Reduction of waveguide facet reflection in optical hybrid integrated circuit using saw-toothed angled facet

A saw-toothed facet structure is proposed to reduce the waveguide facet reflection in an optical hybrid integrated circuit. This structure was used to achieve the hybrid integration of a semiconductor laser amplifier (SLA) on a planar lightwave circuit (PLC) platform. Gain ripple for a flat facet was reduced from 3.6 dB to 0.6 dB by setting a facet angle of 35 degrees. The SLA insertion loss was 3.5 dB at 0 degrees and 4.0 dB at 35 degrees with an SLA injection current of 80 mA. Thus the sawtoothed facet is confirmed to reduce facet reflection effectively without significant insertion loss increase.<
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