Peilin Tao

Theoretical and experimental investigation of the mode-spacing of fiber Bragg grating Fabry-Perot cavity

The mode-spacing of the fiber Bragg grating Fabry-Perot (FBG F-P) cavity is calculated by using the effective cavity length which contains the effective length of the FBG. The expression of the effective length, defined by using the phase-time delay, is obtained and simplified as a function of the peak reflectivity at the Bragg wavelength, the band edges, and the first zero-reffectivity wavelength. The effective length is discussed from the energy penetration depth point of view. Three FBG F-P cavities are fabricated in order to validate the effective length approach. The experimental data fits well with the theoretical predictions. The limitation of this method is also pointed out and the improved approach is proposed.

Research on the weak signal detection technique based on optical fiber Mach-Zehnder interferometer

An analysis, based on transfer matrix, is presented of weak signal effects on the mach-zehnder interferometer sensor for detection. The weak signal detector based on Mach-Zehnder optical fiber interferometer is established. Based on wavelet soft-threshold de-noising technology and high-pass filter, a modified demodulation technique is proposed. With the modified demodulation method, experiment results show the systems precision can be improved effectively.

Polarization effects in the sagnac distributed disturbance fiber-optic sensor

An analysis, based on mode coupled equation, is presented of polarization effects in the Sagnac interferometer sensor for distributed detection. The Sagnac distributed disturbance location sensor with polarization controller is established. With a modified demodulation method, experiment results show the systems sensitivity can be improved effectively.

Single-longitudinal-mode DBR fiber laser based on the self-made photosensitive Er-doped fiber

Two fiber Bragg gratings with ~35mm spatial interval are written in the self-made photosensitive Erbium-doped fiber (PEDF) to form a fiber Bragg grating Fabry-Perot (FBG F-P) cavity. A distributed Bragg reflector (DBR) fiber laser is built up based on the FBG F-P cavity. 1.8mW laser output is achieved with 63mW pump power. By calculating the mode-spacing using the effective length of the FBG F-P cavity, the output of the DBR fiber laser is proved to be singlelongitudinal- mode (SLM).

Study on the time delay of uniform fiber Bragg gratings

The time delay of the light reflected from and transmitted through the uniform fiber Bragg grating (FBG) are computed and shown to be equal. The physical meaning of the time delay is discussed based on tunneling effect and energy storage function of the FBG. The energy density of the optical field distributed along the FBG and the total energy stored in the FBG are calculated based on the coupled mode theory (CMT). The time needed for light to form the stable energy density distribution is computed and shown to be equal to the time delay of the FBG.

Optical SSB modulation using fiber Bragg grating and its transmission performance

The single sideband (SSB) modulation format is obtained using the narrowband fiber Bragg grating (NFBG) made by ourselves. Then The SSB modulation format and double sideband (DSB) modulation format transmit over 155 km G.652, respectively. And dispersion is compensated by chirp fiber Bragg grating (CFBG) made by us. The results show that the power penalty of SSB signal is smaller than that of DSB signal when the input power and the bit error rate (BER) are the same; when the BER is E-12, the power penalty of SSB signal is 0.8 dB smaller than that of DSB signal.