TITLE:
Recognition of Bragg Wavelength Disturbed by Time Delay of Fiber Length in Prepositive Tunable Filter
AUTHORS:
Chuan Li, Xiaoyong Chao, Yingna Li, Tao Xie, Zhengang Zhao, Xin Xiong
KEYWORDS:
Optic Fiber; Fiber Length; Bragg Wavelength; Fabry-Perot Filter; Time Delay
JOURNAL NAME:
Optics and Photonics Journal,
Vol.3 No.2B,
July
22,
2013
ABSTRACT:
The wavelength shift in fiber Bragg grating does not
depend directly on the total light levels, losses in the connecting fibers and
couplers, or source power. However, if the tunable Fabry-Perot filter is place
on the end of incident fiber, the detected time delay of modulation light is
occurred due to the unmatch between the scanning time and light transmission
time in the transmission fiber. Consequently, the detected peak wavelength
shifts with the length of transmission fiber. Thus, the peak wavelength shift
effect of Bragg reflective light transmitted in fiber with different fiber
length can be obvious in the demodulator with a prepositive tunable Fabry-Perot
filter. The experiment indicates the shift rates of 0.109 - 0.126 nm/km
increase approximately linearly with the original peak wavelength of 1532.917 - 1560.300
nm at the fiber length of 0 - 6 km. To certify the consistency of
measurement data, the criterion correction is introduced. By using the
differential method of two fiber Bragg gratings with an optical path, the
differential worth is compensated from the disturbance modulated by the time
delay of fiber length.