Abstract

A novel all-fiber flat-top comb filter is proposed based on Sagnac loop interferometer of photonic crystal fiber (PCF). The transmission function of the proposed Sagnac loop filter is expressed theoretically by Jones transmit-matrix. The influences of birefringence of PCF, the lengths of two sections of PCFs and the rotatable angle of polarization controllers on its output spectra are numerically studied. On the basis of theoretical analysis, a wavelength switchable comb filter with flat-top spectral response is realized. This kind of filter can be expected to be used widely in DWDM systems in the future.

© 2011 Optical Society of America