Integrated optical switch matrix for single-mode fiber networks

Design analysis and experiments on optical directional coupler switch integration into an LiNbO
3
chip with arrayed fiber pigtails has been made at 1.3 μm wavelength. A limitation for high integration was discussed by taking into account radiation losses at connecting waveguides between switch elements and at the input/output curved waveguide, switching voltage, and crosstalk caused by applied electric field leakage. An optimum designed low-loss 4 × 4 switch matrix with arrayed fiber pigtails at 1.3 μm wavelength has been developed. Its insertion loss was measured to be as low as 6 dB.