Compact type optical circulator with four ports

Abstract

The invention discloses a compact type optical circulator with four ports. The optical circulator comprises a first double-fiber collimator, a first beam splitting / combining component, a first polarization converting component, an optical path converting element, a second polarization converting component, a second beam splitting / combining component and a second double-fiber collimator which are sequentially arranged along the integral axial direction of the device, wherein each double-fiber collimator is formed by a thermally expanded core fiber head and a C-lens; each beam splitting / combining component is in a birefringent crystal structure presenting a trapezoid body shape, and a left inclined plane and a right inclined plane which form the same included angle with the lower surface of the crystal structure face the light transmission direction; the optical path converting element presents a wedge angle sheet pair structure which is combined by two wedge angle sheets with matching angles, and the optical axes of the two wedge angle sheets are mutually orthogonal. According to the optical circulator, the integral volume of the device can be reduced effectively, the input and the output of the optical circulator are maintained on a spindle, and therefore production assembly, optical path debugging and device packaging are facilitated.

Description

technical field [0001] The invention belongs to the technical field of light guide elements, and more specifically relates to a compact four-port optical circulator. Background technique [0002] An optical circulator is an important optical passive device in optical fiber communication. Its typical structure has N (N is greater than or equal to 3) ports. See figure 1 , when light is input through one of the ports such as port 1, the light can be output through the other port, namely port 2, almost without loss, and there is almost no light output at other ports; and when light is input through port 2, the light is almost without loss The loss ground is output by port 3, and there is almost no light output from other ports, and so on, so that the optical signal can only be transmitted circularly along a fixed path. As a non-reciprocal device with multi-port input and output, the optical circulator can realize the separation of forward and reverse transmission light, so it i...

AI Technical Summary

Problems solved by technology

[0003] The four-port optical circulator is an extension of the three-port and can provide more optical signal output paths. However, the existing four-port optical circulator still has the following defects or deficiencies: First, in the current four-port optical circulator A birefringent crystal with a cuboid structure is usually used as the beam splitting / combining element, so that the o light will not be deflected after splitting, and the e light will be deflected at a certain angle toward the optical axis of the birefringent crystal itself, so it is impossible to guarantee both The optical path of the light beam in the direction of the main axis of the optical circulator is symmetrical; secondly, the current four-port optical circulator adopts a cuboid birefringent crystal structure with two optical axes orthogonal to each other, and roof prisms respectively arranged on both sides of the cube crystal to Together as an optical path conversion component, in order to achieve the purpose of optical path control and ring transmission, but the optical path converter with this structure often has complex components and high device costs, especially not conducive to optical path debugging and device packaging; third, the existing four-port optical ring The birefringent crystal and polarization conversion components of the liner are usually set beyond the working distance of the dual-fiber collimator, resulting in a relatively large overall volume of the device, which is not conducive to optical path debugging and device packaging

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