Sliding-blade MEMS iris and variable optical attenuator

An iris-type variable aperture fabricated using microelectromechanical systems (MEMS) technology is described. The device contains a number of shutter blades, which are each driven by a separate microactuator, and translated synchronously to create a variable polygonal aperture. The optical performance of devices with different numbers of blades is compared using simple analytic models and diffraction theory. The mechanism is simulated by finite element analysis. Four-blade devices driven by buckling mode electrothermal actuators are formed by double-sided patterning and deep reactive ion etching of bonded silicon-on-insulator and characterized experimentally. Symmetric deflections are obtained, and used to create a square pupil. Variable attenuation is demonstrated using optical fibres with thermally expanded cores.

[1]  D. Marcuse Light transmission optics , 1972 .

[2]  Masaharu Horiguchi,et al.  Thermally-diffused expanded core fibres for low-loss and inexpensive photonic components , 1991 .

[3]  H. Fujita,et al.  Microactuators and micromachines , 1998, Proc. IEEE.

[4]  N. D. de Rooij,et al.  A variable optical attenuator based on silicon micromechanics , 1999, IEEE Photonics Technology Letters.

[5]  Richard M. White,et al.  Microfabricated optical chopper , 1993, Optics & Photonics.

[6]  C. R. Giles,et al.  A fiber connectorized MEMS variable optical attenuator , 1998, IEEE Photonics Technology Letters.

[7]  J. M. Noworolski,et al.  Silicon fusion bonding and deep reactive ion etching: a new technology for microstructures , 1996 .

[8]  V. Milanovic,et al.  Large-displacement vertical microlens scanner with low driving voltage , 2002, IEEE Photonics Technology Letters.

[9]  R. Kasahara,et al.  Lens-free in-line optical isolators. , 1999, Optics letters.

[10]  Y. Gianchandani,et al.  Bent-beam electrothermal actuators-Part I: Single beam and cascaded devices , 2001 .

[11]  Ian Ronald Johnston,et al.  Recent advances in silicon etching for MEMS using the ASE™ process , 1999 .

[12]  Shigeru Tomita,et al.  Characteristics of thermally expanded core fiber , 1996 .

[13]  Bingchu Cai,et al.  Modelling and characterization of diffractive optical propagation inside MEMS variable optical attenuator , 2002, SPIE/COS Photonics Asia.

[14]  Kenneth J. Weible,et al.  Miniaturized imaging systems , 2003 .

[15]  Richard M. White,et al.  Microfabricated optical chopper , 1994 .

[16]  Hiroyuki Fujita,et al.  A piezoelectrically operated optical chopper by quartz micromachining , 1995 .

[17]  R. Vuilleumier,et al.  Variable-entrance-slit system for precision spectrophotometers , 1995 .

[18]  Emil Wolf,et al.  Principles of Optics: Contents , 1999 .

[19]  William C. Tang,et al.  Laterally Driven Polysilicon Resonant Microstructures , 1989 .

[20]  D. Castañón,et al.  Continuous-membrane surface-micromachined silicon deformable mirror , 1997 .

[21]  J. R. Cozens,et al.  Optical Guided Waves and Devices , 1992 .

[22]  M. Sinclair,et al.  A high force low area MEMS thermal actuator , 2000, ITHERM 2000. The Seventh Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.00CH37069).

[23]  J. C. Dainty,et al.  A low cost adaptive optics system using a membrane mirror. , 2000, Optics express.

[24]  N. F. de Rooij,et al.  Megahertz opto-mechanical modulator , 1996 .

[25]  Deepak Uttamchandani,et al.  Design and evaluation of a MEMS optical chopper for fibre optic applications , 2004 .