Power monitor for silicon-photonics-based laser

A method for forming a silicon-photonics-based laser device with a power monitor inside the laser cavity comprising:

• providing a silicon substrate with embedded waveguides;
• forming a wavelength tuner based on the embedded waveguides, including at least a reflector configured with high reflectivity;
• forming a splitter waveguide in the silicon substrate next to a section of the embedded waveguides right in front of the reflector;
• forming a photodiode in the silicon substrate to couple with the splitter waveguide;
• providing a semiconductor laser gain chip having an active region bounded between a frontend in low reflectivity and backend with anti-reflective characteristics;
• mounting the semiconductor laser gain chip to the silicon substrate to have the backend coupled to the wavelength tuner to form an extended cavity between the frontend and the reflector;
• and
• measuring power of light right in front of the reflector by the photodiode to monitor output power of laser out of the frontend.