Continuously tunable long-wavelength MEMS-VCSEL with over 40-nm tuning range

This letter presents for the first time an electrically pumped tunable vertical-cavity surface-emitting laser (VCSEL) with a record-breaking tuning range of 40 nm at long wavelengths. The VCSEL is based on a two-chip concept. The laser peak can be tuned continuously and without mode-hopping in a wavelength range above 1.55 μm due to a microelectromechanical movable mirror membrane. The VCSEL is single mode all over the tuning range with a 32-dB sidemode suppression ratio. The laser emits a maximum output power of 100 μW in continuous-wave operation at room temperature. Dynamic measurements of the tuning characteristics show that the 3-dB cutoff frequency for an electrothermal wavelength modulation is about 500 Hz and the 1/e-time constant of the step response is about 1 ms.