Highly external optical feedback tolerant 1.49 μm single-mode lasers with partially corrugated gratings

A 1490 nm InGaAsP single-mode laser diode, with high endurance against external optical feedback, was realized utilizing an optimized partially corrugated grating and a window-mirror-structure. The grating’s length and the coupling coefficient were designed to enable moderate output power, low feedback sensitivity and a SMSR of 40dB simultaneously. The relative intensity noise (RIN) was maintained less than −120 dB/Hz under strong external optical feedback as high as −10 dB.