Tunable laser using micromachined grating with continuous wavelength tuning

This letter develops a method that is able to optimize the grating pivot position to obtain maximum continuous tuning range for a Littrow laser, and also verifies the method by implementation of a single-chip integrated laser using the microelectromechanical systems (MEMS) technology. The laser consists of a semiconductor gain chip, a microlens, and a MEMS blazed grating arranged in the Littrow configuration. The laser is integrated onto a single silicon chip while maintaining the ability of continuous tuning in a large range. It has a compact size of 2.0 mm × 1.5 mm × 0.6 mm, and has obtained a tuning range of 30.3 nm with a resolution of 0.03 nm/V2, a maximum power of 0.4 dBm and a side mode suppression ratio of 26 dB. Other merits include fast tuning speed, improved mechanical/wavelength stability, batch fabrication, and low cost.