Four-port optical circulator with symmetric structure

Abstract

The invention discloses a four-port optical circulator with a symmetric structure. The optical circulator is sequentially provided with a dual optical fiber collimating device, a beam splitting / combining element, a polarization conversion subassembly, a light path transformation subassembly, a polarization conversion subassembly, a beam splitting / combining element and a dual optical fiber collimating device along the axial direction of the whole device, wherein the beam splitting / combining element adopts a parallelogram birefringent crystal structure, and moreover, the left inclined surface and the right inclined surface in the crystal structure are both toward the light transmission direction; the light path conversion subassembly comprises a wedge plate pair and a roof prism, wherein the wedge plate pair is formed by combining two wedge plates which are matched with each other at angles; and the optical axes of the two wedge plates are mutually orthogonal. With the adoption of the four-port optical circulator with the symmetric structure provided by the invention, a symmetric light path can be enabled to be formed in the beam splitting / combining element, and the input and output of the optical circulator can be kept on the axis of the whole equipment, thus, the production and assembly can be conveniently carried out; and benefits are brought to debug the light path and package devices.

Description

technical field [0001] The invention belongs to the technical field of light guide components, and more specifically relates to a four-port optical circulator with a symmetrical structure. 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 tran...

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 circulators still have the following defects or deficiencies: First, the current four-port optical circulators usually A birefringent crystal with a cuboid structure is 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 two beams The optical path of the light in the direction of the main axis of the optical circulator is symmetrical, which correspondingly causes the problem that it is difficult to assemble the optical circulator accurately; secondly, the current four-port optical circulator adopts a cuboid birefringent crystal structure with two optical axes orthogonal to each other. Together with the roof prisms arranged on both sides of the cube crystal as the optical path conversion component, in order to achieve the purpose of optical path control and circular transmission, but the optical path converter with this structure often has complex components and high device cost, especially not conducive to optical path debugging and device package

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