METHOD AND SYSTEM FOR TESTING WAVELENGTH VARIABLE SEMICONDUCTOR LASER, AND METHOD FOR TESTING COHERENT LIGHT SOURCE

摘要

PROBLEM TO BE SOLVED: To provide a method capable of easily and rapidly estimating wavelength variable properties of a wavelength variable semiconductor laser. SOLUTION: The test system is composed of a power source that supplies current to the wavelength variable semiconductor laser 1 which is made up of an active region, a phase adjusting region and a DBR region, a photo detecting element 3 that detects the intensity of output from the semiconductor laser, and a transmissive element for selecting wavelength 6 that can be inserted in an optical path extending to the photo detecting element. At least one of phase current injected into the phase adjusting region and DBR current injected into the DBR region is varied, and then the intensity of output of the semiconductor laser at the back of the transmissive element for selecting wavelength is detected by the photo detecting element in such conditions that a constant quantity of active current is injected into the active region, and the transmissive element for selecting wavelength is inserted in the optical path from the semiconductor laser to the photo detecting element. Then, the phase current and the DBR current corresponding to changing points in the intensity of output are obtained, and thereby the stability or the like of the wavelength variable DBR semiconductor is checked easily and rapidly.