In the face of the growth trend of high traffic, optical communication network is under great pressure to upgrade, and the existing technology and equipment will not be able to meet the needs of business development. In view of this problem, the key technologies of optical communication in the next ten years are prospectively put forward, covering nine fields: capacity, spectrum, next generation fiber, algorithm, network planning, optical cross connect, new optical access, satellite optical network and optoelectronic integration.

Laser communication will become an important technology means of future satellite communication, especially inter satellite communication, because of its advantages in transmission distance, transmission capacity, confidentiality and anti-interference. However, due to the high speed movement of satellite, the high dynamic satellite laser networking based on laser link will face a series of key technical challenges. This paper summarizes the development status of satellite laser communication technology, introduces the architecture of software-defined satellite laser networks, and analyzes the key technologies for highly dynamic satellite laser networking, and the development direction of satellite laser networking technology is predicted.

Aiming at the problem that there is no suitable construction method of the polarization code for atmospheric turbulence channels at present. Based on the wireless optical communication system, this paper proposes to apply Gaussian partial order to the construction of polar code sequences in atmospheric turbulent channels. The method of constructing polarization codes by Gaussian partial order algorithm is described in this paper. Monte Carlo simulation is used in Matlab to analyze the error rate of 32 sub-channels under σ■■=0.2 turbulent channel and the transmission error probability under different turbulence intensity, and constructed with Gaussian partial order method. The simulation results show that the reliability order of the sub-channels in the weak turbulence channel is basically the same as the polarization code sequence constructed using the Gaussian partial order method, which proves that free space optical communication can use Gaussian partial order method to construct the polarization code sequence in the weak turbulence channel.

In order to research media access control(MAC) protocol in deep space optical communication backbone networks, the structure of deep space optical communication backbone networks is designed, and a flat wireless Mesh structure for deep space optical communication backbone networks is also proposed. Due to the sensitive characteristics of laser communications, this paper designs the node model with multiple interfaces, and the directional media access control(DMAC) protocol is proposed. Compared with non-directional media access control(NDMAC), DMAC protocol can effectively improve the performance of network.

The visible light communication lighting system based on white light emitting diode(LED) has been widely studied. However, the performance of ordinary LED restricts the modulation bandwidth of visible light communication. In order to further improve the modulation bandwidth of LED, micro-size LED can be used. This paper briefly describes the methods to improve the modulation bandwidth of LED, and summarizes the progress in optimizing the performance of micro-size LED in visible light communication in recent years, and points out the research direction of micro-size LED in the future.

In order to realize single mode wireless optical equipment suitable for near ground, a single mode fiber receiving free space optical communication system is designed. A design method of two-level tracking and aperture smoothing is proposed to inhibit the influence of air turbulence and equipment shaking. In this paper, the 900 m field experiment is completed, which reaches the max single mode fiber coupling receiving efficiency of 20% and the received power jitter is less than 6 dB at both ends. The experiment data show that the method of two-level tracking can suppress atmospheric turbulence and shaking. At last, the improvement direction for the future is proposed.

Aiming at the problems of low sensitivity and complex structure of surface plasmon polariton(SPP) sensor at the present stage, a highly sensitive and tunable SPP sensor composed of metal-insulator-metal waveguide and a resonant cavity embedded with silver nanorods is proposed. The optical transmission characteristics and sensing characteristics of the designed sensor are studied by using the finite difference time domain method. The simulation results show that the transmission spectrum will show four or two resonance peaks in the wavelength range of 500~3500 nm when the silver nanorods are introduced into the resonator cavity or not. The refractive index sensitivity of the structure is as high as 2116.72 nm/RIU, the quality factor is 27.51. By filling the cavity with ethanol, the structure can measure the ambient temperature, and the temperature sensitivity can reach 0.98 nm/℃.

In order to solve the problems of traditional seismographs' weak anti-electromagnetic interference ability, narrow frequency response range, large volume and high cost of electromechanical feedback structure, a double-ended Mach-Zehnder (MZ) structure interferometric optical fiber geophone is designed. Use liquid silicone to combine the brass mass with the silicone elastomer to form a one-piece push pull structure, adopt ANSYS software to carry out parametric modeling and lumped parameter finite element analysis of the structure, so as to determine the natural frequency of the structure and when resonance occurs maximum composite amplitude. The signals of different frequency bands are collected by oscilloscope for sensitivity test.The experimental results show that the natural frequency of the geophone when resonance occurs is 106.77 Hz, and the relative error with the experimental value is 1.65%, which verifies the superior potential of the interferometric optical fiber geophone.

In order to use the phase change material Ge2Se2Sb4Te1(GSST) to improve the performance of the optical switch, this paper designs an on-chip multifunctional controllable infrared optical switch based on the phase change material. The device is filled with a phase change material GSST in an ultra-compact silicon waveguide with an etched nanohole array structure. By adjusting the characteristics of the phase change material, it can realize the control of signal light in different polarization states in the infrared band. The simulation results show that the light with a wavelength of 1750~1880 nm, when the GSST material is crystalline, the polarization extinction ratio of TE mode light is as high as -30.7 dB, while the insertion loss of TM mode light is only -5.39 dB, when GSST phase change material in an amorphous state, the insertion loss of both can be ignored.

In order to realize the packet switched network compatible with the existing circuit switched network, the pseudo wire simulation technology is used to shield the difference between the circuit switching network and the packet switching network, and the seamless connection between the two networks is realized. Based on the pseudo wire simulation and E1 pseudo wire simulation protocol, This paper introduces the implementation method of an adaptive clock in pseudo wire simulation and the solution to the asymmetry of bidirectional delay. The experimental data show that this method can control bidirectional delay in E1 pseudo wire simulation within 2 μs.

In order to solve the high cost problem caused by high peak to average power ratio(PAPR) which need the high-resolution digital-to-analog converter/analog-to-digital converter(DAC/ADC) in the intensity modulation and directly detection (IMDD)-based universal multi-carrier(IMDD-UFMC) modulation optical transmission system, a non-uniform quantization scheme based on self-organizing mapping(SOM) neural network is proposed in this paper. The scheme minimizes the quantization error by unsupervised learning through a competitive mechanism to realize the non-uniform quantization with the minimum quantization noise, so as to improve the system performance of IMDD-UFMC. In this way, the low-bit resolution but efficiency DAC can be employed in the IMDD-UFMC system. The simulation results show that compared to the uniform quantization scheme, the non-uniform quantization scheme of SOM can reduce 1 bit resolution in the case of the same system performance, in some cases, it can improve the receiving sensitivity of at least 1.7dB.

In order to reduce the over standard fluctuation of optical fiber parameters and improve the effective drawing length, based on OVD manufacturing technology, the core rod and handle connection process and its relationship with optical fiber parameters near the interface are studied. The connection process of core rod and handle using automatic computer numerical control lathe is described. The influence of connection process on optical fiber performance is analyzed theoretically, and comparative experiments were carried out by drawing the core rods with different connection process. The experimental results show that the one-time coincidence rate of the core rod runout value can be increased from 90% to more than 98%. It is established that the extruasion dgree DD0 which is beneficial to reduce the fluctuation of mode field diameter is 1.2, and the hydrogen oxygen ratio 2∶1.1 is the optimal connection parameter for the optical fiber water peak performance without interface bubbles.