Precise determination of turning mirror loss using GaAs/AlGaAs lasers with up to ten 90 degrees intracavity turning mirrors

The authors report the fabrication and testing of GaAs/AlGaAs ridge-waveguide lasers with two, six, and ten 90 degrees intracavity turning mirrors using temperature-controlled chemically assisted ion beam etching. By measuring the laser threshold current as a function of the number of mirrors over an entire 1-cm/sup 2/ wafer, the authors make a very reliable estimate of the average single-pass turning mirror loss of 1.16+or-0.14 dB/mirror. Comparison with theory shows that the etched facets have a very small RMS surface roughness of less than 150 AA.<
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