Widely tunable silicon-fiber laser at 2 µm.

Laser sources operating in the 2 µm spectral region play an important role for sensing and spectroscopy, and potentially for optical communication systems. In this work, we demonstrate a widely tunable hybrid silicon-fiber laser operating in the 2 µm band. By introducing a silicon-integrated Vernier filter in a fiber laser, we achieved continuous wavelength tuning over a range of 100 nm, from 1970 to 2070 nm. Fiber-coupled output power up to 28 mW was measured with a full-width-half-maximum linewidth smaller than 260 kHz and a side-mode-suppression ratio greater than 40 dB over the spectral range.