Coupled U-shaped cantilever actuators for 1×4 and 2×2 optical fibre switches

Thermally-driven coupled cantilever actuators for multistable switching in micromechanical 1 × 4 and 2 × 2 optical fibre switches are presented. The coupled U-shaped cantilevers for a lateral movement of fibres eliminate angular displacements. The clamp mechanism for multistable switching makes use of an H-shaped buckling platform and results in latching type switches. The coupled U-shaped actuators are thermally-driven with a power of approximately 350 mW and 1 W for the 2 × 2 switch and the two outer fibres of the 1 × 4 switch, respectively. The power needed for the two inner fibres of the 1 × 4 switch corresponds to the 2 × 2 switch behaviour. A switching time of 300 ms has been achieved so far. The first fabricated micromechanical 2 × 2 and 1 × 4 switches show good optical properties with insertion losses less than or equal to 1 dB and a crosstalk less than -60 dB. The fabrication is based on full-wafer micromachining using V-grooves both for fibre alignment and for cantilever formation in {100} silicon.