REDUCTION OF WAVE-GUIDE 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 Bat 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 saw-toothed facet is confirmed to reduce facet reflection effectively without significant insertion loss increase.