A new method of tuning fiber Bragg grating by electromagnetic force is proposed. The wavelength shift of the fiber Bragg grating is 1.16nm in the range of the current intensity from 0 to 85.5mA. The researches indicate that the system has advantages of simple configuration and high sensitivity.
A technique for temperature compensation in fiber grating vibration sensor is reported. By special design, it causes reversed strain on two FBGs and has temperature effects cancelled. After discussion about the factors affecting the sensitivity and the width of frequency band, it is experimentally proved that the total variation in wavelength difference within temperature of -15 ~ 50°C is nearly 0. When the input vibration frequency is up to 800Hz and the drive power is as low as 2mw, the output waveform is still distortionless.
A novel optical add-drop multiplexer (OADM) based on Mach-Zehnder interferometer and fiber Bragg grating (FBG) is proposed. In the structure, the Mach-Zehnder interferometer acts as an optical switch. The OADM can add/drop one of the multi input channels or pass the channel directly by adjusting the difference of the two arms of the interferometer. The channel isolation is more than 20dB.