Widely tunable 1.5 µm micromechanical opticalfilter usingAlO x /AlGaAs DBR

The authors demonstrate, for the first time, a wavelength tunable optical filter at 1.55 µm using micromechanical tuning of a Fabry-Perot resonator with an AlOx/AlGaAs distributed Bragg reflectors (DBR). The use of thermally oxidised AlAs layers, resulting an ultrawide bandwidth, dramatically increased the tuning range and efficiency of the resonator. Very efficient continuous tuning of > 50 nm with only a 0.95 V tuning voltage was achieved. The tuning range, limited by our test laser, is expected to be expandable to hundreds of nm.