Photonic Bandgap Fiber Filter Design Based on Nonproximity Resonant Coupling Mechanism

The possibility of designing compact ultranarrow bandpass filters based on the phenomenon of nonproximity resonant tunneling in multicore photonic bandgap fibers is proposed and numerically demonstrated in this investigation by making use of versatile algorithms based on the finite-element method. The proposed multifunctional assembly exhibits bandpass transmission characteristics at four closed spaced wavelengths with a 3-dB bandwidth of about 1.2 nm and an insertion loss of about 0.8dB. The isolation level between neighbor channels, ranging from 12dB up to 15 dB, could be achieved at optical frequencies. The overall device performance offers some promising propagation characteristics for various all-fiber narrow bandpass filters.