SU-8 Optical Accelerometers

This paper presents the optimization and characterization of SU-8 quad beam optical accelerometers based on intensity modulation. An applied acceleration causes a misalignment between three waveguides, resulting in variation of losses. Mechanical simulations have focused on the evaluation of sensitivity and the design of a robust junction between the mechanical beams and the inertial mass. Results demonstrate that perfectly rounded structures show at least 4.4 times less stress than L-shaped counterparts. Optical simulation predicts that the optimal configuration in terms of sensitivity is obtained when the waveguides are not completely misaligned, since then losses are insensitive to variations in acceleration. Numerical sensitivities ranging between 11.12 and 32.14 dB/g have been obtained. Fabrication has been simplified, now requiring only two photolithographic steps and electroplating Cu as a sacrificial layer. Experimental results show a reproducible experimental sensitivity of at least 13.1 dB/g

[1]  Youngchul Chung,et al.  Analysis of Z-invariant and Z-variant semiconductor rib waveguides by explicit finite difference beam propagation method with nonuniform mesh configuration , 1991 .

[2]  E. Abbaspour-Sani,et al.  A novel optical accelerometer , 1995, IEEE Electron Device Letters.

[3]  Gregory N. De Brabander,et al.  Micromachined silicon cantilever beam accelerometer incorporating an integrated optical waveguide , 1993, Other Conferences.

[4]  Sylvain Ballandras,et al.  Lateral optical accelerometer micromachined in (100) silicon with remote readout based on coherence modulation , 1998 .

[5]  Dong-Woo Cho,et al.  Development of a micro-opto-mechanical accelerometer based on intensity modulation , 2004 .

[6]  R. Feng,et al.  Influence of processing conditions on the thermal and mechanical properties of SU8 negative photoresist coatings , 2002 .

[7]  Ramu V. Ramaswamy,et al.  Modeling of graded-index channel waveguides using nonuniform finite difference method , 1989 .

[8]  Tadasi Sueta,et al.  Integrated Optic Accelerometer Employing a Cantilever on a Silicon Substrate , 1989 .

[9]  Y. Kanda,et al.  A graphical representation of the piezoresistance coefficients in silicon , 1982, IEEE Transactions on Electron Devices.

[10]  S. Buttgenbach,et al.  Polymer microlenses with modified micromolding in capillaries (MIMIC) technology , 2005, IEEE Photonics Technology Letters.

[11]  S R Carneiro,et al.  Two-mode optical fiber accelerometer. , 1992, Optics letters.

[12]  Bruce K. Gale,et al.  Micro-structure mechanical failure characterization using rotating Couette flow in a small gap , 2005 .

[13]  Chen Jian,et al.  Analysis on twin-mass structure for a piezoresistive accelerometer☆ , 1992 .

[14]  N. D. Rooij,et al.  All-photoplastic, soft cantilever cassette probe for scanning force microscopy , 2000 .

[15]  Willy Sansen,et al.  A combined silicon fusion and glass/silicon anodic bonding process for a uniaxial capacitive accelerometer , 1992 .

[16]  Stephanus Büttgenbach,et al.  Fabrication and investigation of in-plane compliant SU8 structures for MEMS and their application to micro valves and micro grippers , 2002 .

[17]  P. Bidaud,et al.  Fabrication and characterization of an SU-8 gripper actuated by a shape memory alloy thin film , 2003 .

[18]  Bingchu Cai,et al.  A novel device of passive and fixed alignment of optical fiber , 2004 .

[19]  F. Horst,et al.  Adaptive gain equalizer in high-index-contrast SiON technology , 2000, IEEE Photonics Technology Letters.

[20]  Joseph Zyss,et al.  Single-mode TE00-TM00 optical waveguides on SU-8 polymer , 2004 .

[21]  Stephanus Büttgenbach,et al.  Application and Investigation of In-Plane Compliant SU8-Structures for MEMS , 2001 .

[22]  M. Laudon,et al.  Mechanical characterization of a new high-aspect-ratio near UV-photoresist , 1998 .

[23]  T. K. Gangopadhyay,et al.  Prospects for Fibre Bragg Gratings and Fabry-Perot Interferometers in fibre-optic vibration sensing , 2004 .

[24]  Ashwin A. Seshia,et al.  A vacuum packaged surface micromachined resonant accelerometer , 2002 .

[25]  Jian Zhang,et al.  Polymerization optimization of SU-8 photoresist and its applications in microfluidic systems and MEMS , 2001 .

[26]  J. Esteve,et al.  BESOI-based integrated optical silicon accelerometer , 2004, Journal of Microelectromechanical Systems.

[27]  S. Buttgenbach,et al.  Integrated polymer optical accelerometer , 2005, IEEE Photonics Technology Letters.

[28]  Jerzy Kalenik,et al.  A cantilever optical-fiber accelerometer , 1998 .

[29]  Toshihiko Baba,et al.  Dispersion and radiation loss characteristics of antiresonant reflecting optical waveguides-numerical results and analytical expressions , 1992 .

[30]  R. Melamud,et al.  Development of an SU-8 Fabry-Perot blood pressure sensor , 2005, 18th IEEE International Conference on Micro Electro Mechanical Systems, 2005. MEMS 2005..

[31]  Francis E. H. Tay,et al.  A novel micro-machining method for the fabrication of thick-film SU-8 embedded micro-channels , 2001 .

[32]  T. Koch,et al.  Antiresonant reflecting optical waveguides in SiO2‐Si multilayer structures , 1986 .

[33]  N. Daldosso,et al.  Comparison among various Si/sub 3/N/sub 4/ waveguide geometries grown within a CMOS fabrication pilot line , 2004, Journal of Lightwave Technology.