All-fiber bandwidth-tunable band-rejection filter based on a composite grating induced by CO2 laser pulses.
We propose an all-fiber band-rejection filter with a tunable bandwidth, which is realized by putting a normal long-period fiber grating in series with a rotary long-period fiber grating written in a twisted single-mode fiber by CO(2) laser pulses. Bandwidth tuning is achieved by applying torsion to the composite grating. Our experimental filter shows a bandwidth tuning of approximately 16.3 nm at a rejection level of approximately 15 dB and a polarization-dependent loss lower than approximately 0.9 dB.
Zhu
T
T
Key Lab of Optoelectronic Technology and Systems (Education Ministry of China), Chongqing University, Chongqing, 400044, China. zhutao@cqu.edu.cn
Shi
C H
CH
Rao
Y J
YJ
Shi
L L
LL
Chiang
K S
KS