MONOLITHIC SEMICONDUCTOR LASER DIODE AND PHOTODIODE STRUCTURE

摘要

PURPOSE: To perform screening of a laser diode on a wafer with reference to a mode stability by imparting a spatially uneven sensitivity profile of incident light beam to a photodiode such that the photodiode current depends on the intensity distribution of light impinging on the photodiode. CONSTITUTION: A structural body 20 comprises the front and rear ends 16A, 16B of a laser diode 11, and a pair of photodiodes 12A, 12B disposed oppositely thereto. Both of them have a spatially nonuniform sensitivity profile and the photodiode faces 21, 22 have opposite profiles. Similarly to the face 22, the face 21 serves as a sensor having spatially nonuniform sensitivity and the photodiode 12A exhibits a lowest sensitivity in the center and whereas the photodiode 12B exhibits a highest sensitivity in the center. These photodiodes detect a variation of mode in the laser because it causes a variation of light intensity distribution.