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 $2.0\mathrm{mm}\times 1.5\mathrm{mm}\times 0.6\mathrm{mm}$ , and has obtained a tuning range of $30.3\mathrm{nm}$ with a resolution of $0.03\mathrm{nm}∕{\mathrm{V}}^2$ , a maximum power of $0.4\mathrm{dBm}$ and a side mode suppression ratio of $26\mathrm{dB}$ . Other merits include fast tuning speed, improved mechanical/wavelength stability, batch fabrication, and low cost.