OPTICAL POWER MEASURING METHOD AND DEVICE

摘要

PROBLEM TO BE SOLVED: To perform accurate measurements in a short time. SOLUTION: The sensitivity C (λj) of an output signal to the received light wavelengthλj of a photodetector is previously stored (30), and a current I supplied for a semiconductor laser is provided with values I1 and I2 (31). The wavelengthλof light outputted from the semiconductor laser is measured asλ1 andλ2 by a wavelength measuring device (32). On the basis of the wavelengthsλ1 andλ2 at the current values I1 and I2, the parameter (m) of the relational expressionλ=f (I) between the previously provided wavelengthλand the current I is determined (33). A current Ik is changed (34) to measure the output Pk of the photodetector. The wavelengthλk is estimated by the relational expressionλk=f(Ik) (33). C (λk) is obtained from the sensitivity C (λj) and the wavelengthλk by interpolation computations (35). By correcting the output Pk of the photodetector by the sensitivity Ck=C (λk), optical power Pk/Ck is obtained (36) and outputted (37).