Resonantly enhanced all-optical switching in microfibre Mach-Zehnder interferometers

We propose an all-optical switch based on a microfibre Mach-Zehnder interferometer (MMZI) in which the MMZI is considered with a microfibre loop resonator (MLR) in one arm of it. The authors numerically demonstrate that the enhanced phase shift of the MLR near its resonance wavelengths can be used for constructive/destructive interference and switching functionality of the MMZI. The calculated switching threshold power of the switch is about 2 mW, which can be further reduced by the use of an MLR with more finesse, and the rising and falling times are computed with 21 and 91 ps, respectively. Natural connection to silica single mode fibres, easy configuration and high speed make it as a suitable choice for all-optical signal processing and communications applications.