Low-power all-optical gate based on sum frequency mixing in APE waveguides in PPLN

We present an all-optical gate implemented in periodically poled lithium niobate (PPLN) (LiNbO
₃
). Efficient mixing is achieved by using a phase-matched guided-wave interaction. A control wave at 1.537 μm is used to gate a signal at 1.552 μm, where a control power of 185 mW is sufficient to achieve 96% depletion of a low-power signal. A simple switch configuration is described whereby high-contrast low-power all-optical switching can be performed.