Hybrid-Integrated Wavelength and Reflectivity Tunable III–V/Silicon Transmitter

We demonstrate a novel wavelength-tunable hybrid external cavity silicon-based transmitter with integrated reflectivity tunable mirror. First, designs of a novel hybrid laser based on reflective symmetric and asymmetric Mach-Zehnder interferometer-based mirrors are studied with single- and double-ring intracavity filters, respectively. Asymmetric configuration is used in order to increase the tuning range of a single-ring laser by more than 90%. Furthermore, adjustment of the mirror reflectivity allows for control of laser characteristics, such as threshold current, wall-plug efficiency, output power, and linewidth. Finally, an ultracompact hybrid tunable III-V/Si transmitter with more than 28-nm tuning range is then demonstrated based on such hybrid cavity design and one ring modulator. We successfully achieved modulation up to 40 Gb/s and transmission over 20 (100) km at 25 (10) Gb/s.