A novel optical lamellar grating out-of-plane microgyroscope

This paper demonstrates the realization of a novel lamellar grating out-of-plane gyroscope design. The sensing mechanism is based on out-of-plane motion of movable light-reflecting beams changing the phase relationship between the light reflected off the two sets of beams. This phase relationship is manifested as an intensity change in the zeroth-order diffracted light. The device consists of two in-plane 180deg out-of-phase vibrating masses with a set of overlapping light-reflecting beams behaving essentially as a lamellar grating. The device was fabricated based on the SOI-MUMPS process. The gyroscope demonstrated a sensitivity of 17.8 muV/(deg/s) and linearity error of less than 0.6%. The results have great potential to be improved through the use of more stable lasers, vacuum operation and better fabrication control.