Electromagnetic torsion mirrors for self-aligned fiber-optic crossconnectors by silicon micromachining

We report a micromechanical fiber-optic switch (1 cm x 1 cm x 1 mm) based on an electromagnetically operated torsion mirror which is suitable for self-latching operation, The switch is fabricated by silicon micromachining technology, and self-alignment technique is employed to align optical fibers to the mirror, A small mirror of gold finished FeNiCo/polysilicon (150 mu m x 500 mu m) is supported by two beams, and rotated around the axis in the magnetic field induced by an electromagnet. An incident light is redirected by the mirror in a free-space smaller than 1 mm(3). Multimode fibers are used for optical coupling of small loss (-2.5 dB for reflection and -0.83 dB for transmission) at a wavelength 1.55 mu m. Typical switching time is 10-25 ms, and switching contrast is larger than 45 dB. Magnetic torque and optical coupling are theoretically investigated.