Mode-hop-free hybrid external-cavity laser with passive thermo-optic coefficient compensation

A system, comprising:

• at least one processor;
• at least one memory coupled to the at least one processor;
• and
• an optical transmitter for communicating optical signals generated by the system, wherein the optical transmitter includes a hybrid laser comprising:
• a reflective gain medium (RGM) comprising an optical gain material coupled with an associated reflector;
• a silicon waveguide;
• a silicon mirror, which is optically coupled to the silicon waveguide;
• a spot-size converter (SSC) comprised of a SSC material, which optically couples the RGM to the silicon waveguide, wherein the SSC converts an optical mode-field size of the RGM to an optical mode-field size of the silicon waveguide;
• wherein the RGM, the spot-size converter, the silicon waveguide and the silicon mirror collectively form a lasing cavity for the hybrid laser;
• wherein an effective thermo-optic coefficient (TOC) of a portion of the lasing cavity that passes through the optical gain material and the SSC material is substantially the same as the TOC of silicon;
• and
• a laser output, which is optically coupled out of the lasing cavity.

A method for operating a hybrid laser, comprising:

• generating an optical signal by powering a reflective gain medium (RGM) comprising an optical gain material coupled with an associated reflector;
• channeling the optical signal through a spot-size converter (SSC) and into a silicon waveguide, wherein the SSC converts an optical mode-field size of the RGM to an optical mode-field size of the silicon waveguide;
• channeling an optical signal from the silicon waveguide into a silicon mirror, which reflects the optical signal back to the RGM to form a lasing cavity;
• and
• optically coupling light from the lasing cavity, which comprises the RGM, the SSC, the optical waveguide, and the silicon mirror, into a laser output;
• wherein an effective thermo-optic coefficient (TOC) of a portion of the lasing cavity that passes through the optical gain material and the SSC material is substantially the same as the TOC of silicon.