter, where power of the first detection light and power of the input light satisfy a first predetermined relationship, and power of the second back-reflection light and power of the first back-reflection light satisfy a second predetermined relationship. Therefore, the power of the input light may be calculated by using the power of the first detection light, and the power of the first back-reflection light is calculated by using the power of the second back-reflection light, so as to establish a corresponding relationship between power of back-reflection light of the laser and the power of the input light of the laser. 
         [0064]    Only implementation manners of the present invention are described above, and are not intended to limit the patent scope of the present invention. Any equivalent variations in structure or equivalent variations in procedure made by using the content of the specification and the accompanying drawings of the present invention or any direct or indirect use in another related technical field similarly fall within the patent protection scope of the present invention.