Laser module, control method of the same, control data of the same, and control data generation method

Abstract

A laser module includes a semiconductor laser, an output optical system provided on an optical output side of the semiconductor laser, a temperature detecting element that detects a temperature of the output optical system; and an output controller that calculates a drive current to set an optical output intensity of the laser module at a desired value on the basis of temperature information obtained by the temperature detecting element, and outputs the drive current to the semiconductor laser.

1 . A generation method of control data including a semiconductor laser, an output optical system provided on an optical output side of the semiconductor laser, a temperature detecting element that detects a temperature of the output optical system, and a light receiving element that detects a monitor optical intensity, the control method comprising the steps of:
 controlling an optical output to keep the monitor optical intensity constant on the basis of information on the monitor optical intensity obtained from the light receiving element;   measuring a change amount of an optical output intensity output from the output optical system before and after the temperature of the output optical system changes, in a state where the step of controlling the optical output is implemented; and   obtaining optical output intensity correction information that is the control data to correct a difference in the optical output intensity before and after the temperature of the output optical system changes, with the information on the change amount of the optical output intensity measured.   
     
     
         2 . A generation method of control data to control a laser module including a semiconductor laser, an output optical system provided on an optical output side of the semiconductor laser, and a temperature detecting element that detects a temperature of the output optical system, the generation method comprising:
 calculating a change in an optical loss of the output optical system before and after the temperature of the output optical system changes, on the basis of a physical constant of the output optical system; and   obtaining optical output intensity correction information that is the control data to correct a difference in an optical output intensity before and after the temperature of the output optical system changes, with the information on the change in the optical loss calculated.   
     
     
         3 . A generation method of control data to control a laser module including a semiconductor laser, an output optical system provided on an optical output side of the semiconductor laser, and a temperature detecting element that detects a temperature of the output optical system, the generation method comprising:
 obtaining a change amount of an outer shape of the output optical system before and after the temperature of the output optical system changes;   calculating a change in an optical loss of the output optical system before and after the temperature of the output optical system changes, on the basis of information on the change amount obtained; and   obtaining optical output intensity correction information that is the control data to correct a difference in an optical output intensity before and after the temperature of the output optical system changes, with the information on the change in the optical loss calculated.   
     
     
         4 . The generation method as claimed in  claim 2 , further comprising a step of generating the optical output intensity correction information, by an interpolation method, of the temperature between different temperatures of the output optical system, the different temperatures being obtained multiple times. 
     
     
         5 . The generation method as claimed in  claim 4 , wherein the different temperatures include an upper limit temperature and a lower limit temperature, when the laser module is used. 
     
     
         6 . The generation method as claimed in  claim 2 , wherein the step of obtaining the optical output intensity correction information is implemented only on a specific module out of multiple laser modules that use the optical output intensity correction information. 
     
     
         7 . The generation method as claimed in  claim 2 , wherein the laser module further includes a wavelength controller that controls a wavelength of the semiconductor laser, further comprising steps of:
 obtaining a change amount of an emission wavelength of the semiconductor laser generated by correcting a drive current of the semiconductor laser on the basis of the optical output intensity correction information; and   obtaining correction information of the wavelength controller to correct the change amount.   
     
     
         8 . Control data to control a laser module including a semiconductor laser, an output optical system provided on an optical output side of the semiconductor laser, and a temperature detecting element that detects a temperature of the output optical system, the control data comprising optical output intensity correction information that is the control data to correct a difference in an optical output intensity before and after the temperature of the output optical system changes, on the basis of a change in an optical loss of the output optical system. 
     
     
         9 . The control data as claimed in  claim 8 , wherein the optical output intensity correction information is provided for multiple temperatures between an upper limit temperature and a lower limit temperature of the laser module. 
     
     
         10 . The control data as claimed in  claim 8 , wherein multiple temperatures are determined to control the laser module, and the optical output intensity correction information is provided for said multiple temperatures determined. 
     
     
         11 . The control data as claimed in  claim 8 , wherein the laser module further includes a wavelength controller that controls a wavelength of the semiconductor laser, further comprising correction information of the wavelength controller to correct a change amount of an emission wavelength of the semiconductor laser generated by correcting a drive current of the semiconductor laser on the basis of the optical output intensity correction information.