Multiple port closed-circuit light circulator

Abstract

The invention is a multi-port closed-circuit optical circulator, which is composed of an input / output collimator, a Faraday rotator, and a polarized beam splitting / combining device, and is characterized in that the basic unit of the polarized beam splitting / combining device It consists of a first nano-grating sheet (7) and a second nano-grating sheet (8), which are respectively placed on both sides of the Faraday rotator, and the relative angle between the grid bars of the two nano-grating sheets is 45 degrees. The input / output collimator is placed on both sides of the Faraday rotator and the polarized beam splitting / combining device. The input light is split through the first nano-grating sheet (7), and a total reflection mirror is placed in the optical path of the reflected light and the transmitted light, and is placed on both sides of the two nano-grating sheets and the Faraday rotator. Nano-metal gratings are used to replace traditional birefringent crystals to realize beam splitting / combining functions; by placing the grating directions of two nano-gratings at an angle of 45 degrees, two half-wave plates can be omitted in the optical path. Therefore, the cost of the device is reduced; the manufacturing process of the device is simple, and any port expansion design can be carried out according to the needs, and the closed loop function of the optical path can be truly realized.

Description

technical field [0001] The invention relates to a multi-port closed-circuit optical circulator, which is used for controlling the path of optical signals in an optical communication system, and belongs to the technical field of passive optical devices. Background technique [0002] The optical circulator is a non-reciprocal optical passive device with multi-port input and output. It has the characteristics of forward transmission and conduction of optical signals along a fixed port sequence, and the prohibition of reverse transmission. Because it has the functions of optical ring line, optical coupling and optical isolation at the same time, and has low insertion loss and good isolation performance, it can be widely used in optical amplifiers, DWDM, optical time domain reflectometers and two-way communication systems in optical communications. Optical circulators play an important role in fiber bragg grating (FBG)-based applications in wavelength division multiplexing networ...

AI Technical Summary

Problems solved by technology

[0004] Current optical circulators usually use birefringent crystals as polarization beam splitters / combiners and optical path controllers, which have disadvantages such as complex manufacturing process, many components required, and large device volume, and most optical circulators cannot realize Closed loop function, for example: for an n-port circulator, the light beam input to port 1 can be output from port 2, and the light input from port 2 can be output from port 3 until port (n-1) is input to port n and output, but The output beam cannot be obtained from the input beam of port n, and the closed-circuit optical circulator allows the input beam of input port n to be output from port 1, thereby realizing the complete circulation function of the beam

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