Monolithically Integrated 4-Channel-Selectable Light Sources Fabricated by the SAG Technology

The monolithic integration of four 1.5-μm InGaAsP/InP distributed feedback (DFB) lasers with a 4 × 1 multimode-interference (MMI) optical combiner using the selective area growth and butt-joint regrowth technologies is proposed and demonstrated. A dry-etching stop layer is grown to guarantee the etching depth of MMI. The four channels could match the ITU wavelength grid of 200-GHz well with a simple integrated thin-film heater, covering the wavelength range of 1552.3-1556.3 nm. The average output power of LD is 2.8 mW with a 150-mA current, and the threshold current is 20-22 mA at 25°C. The four channels can operate separately or simultaneously.