Multimode interference photonic switches (MIPS)

The switching characteristics of multimode interference photonic switches (MIPS) are analyzed by wide-angle finite difference beam propagation method (FD-BPM). As a result, it is found that the MIPS with a multimode interference (MMI) length of 599 4m can switch the output light polarization insensitively with a crosstalk of less than -20 dB for a wavelength range of 70 nm. These analyses show that the MIPS can also have a 3-dB coupler function. Experimentally, an InGaAsP/InP 1 x 2 MIPS with a thicker InP cladding layer was fabricated and exhibited switching operation with crosstalks of -8 dB and -10 dB at 0 and 20 mA current injections, respectively. For a 2 x 2 MIPS with a thinner InP cladding layer, better switching characteristics with a crosstalk of - 13 dB and an extinction ratio of 17 dB were realized.