SEMICONDUCTOR LASER AMPLIFIER

摘要

PURPOSE:To obtain a sufficient amplification gain with a short device length and change the taking-out direction of a light in a substrate surface and facilitate a high integrity by a method wherein an angle formed by a waveguide and an end surface is so selected as to make the incident angle of a laser beam propagated in the waveguide against the end surface larger than a critical angle. CONSTITUTION:An n-type InP first cladding layer 2, an InGaAsP active layer 3 and P-type InP second cladding layer 4 are successively built up on an n-type InP semiconductor substrate 1. The thicknesses of the parts of the second cladding layer corresponding to waveguide are increased a little. With this construction, a light confining cladding part 8 is formed. The waveguide is bent at both the end surfaces 9 and 10 and formed into a zig-zag shape. Angles formed by the waveguides and the end surfaces 9 and 10 are so selected as to make the incident angle of an incident laser beam against the end surfaces 9 and 10 larger than a critical angle. Therefore, the incident laser beam is totally reflected by the end surface 10 which functions as a totally reflective surface 11 and guided into the other waveguide. Further, the laser beam is totally reflected by the end surface 9 and taken out from the end surface 10 through a non-reflective coating film.