We report a MEMS optical tunable filter based on high-aspect-ratio etching of sub-wavelength silicon layers on a silicon- on-insulator wafer. The reported filter has measured free-spectral and filter-tuning ranges of approximately 100 nm and a finesse of about 20 around a wavelength of 1550 nm, enabled by the use of 1000 nm-thick silicon layers and a balanced tilt-free motion using a lithographically-aligned electrostatic actuator. The average insertion loss of the filter is about 12 dB with a superior wavelength-dependent loss of about 1.5 dB. The filter has an out-of-band to in-band wavelength rejection ratio that is better than 20 dB. The reported filter experimental characteristics and its integrability are suitable for the production of integrated swept sources for optical coherence tomography application and miniaturized spectrometers.

Date Published: 7 March 2014
PDF: 8 pages
Proc. SPIE 8977, MOEMS and Miniaturized Systems XIII, 89770V (7 March 2014); doi: 10.1117/12.2040767

Published in SPIE Proceedings Vol. 8977:
MOEMS and Miniaturized Systems XIII
Wibool Piyawattanametha; Yong-Hwa Park, Editor(s)