Pico-second optical switch using micromachined total internal reflection prism

A pico-second optical switch using micromachined total internal reflection (TIR) prism via phonon-assisted nonlinear two-photon absorption (TPA) is reported in this paper. The incident light is switched to various outputs by changing the refractive index at the interface of the prism using illumination and the prism is finely tuned by a rotational microelectromechanical systems (MEMS) thermal actuator. This switch has multifold advantages over the other techniques. Firstly, the pico-second switching speed is much faster than other mechanical switches. Secondly, the critical angle of TIR for switching is innovative. Thirdly, there is no mechanical instability issue to be addressed. Fourth, the switch is adaptive to silicon substrate variation due to the finely tuning by MEMS actuator. Lastly, the effective volume is small, avoiding the absorption problem of long propagation distance.