Micromechanical fiber-optic attenuator with 3 /spl mu/s response

Optomechanical fiber-optic attenuators are bulky and slow. The mechanical antireflection switch (MARS) modulator offers a high-speed alternative for applications including dynamic gain control in fiber amplifiers. This paper describes a compact electrically controlled variable attenuator using a micromechanical device where electrostatic deflection of a silicon nitride quarter-wave dielectric layer suspended over a silicon substrate creates a variable reflectivity mirror. This device is packaged with two fibers in one ceramic ferrule placed in contact with a gradient index (GRIN) collimation lens, so that the input light reflects from the modulator in the collimated beam plane and couples into the output fiber. Using a 300 /spl mu/m diameter MARS attenuator and a 500 /spl mu/m diameter collimation lens, the total insertion loss at 1550 nm was 3.0 dB with no applied voltage, increasing to 31 dB at 35.2 V. The polarization dependent loss was less than 0.06 dB. Full attenuation with more than 100 mW input power produced no damage. The response time was 2.8 /spl mu/s to move from maximum to minimum transmission and 1.1 /spl mu/s to return to maximum transmission.

[1]  Joseph E. Ford,et al.  Optical fiber-coupled variable attenuator using a MARS modulator , 1997, Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components.

[2]  U. Koren,et al.  A wavelength-division multiplexed passive optical network with cost-shared components , 1994, IEEE Photonics Technology Letters.

[3]  David M. Burns,et al.  Nonlinear flexures for stable deflection of an electrostatically actuated micromirror , 1997, Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components.

[4]  Y. Sun,et al.  Performance degradation of all-optical gain-clamped EDFAs due to relaxation-oscillations and spectral-hole burning in amplified WDM networks , 1997, IEEE Photonics Technology Letters.

[5]  Performance and packaging implications of a MEMS based optical modulator for WDM fiber-to-the home systems , 1997, 1997 Proceedings 47th Electronic Components and Technology Conference.

[6]  Dennis S. Greywall,et al.  Phenomenological model for gas-damping of micromechanical structures , 1999 .

[7]  R. W. Tkach,et al.  Fast power transients in WDM optical networks with cascaded EDFAs , 1997 .

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

[9]  T. Chikama,et al.  Low-Noise and Wide-Dynamic-Range Erbium-Doped Fiber Amplifiers with Automatic Level Control for WDM Transmission Systems , 1996 .

[10]  J. A. Walker,et al.  Silicon modulator based on mechanically-active anti-reflection layer with 1 mbit/sec capability for fiber-in-the-loop applications , 1994, IEEE Photonics Technology Letters.