| 摘要 |
A semiconductor diode laser amplifier (100) includes an active layer (4) which is situated between two cladding layers (1A, (3,6)) and in which a strip-shaped active region is present which is bounded in longitudinal direction by two end faces (7,8) which are practically perpendicular to the active region and are provided each with an antireflection layer (71,81). The amplification ripple of such a laser amplifier (100) is comparatively high, in particular when radiation of different wavelengths is present in the laser (100), such as the TE and TM portions of the radiation to be amplified. In a laser amplifier (100), a first end face (7) is provided with a first antireflection layer (71) which has a minimum reflection at a first wavelength, for example that at which the reflection is a minimum for the TE polarized portion of the radiation to be amplified, and the second end face (8) is provided with a second antireflection layer (81) which has a minimum reflection at a second wavelength different from the first, for example that at which the reflection is a minimum for the TM polarized portion of the radiation to be amplified. The product of the reflections is a minimum for both wavelengths as a result of this, at least lower than in the known laser (100) in which both end faces (7,8) are provided with an identical antireflection layer (71,81) which is optimized for an intermediate wavelength. The laser (100) has a particularly low amplification ripple because this ripple is indeed proportional to the square root of said product of reflections. Good results are obtained with antireflection layers (71,81) which include only a single layer, preferably made of silicon oxynitride.
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