Space light bridge with precise grating adjustment

Abstract

The invention discloses a space light bridge with precise grating adjustment. The 90-degree and 180-degree space light bridges with two-channel input and of two-channel output consist of four blocks of gratings with same period and structure and a precise displacement controller; the 90-degree space light bridge with two-channel input and four-channel output consists of four blocks of grating with same period and structure, a precise displacement controller and two polarizing beam splitters. The space light bridge has the characteristics of small volume, light weight and continuous and adjustable phase. The two multiplied by two 90-degree space light bridge also has the advantage of no need of wasting 50 percent of energy. The space light bridge is applicable to coherent detectors and communication systems which are bridged in space.

Description

technical field [0001] The invention relates to coherent laser communication, which is a precision grating-adjusted space optical bridge, which is used in the coherent detection optical receiver for spatial composite laser signal beams and local oscillator laser beams, and generates 90-degree, 180-degree phase Shift output to achieve 2×2 90-degree, 2×2 180-degree, and 2×4 90-degree bridging in space. Background technique [0002] In the coherent optical communication system, the optical bridge is one of the most important key devices to link the signal laser and the local oscillator laser and generate the required phase shift. According to the type of phase shift, the optical bridge is divided into 90° , 180° two types, of which 180° phase shift bridge is used for balanced PLL receiver, and 90° phase shift bridge is used for Costas PLL receiver. According to the number of input-output ports, it is divided into different types such as 2×2 and 2×4. In free-space optical brid...

AI Technical Summary

Problems solved by technology

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. Document 2: R. Garreis, C. Zeiss, "90°optical hybrid for coherent receivers," Proc. SPIE, Vol.1522, pp.210-219, 1991.) Proposed a 2×2 spatial optical bridge scheme that can achieve 90-degree and 180-degree phase shifts by using wave plates combined with the principle of polarized light interference. Literature [2] proposed a 2×4 90-degree phase shift on this basis. However, this solution has the disadvantages that the entire optical system needs to ensure the strict equal optical path transmission of the beam, there are too many related components, it is not easy to integrate, and it cannot be used in a wide spectrum.

The 2×2 90-degree spatial optical bridge in the literature [1] also has the disadvantage of losing 50% of energy

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 crystals, another 2×490-degree space optical bridge solution is proposed. Although it solves the shortcomings of the prior art [1] and [2], there are too many related components and it is not easy to integrate, but this technical solution is beneficial to The cutting precision of the crystal is high, and the angle relationship between the crystal optical axis, the main section of the crystal and the input linearly polarized light must be strictly guaranteed, otherwise the coherent receiving efficiency will be affected

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