Tunable Lasers Phaselocked to Optical Frequency Comb

The demand for stable and tunable laser sources is steadily growing across a wide range of applications. Optical Frequency Combs (OFCs) have emerged as a powerful reference standard, offering stable frequency spacing between the comb tones or high optical frequency stability. To obtain low-cost tunable lasers with their carriers or relative frequencies locked, we phaselocked a commercial Telecom grade Integrable-Tunable-Laser-Assembly (ITLA) to an OFC. We demonstrate such phaselock within the telecom C-band (1527 nm - 1565 nm), using sub-mW OFC power corresponding to per-tone power down to nW regime. This enables phaselocking of large number of tunable lasers to the same OFC via passive splitting of the OFC power. We achieved short-term integrated phase noise of 10 mrad and long-term frequency stability measured over 10 hours below ± 0.01 Hz.