Low threshold 980-nm tunable vertical-cavity surface-emitting lasers

Low threshold, continuous wavelength tuning micro-electro-mechanically system (MEMS) tunable vertical-cavity surface-emitting lasers (VCSELs) operating at 980 nm are demonstrated. The device utilizes the two-chip concept with a MEMS membrane mirror suspended by an air gap above a VCSEL amplifier. Output power of 4.56 mW with 14 mu m diameter oxide aperture in continuous operation and tuning range of 6.8nm are obtained. Due to the low optical loss in resonance cavity results in threshold current as low as 0.6 mA at room temperature. Theoretical calculation for the threshold gain as a function of the wavelength and air gap is obtained respectively, which provides the design strategies to improve device performance.