1 × 8 MMI based multi-channel interference laser integrated with SOA through a 2-port multimode interference reflector.

A 1 × 8 multimode interferometer (MMI) based multi-channel interference (MCI) widely tunable laser integrated with semiconductor optical amplifier (SOA) through a 2-port multimode interference reflector (MIR) is reported in this paper. The 2-port MIR can be fabricated with deeply etched waveguides of the MCI laser with no extra fabrication process, which decreases the fabrication complexity greatly. To reduce the loss arising from mode mismatch between surface and deep ridge waveguides, a tapered shallow-deep transition structure is designed and fabricated with a loss of 0.09 dB ± 0.03 dB. The MCI laser with integrated SOA achieves a tuning range of 52.5 nm with side mode suppression ratios higher than 40 dB across the tuning range and more than 13 dBm output power coupled into a lensed fiber at room temperature.