Semiconductor diode laser, in particular a laser amplifier, and method

Abstract

The invention relates to a III-V laser (amplifier) with an active region (4A) which encloses a small angle with the end faces (50, 51), is separated therefrom by a preferably current-blocking cladding layer (5) and has a tapering end (40) of which a first side face (42) coincides with a side face (42) of the remainder of the strip-shaped active region (4A), while a second side face (43) thereof encloses an acute angle with the perpendicular to the end faces (50, 51). Such a laser has an amplification ripple, which is undesirable. In a laser according to the invention, the second side face (43) of the tapering portion (40) encloses an angle with the perpendicular to the end face (50, 51) which lies between 0.degree. and 30.degree., preferably between 0.degree. and 10.degree., and which is preferably approximately 0.degree.. The laser according to the invention has a particularly low reflection, as a result of which said amplification ripple is absent or at least very small. No differences in growing processes against said side faces occur since both the first and the second side face (42, 43) of the active region (4A) are mutually substantially parallel. Accordingly, the laser is preferably of the buried hetero type. In that case, the growth around the active region (4A) is very homogeneous, which benefits the yield and quality of the lasers. The laser is preferably constructed as an amplifier, for which purpose the end faces (50, 51) are provided with an anti-reflection layer. The invention, finally, also relates to a method by which the desired laser is obtained in a simple manner.