STRAIN-TUNING OF OPTICAL DEVICES WITH NANOMETER RESOLUTION

We stretched diffractive gratings by thin-film piezoelectric actuators, and demonstrated observable changes in grating period with sub-nanometer resolution. Characterization of fabricated MEMS devices suggests that strain-tuning can be widely used to make silicon optical devices tunable. Due to the virtual absence of electro-optic and charge carrier effects in silicon, thermo-optics has been the only means so far to achieve tunability. Mechanical strain-tuning would provide a faster response time, a lower power consumption and better localization of tunability, permitting fine tuning to fabrication mismatches, and active compensation to external disturbances. A first tunable microcavity photonic crystal is developed with a maximum strain of 0.21% to achieve 12 nm tuning of the resonant wavelength for C-band optical signals.