Realization of all-optical multiplexer–demultiplexer in mid-IR wavelengths using triple-core photonic quasi-crystal fiber

We report a wide bandwidth and low crosstalk Ge11.5As24Se64.5 triple-core photonic quasi-crystal fiber (TPQF) for the multiplexing–demultiplexing (MUX–DEMUX) operation in mid-IR region. In this numerical investigation, we explore the various MUX–DEMUX parameters such as coupling length, coupling length ratio, separation length, crosstalk and bandwidth. Further, the proposed TPQF based MUX–DEMUX exhibits high bandwidth of 263, 252, 214, 129 and 134 nm for low crosstalk of -36.47, -34, -31, -30 and -31.3 dB at the wavelengths of 2, 2.3, 2.9, 3.5 and 4μm, respectively. The proposed MUX–DEMUX characteristics are realized first time in TPQF at mid-IR wavelengths. Besides, the bandwidth is improved as 310, 292, 286, 148 and 164 nm for the very low crosstalk level of -45.8, -44, -42.3, -42.35 and -49.93 dB for the separation lengths of 5.5, 6.1, 6.6 and 7.4 mm wavelengths of 2/4-μm, 2.3/4-μm 2.9/4-μm and 3.5/4-μm, respectively, when phase of core 1 is about 1.2π. Thus, the proposed TPQF-based MUX–DEMUX is a suitable candidate for the development of mid-IR photonic devices such as wavelength division multiplexing (WDM) couplers and power splitters.