MEMS optical tunable filter based on free-standing subwavelength silicon layers

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.

[1]  J. Izatt,et al.  Swept source optical coherence tomography using an all-fiber 1300-nm ring laser source. , 2005, Journal of biomedical optics.

[2]  G. Guillot,et al.  Highly selective and widely tunable 1.55-μm InP/air-gap micromachined Fabry-Perot filter for optical communications , 1998, IEEE Photonics Technology Letters.

[3]  G. Lammel,et al.  MEMS infrared gas spectrometer based on a porous silicon tunable filter , 2001, Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090).

[4]  A. Poulin,et al.  Advances in Modeling, Design, and Fabrication of Deep-Etched Multilayer Resonators , 2012, Journal of Lightwave Technology.

[5]  Wolfgang Drexler,et al.  Optical coherence tomography: Technology and applications , 2013, 2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC.

[6]  D. Sadot,et al.  Tunable optical filters for dense WDM networks , 1998, IEEE Commun. Mag..

[7]  Yasuyuki Inoue,et al.  Digitally tunable optical filters using arrayed-waveguide grating (AWG) multiplexers and optical switches , 1997 .

[8]  C.A. Burrus,et al.  WDM channel monitoring and signal power control/equalization using integrated tunable active filters , 1997, 1997 Digest of the IEEE/LEOS Summer Topical Meeting: Vertical-Cavity Lasers/Technologies for a Global Information Infrastructure/WDM Components Technology/Advanced Semiconductor Lasers and Application.

[9]  Yasser M. Sabry,et al.  In-plane external fiber Fabry–Perot cavity comprising silicon micromachined concave mirror , 2013 .

[10]  H. Hillmer,et al.  Ultralow biased widely continuously tunable fabry-Perot filter , 2003, IEEE Photonics Technology Letters.

[11]  Yasser M. Sabry,et al.  In-plane diffraction loss free optical cavity using coated optical fiber and silicon micromachined spherical mirror , 2013, Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components.

[12]  Yasser M. Sabry,et al.  Silicon micromirrors with three-dimensional curvature enabling lensless efficient coupling of free-space light , 2013, Light: Science & Applications.

[13]  J. Fujimoto,et al.  Optical coherence tomography using a frequency-tunable optical source. , 1997, Optics letters.

[14]  V. A. Konovalov,et al.  Tunable optic filter based on liquid crystals , 2002, Proceedings of LFNM 2002. 4th International Workshop on Laser and Fiber-Optical Networks Modeling (IEEE Cat. No.02EX549).

[15]  Chester Shu,et al.  Wavelength-tunable active mode locking of a novel fiber laser including fiber gratings , 1998, Technical Digest. Summaries of Papers Presented at the Conference on Lasers and Electro-Optics. Conference Edition. 1998 Technical Digest Series, Vol.6 (IEEE Cat. No.98CH36178).

[16]  M. Kubota,et al.  Free-Space Tunable and Drop Optical Filters Using Vertical Bragg Mirrors on Silicon , 2006, IEEE Journal of Selected Topics in Quantum Electronics.