DISTRIBUTED FEED-BACK TYPE SEMICONDUCTOR LASER

PURPOSE:To obtain the stabilized single wavelength operation and the excellent input characteristics for the titled semiconductor laser by a method wherein a semiconductor, having the forbidden and width wider than that of a light-emitting layer, is uniformly arranged in the thickness heavier than that of the region on the extended part of the region where light is actually distributed. CONSTITUTION:InP layers 10 and 10a are buried on the extended part of the end parts 11 and 11a of a laser region. The light emitted from the end part 11a is widely spreaded on the InP layer 10a of the length l2 part, reflected from the emission end face 9a of an element, and the light which will be fed back to the laser region is very small. Accordingly, the F-p resonator consisting of the terminals 9 and 9a of the emitted light receives a heavy loss and its oscillation is suppressed. As a result, the single wavelength operation of a DFB laser can be accomplished. On the other hand, as the InP layer 10 is transparent for the outputted light, the input-output characteristics having an excellent linearity can be obtained.