Research On Optical Fiber Sensing And Communication System Based On White Light Interferometry

The explosive growth of data traffic puts forward higher requirements on the quality of advanced optical fiber communication networks.It is very important to carry out high precision sensing test on optical waveguide devices in optical fiber communication network.The optical fiber sensing system based on white light interference technology has the spatial resolution of micron level,so it has unique advantages in sensing measurement.At the same time,the security of the communication system cannot be ignored.The secure optical fiber communication technology based on the principle of white light interference not only improves the security of the system,but also realizes the concealment of data transmission.In order to satisfy the high precision sensor and data transmission in optical fiber communication system security requirements,optical fiber sensing and communication system based on white light interferometry are studied in this paper,optical low coherence reflectometry(OLCR)system with high spatial resolution,large dynamic range and high stability at low cost is realized,and secure optical fiber communication scheme in which key and ciphertext are transmitted on the same fiber is proposed.The main content and results are as follows:(1)The principle of white light interferometry is analyzed,and the influence of system noise is discussed.The existing theoretical model of OLCR sensor system based on white light interference technology is analyzed.The system performance parameters such as spatial resolution,dynamic range and test length are introduced.The factors limiting the system performance and the measures to improve the system performance are analyzed theoretically.The principle of optical fiber communication system based on white light interference technology is analyzed,and the security and concealment performance of the system is explained theoretically.(2)Based on the proposed measures to improve the performance of the OLCR system,an enhanced OLCR system with high spatial resolution,large dynamic range and high stability at low cost is realized.Based on spectral shaping technology,the spectral shape of the light source was edited to reduce the self-coherence length of the light source,and the spatial resolution of the OLCR system was improved to 12?m.Based on the polarization self-stabilizing structure,the polarization noise of the OLCR system is removed and the system stability is effectively enhanced.Compared with the traditional structure,the power fluctuation in the electrical domain is reduced by 1.5d B.Based on the optical path difference modulation technology,the interference of baseband noise is avoided.Combined with the frequency domain analysis,the dynamic range of 82d B and the measurement sensitivity of-99d B are achieved in the experimental system.(3)A secure optical fiber communication system in which key and ciphertext are transmitted in the same optical fiber has been proposed.In the key transmission channel,the concealment transmission of the signal is realized based on the principle of white light interference.The simulation analysis and experiment of 1Gb/s and 3Gb/s OOK key signal transmission are carried out for 50km transmission,and the concealment of the key transmission is verified.In the data transmission channel,based on quantum noise stream cipher and coarse and fine modulation,noise-masking number of 2¹⁴-level PAM4-QNSC is realized,and the 50km transmission experiment of 40Gb/s PAM4-QNSC signal is achieved,which verifying the security of data transmission.It is proved that the proposed secure optical fiber secure communication system is effective to realize low-cost high-speed,and highly secure optical transmission.