Phase-controllable birefringence space light bridge

Abstract

The invention relates to a phase-controllable birefringence space light bridge, which uses a combined birefringence optical flat to achieve light splitting synthesis of two input light beams, wherein a quarter-wave plate performs phase-shift control and is used for space compounding of a laser communication signal light beam and a local oscillation laser beam in a coherent optical communication receiver and outputting four paths of synthesized light beams with a required phase-shift relation so as to achieve 2*4 space light bridging. The quarter-wave plate makes two perpendicular polarized components generate 90-degree phase shift, and the phase difference between the two components can be changed by rotating the optical axis direction so as to compensate phase errors generated by errors of processing, assembling, calibration and the like, thus the phase-controllable birefringence space light bridge has the advantages of simple structure, stable performance and controllable phase. The phase-controllable birefringence space light bridge is applicable in the field of free space laser coherent communication and laser radar.

Description

technical field [0001] The invention relates to coherent laser communication and laser radar, in particular to a phase controllable birefringence space light bridge. The combined birefringent optical plate is used to spatially couple the two input beams and divide them into four synthetic beams for output, realizing a 2×4 spatial optical bridge. The machine is used for spatial composite laser signal beam and local oscillator laser beam, and generates a 90-degree 2×4 spatial optical bridge that can be phase-controlled as required. Background technique [0002] Space-borne laser communication terminals that realize large capacity, high bit rate, small size, light weight and low power consumption are the needs of free space laser communication. Since the receiver sensitivity of coherent optical communication is more than an order of magnitude higher than that of incoherent optical communication, and a variety of modulation methods can be adopted to increase receiver selectivit...

AI Technical Summary

Problems solved by technology

Although in optical fiber communication systems, people use optical fibers and waveguides to develop various optical bridge solutions, these optical bridges suitable for optical fiber communication systems cannot meet the needs of space communication, and do not belong to space optical bridges. In free space laser communication In the system, the received optical signal is not only used to detect communication information but also to extract position information for optical precision tracking. For free space laser communication terminals, the optical bridge must be free space propagation

In free-space optical bridging, prior art [1], [2] (see document 1: WalterR.leeb.Realization of 90°and 180°Hybrids for Optical Frequencies[C]. , Band 37[1983], Heft 5 / 6: 203-206. Literature 2: R.Garreis, C.Zeiss, "90°opticalhybrid for coherent receivers," Proc.SPIE, Vol.1522, pp.210-219, 1991.) proposed a 2×2 spatial optical bridge scheme using a polarizing beam splitter combined with a wave plate, and a non-polarizing beam splitter combined with a wave plate to achieve 90-degree and 180-degree phase shifts. Literature [2] proposed on this basis A 2×4 90-degree phase shift implementation scheme is proposed, but this scheme must make the phases of the two polarization components of the incident beam after passing through the polarizing beam splitter and the non-polarizing beam splitter meet a specific relationship, which is technically difficult to achieve , in addition, the entire optical system needs to ensure the strict equal optical path transmission of the beam, it is difficult to install, there are too many related components, and it is not easy to integrate.

Prior technology [3], [4] (refer to Document 3: Liu Liren, Liu Dean, Yan Aimin, Luan Zhu, Wang Lijuan, Sun Jianfeng, Zhong Xianghong, Electric phase-shift space optical bridge, invention patent, announcement number: 100383572, utility model with the same name Patent announcement number: 200959599; Document 4: Liu Liren, Yan Aimin, Luan Zhu, Liu Dean, Sun Jianfeng, Wang Lijuan, Zhong Xianghong, birefringent free-space optical bridge, invention patent, announcement number: 100383571, utility model patent announcement number of the same name 2899300) comprehensive Using the birefringence effect and electro-optic effect of the crystal, another 2×4 90-degree space optical bridge solution is proposed. Although the disadvantages of the prior art [1] and [2] are too many related components and not easy to integrate, the prior art [3] When performing phase control, it is necessary to apply voltage to each chip and perform voltage adjustment, the process is complicated, and the prior art [4] has the disadvantage of not being able to perform phase control

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