High-speed, directly-modulated widely tunable 1310 nm coupled cavity laser via multimode interference

We discuss the design and demonstration of a widely tunable laser operating at 1310 nm with ∼38 nm tuning range, u003e35 dB side-mode-suppression-ratio (SMSR), and output powers of ∼3 mW per tuning wavelength. Greater than 50 channels are demonstrated on a material platform that consists of In 0.70 Al 0.17 Ga 0.13 As multiple quantum wells (MQW) and Al 0.52 In 0.48 As electron stop layers for high temperature operation. Various single-side facet power wall-plug-efficiency (WPE) values of 8–1% are reported for operating temperatures of 30–70 °C, respectively. We compare theoretical and experimental data on the impact that multi-mode-interference (MMI) coupling coefficient values have on SMSR. We also discuss the integration of on-chip mode-converters to facilitate low-loss edge coupling to silicon photonic integrated circuits (Si-PICs). Directly-modulated, small-signal frequency measurements show 3-dB modulation bandwidths up to 14 GHz. The absence of epitaxial re-growth and lithographically demanding sub-wavelength gratings lends itself to high operating temperature, reliable and low-cost tunable light sources with device sizes of ∼400 μm × 300 μm.