MEMS Tunable Coupled-Cavity Laser

This paper presents a MEMS based tunable coupled-cavity laser (CCL), which employs a deep-etched parabolic mirror to adjust the gap of the CCL for optimal phase match. In experiment, such mirror measures an initial coupling efficiency of 70.5% and a low variation (<5 %) of the efficiency even when the mirror is translated by 20 μm, which is ideal for the CCL to change the cavity length (i.e., phase condition) without deteriorating the optical coupling. Stable single-mode laser output over 6.5 nm is demonstrated. Compared with the traditional CCLs that have fixed air gap, this design offers an additional degree of freedom to adjust the CCL to its optimal tuning state.