Research On All Optical Switching Key Device And Fiber Sensor

With the increasing demand for security,large-capacity,high-speed,and low-latency communication networks,the research of all-optical switching networks and their key diveces have received increasing attention.Narrow linewidth fiber laser is the key device in all optical switching network.Compared to the semiconductor lasers used in the current communication network,the narrow linewidth fiber laser has the advantages of narrow linewidth,good wavelength consistency,small noise,non coupling problems and so on.It will become an important device in the future communication network.At the same time,more attention has been paid to the new optical fiber sensing system with high accuracy,high sensitivity and fast response.Narrow linewidth fiber laser used in optical fiber sensing system will help to reduce the signal noise and improve the sensitivity and stability of the sensing system.At the same time,exploring new optical fiber sensing system is of great significance for the future development of sensing field.This paper introduces the collective research achievement of the scientific research team of our laboratory,the all-optical exchange network demonstration system.On this basis,the narrow linewidth fiber laser is deeply studied,and the characteristics of fiber Bragg grating,Fabry-Perot interferometer and the combination of two fiber Bragg grating narrowband filters are deeply analyzed and applied to the optoelectric oscillator sensing system.The following research results:1.This paper introduces the collective research achievement of the laboratory research team,the all-optical switching demonstration system.In May 2016,the system completed the construction of the first and second generation all-optical switching demonstration system.Compared with the current ROADM technology,the all-optical switching demonstration system in this paper has the advantages of the number of optical fibers not limited by the number of wavelengths,more stability,smaller insertion loss and so on.At the same time,the system has the advantages of nonblocking,large capacity,expansibility,low cost,low energy consumption and so on.At the same time,the signaling system of the system can provide a secure communication network which can not use the back door for network attack.At present,all optical switching network systems are being studied in the direction of miniaturization and practicality in the light of the efforts of other researchers in the laboratory research team.2.The spectral properties of fiber Bragg gratings of Fabry Perot single and dual cavity structures are analyzed by using fiber Bragg grating coupling mode theory.The influence of refractive index modulation depth of fiber grating on its spectral characteristics is simulated and analyzed.On the basis of previous work,we explored the future laser source of all optical switching network and optical fiber sensor.An improved fiber Bragg grating asymmetric dual-cavity structure fiber laser is introduced into the laser to realize the narrow linewidth output of the asymmetric dual-cavity fiber laser.The extinction ratio of the output laser is larger than 55dB,and the 20dB line width is 12kHz,corresponding to the 3dB line width of 0.6KHz.3.The influence of the curvature of the fiber end face on the transmission characteristics and spectral characteristics of the interferometer is studied.A theoretical model is established through Gaussian beam and ray optics theory.The effects of different radian and graded index multimode fibers on the transmission and spectral properties of interferometer are analyzed.The method of making the arc of the optical fiber end face is explored,and the spectral characteristics of the Fabry Perot interferometer with different fiber end faces are experimentally explored.On this basis,the optical fiber alignment and fixing method of the air cavity Fabry Perot fiber interferometer is explored.An air gap Fabry Perot interferometer with an extinction ratio larger than 31dB is fabricated by using this structure.The characteristics of pressure and liquid refractive index of the interferometer are studied.The sensitivity of the pressure sensor is 4.943nm/MPa and the maximum sensitivity of the liquid refractive index is-163.9dB/RIU.4.An optoelectronic oscillator sensing system based on a fiber grating Fabry-Perot narrowband filter is proposed.A fiber grating Fabry-Perot narrowband filter with an air gap is fabricated and the optoelectric oscillator sensor system is built,and the structure enriches the application of optoelectric oscillator sensing system in sensing field.The experimental investigation of the stability and sensing characteristics of the system are conducted.The experimentally measured liquid refractive index sensitivity is 413.8 MHz/0.001RIU and the temperature sensitivity is 2513 MHz/?.