| 摘要 |
PURPOSE:To dissolve the destabilization of laser oscillation due to the reflected light as well as to suppress the optical crosstalk by a method wherein the planes of incidence of at least the central parts of the front end surfaces, which oppose to the ear end surfaces of the semiconductor lasers, of the monitor photo diodes are formed into inclined planes in such a way as to be cut inside over a range as wide as possible. CONSTITUTION:The groove width of a groove 14 separating a semiconductor laser and a monitor photo diode in each group of a plurality of groups of the semiconductor lasers L1-L3 and the monitor photo diodes P1-P3 is adequately narrowed and the planes equivalent to incidence on the front end surfaces of the monitor photo diodes P1-P3 are formed into inclined planes 15 in such a way as to be cut inside over a range as wide as possible to the rear end surfaces, from which back beams RP1-RP3 are emitted, of active regions AR1-AR3 in the semiconductor lasers L1-L3. Even though the back beams RP1-RP3 to be incided are somewhat reflected, the possibility that these are returned to the active regions AR1-AR3 in the semiconductor lasers L1-L3 is eliminated, the oscillation state in the semiconductor laser L1-L3 is stabilized, and at the same time, the groove width of the grooves 14 is narrowed. Thereby, the mutual leakage of light into the adjoining monitor photo diodes P1-P3 can be prevented and the optical crosstalk can be effectively suppressed. |
