Wavelength switchable flat-top all-fiber comb filter based on a double-loop Mach-Zehnder interferometer.
A wavelength switchable all-fiber comb filter with flat-top spectral response based on a double-loop Mach-Zehnder (M-Z) interferometer is proposed and demonstrated. The proposed flat-top filter consists of a rotatable polarizer and a double-loop M-Z interferometer composed of two fiber couplers with a polarization controller (PC) in the first loop. In the theoretical analysis, when the second coupler of the M-Z interferometer is a non-3dB one, with proper settings of the polarization state of the input light and the PC, the wavelength switchable comb filter with flat-top passband can be obtained. Theoretical prediction was verified by experimental demonstration. The measured 1 dB bandwidth was 0.51 nm with a channel spacing of 0.98 nm, indicating that the flat-top passband of 1 dB bandwidth extends to about 50% of the comb spacing.
Luo
Ai-Ping
AP
Laboratory of Photonic Information Technology, School of information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, Guangdong 510006, PR China.
Luo
Zhi-Chao
ZC
Xu
Wen-Cheng
WC
Cui
Hu
H
D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D005374:Filtration / Q000295:instrumentation*; D007368:Interferometry / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*