This paper summarized and analyzed the characteristics of PLC, electromagnetic compatibility (EMC) and the characteristics of medium-long wave propagation in the same frequency band, and an effective method was proposed to locate interference by comparing the field strengths of int.

The results show that owing to the increasing of the inversion particles,together with the influence of the temperature on the length of the laser cavity,there is a red shift of the center wavelength with the increasing of the current and temperature.

The conclusion is that the shape of the transmittance curve has been basically holding the line with the center wavelength deviation.

Change of the center wavelength and 3 dB bandwidth is linear with the strain, but the reflectivity decreases when the strain increases.

In the process of experiment investigation on photonic crystal fiber fabricated by ourselves,by increasing the central wavelength of pump pulseλ_0 gradually,the frequency spectrum of pump pulse is widening gradually withλ_0 approaching toλ_D,at the same time,and the intensity of anti-Stokes wave is increasing gradually with the transform-efficiency being enhanced.

Its central wavelength will shift to the short wavelength direction.

Characteristics of superradiance light emitting diode(SLD) are introduced and the effects on the performance of a fiber optic gyro(FOG) such as output power,central wavelength,full width at half maximum(FWHM),degree of polarization(DOP),input current of the SLD are analyzed from the point of view of theory and application,methods to solve these problems are given also.