Beat Frequency Technology And Its Application Of DBR Fiber Laser

In this paper,a measurement system is proposed in the dispersion measurement of optical fiber and optical device.The generation mechanism of the laser beat frequency is studied,and the model of laser beat frequency is established to realize the dispersion measurement of CFBG.The system structure and measuring principle are detailed demonstrated.The measurement results and the referenced values are analyzed and compared,as a result,they are in good consistency.and the comparison of measurement error is not more than 5 Ps.In the case of spectrum analyzer resolution of 2.5kHz,the accuracy can reach 0.1ps,so the experimental system can meet the requirements of the dispersion measurement.In addition,the system is relatively simple and have a high precision,providing a feasible reference in the field of dispersion measurement.In the demodulation technology of fiber laser beat frequency,a simple electrical signal processing method is provided by laser beat frequency demodulation.In addition,the measurement of external physical changes is measured based on DBR laser beat frequency in this paper,which is not affected by the loss of the system and the fluctuation of light source.We succeeded in measuring strain based on laser beat frequency,and the result is good stable.Moreover,owing to the large amount of CFBG delay,a very small change in the wavelength will cause a variation of the resonant cavity change,making the relative change to the cavity length get to 2.25%,which is what the previous sensors could not to get to.As a result,the measurement accuracy is greatly improved.The system not only has a simple structure and low cost,but also make light signal transformed into electrical signal,which provides a convenience for data processing and has a reference value.