Optical coherent transmitter on a silicon chip

A method for coherent optical transmission, the method comprising:

• receiving, by a coherent modulator, a local oscillator (LO) optical signal from a tunable laser co-disposed with the coherent modulator on a silicon photonics chip;
• modulating, by the coherent modulator, a determined optical signal and the LO optical signal to produce a modulated optical signal;
• transmitting with a transmitter co-disposed with the tunable laser and the coherent modulator on the silicon photonics chip, the modulated optical signal;
• and
• wherein the coherent modulator includes a microring modulator.

A system comprising:

• an apparatus comprising:
• a tunable laser to output a light beam;
• a coherent modulator optically coupled with the tunable laser to modulate the light beam;
• an optical transmitter optically coupled with the coherent modulator to transmit the modulated light beam;
• and
• wherein the tunable laser, the coherent modulator, and the optical transmitter are integrated on a silicon photonics chip;
• an optical waveguide coupled with an optical output of the optical transmitter to transmit the modulated light beam to another device;
• and
• wherein the coherent modulator includes differential microring modulators.