CN212933176U

CN212933176U - Optical isolator

Info

Publication number: CN212933176U
Application number: CN202022148403.4U
Authority: CN
Inventors: 邹支农
Original assignee: Jiangxi Tfc Optical Communication Co ltd
Current assignee: Jiangxi Tfc Optical Communication Co ltd
Priority date: 2020-09-27
Filing date: 2020-09-27
Publication date: 2021-04-09
Anticipated expiration: 2030-09-27

Abstract

The utility model discloses an optical isolator, include: the polarization analyzer comprises a first polarizer, a Faraday rotator, a second polarizer and a quarter-wave plate, wherein the first polarizer, the Faraday rotator, the second polarizer and the quarter-wave plate are sequentially arranged along the direction of an optical path; and the transmission direction of the second polaroid and the fast axis and the slow axis of the quarter-wave plate form an angle of 45 degrees. The utility model provides an optical isolator, on the basis of the existing single-stage optical isolator, the effect of the double-stage optical isolator can be achieved only by adding a quarter wave plate, and the isolation effect can be greatly improved; and the cost of the quarter-wave plate is low, so that the optical isolator can be increased at low cost, and an excellent isolation effect is obtained.

Description

Optical isolator

Technical Field

The utility model belongs to the technical field of the isolator, concretely relates to optical isolator.

Background

An optical isolator is a passive device that allows light to pass in one direction but prevents it from passing in the opposite direction, and serves to prevent backward propagating light in the optical path due to various causes from adversely affecting the light source and the optical path system, for example, the optical isolator can protect the laser from being damaged by the reflected laser light.

Optical isolators are widely used in various systems, such as fiber lasers, erbium-doped fiber amplifiers, multistage laser amplifiers, optical parametric oscillators, ring lasers, injection-type lasers, permanent magnet-type optical rotators, and the like; the method can also be applied to other fields related to lasers, such as Bose Einstein condensation system, civil and military atomic clock system, laser etching and other high-technology fields. However, the existing optical isolator has poor isolation effect.

Therefore, in view of the above technical problems, it is necessary to provide a new optical isolator.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an optical isolator that simple structure, isolation effect are excellent to solve the problem among the prior art.

In order to achieve the above object, the present invention provides the following technical solutions:

an optical isolator comprising: the polarization analyzer comprises a first polarizer, a Faraday rotator, a second polarizer and a quarter-wave plate, wherein the first polarizer, the Faraday rotator, the second polarizer and the quarter-wave plate are sequentially arranged along the direction of an optical path;

and the transmission direction of the second polaroid and the fast axis and the slow axis of the quarter-wave plate form an angle of 45 degrees.

Further, the optical isolator further comprises a magnet for applying a magnetic field to the faraday rotator, the magnet being capable of forming a magnetic field parallel to the optical path direction.

Further, the magnetic field formed by the magnet is set so that the polarization direction of light passing through the faraday rotator is the same as the transmission direction of the second polarizing plate.

Further, the first polarizing plate and the second polarizing plate are parallel to each other, and a transmission direction of the first polarizing plate and a transmission direction of the second polarizing plate form an angle of 45 °.

The utility model discloses beneficial effect:

the utility model provides an optical isolator, on the basis of the existing single-stage optical isolator, the effect of the double-stage optical isolator can be achieved only by adding a quarter wave plate, and the isolation effect can be greatly improved; and the cost of the quarter-wave plate is low, so that the optical isolator can be increased at low cost, and an excellent isolation effect is obtained.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic perspective view of a preferred embodiment of the present application;

fig. 2 is a schematic diagram of an application scenario of the embodiment shown in fig. 1.

Description of reference numerals: 1-a first polarizer; 2-faraday rotator; 3-a second polarizer; 4-a quarter wave plate; 5-optical fiber.

Detailed Description

The present invention will be described in detail below with reference to embodiments shown in the drawings. However, the present invention is not limited to the embodiments, and the structural, method, or functional changes made by those skilled in the art according to the embodiments are all included in the scope of the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In the illustrated embodiment, directional references, i.e., up, down, left, right, front, rear, etc., are relative to each other and are used to explain the relative structure and movement of the various components in the present application. These representations are appropriate when the components are in the positions shown in the figures. However, if the description of the location of an element changes, it is believed that these representations will change accordingly.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, an optical isolator according to a preferred embodiment of the present invention includes: the polarization analyzer comprises a first polarizer 1 for polarization, a Faraday rotator 2, a second polarizer 3 for polarization analysis and a quarter-wave plate 4 which are arranged in sequence along the direction of an optical path. Wherein the transmission direction of the second polarizer 3 is set at an angle of 45 ° to both the fast axis and the slow axis of the quarter-wave plate 4.

In one embodiment, the first polarizer 1 is fixed to one base on the light incident side, and the exit polarizer is fixed to the other base on the light exit side, so that the first polarizer 1 and the second polarizer 3 are parallel to each other and have their axes coincident. Preferably, the transmission direction of the first polarizer 1 and the transmission direction of the second polarizer 3 are set at an angle of 45 °. In other embodiments, the transmission direction of the first polarizer 1 and the transmission direction of the second polarizer 3 may form other angles.

Specifically, the faraday rotator 2 is disposed between the first polarizing plate 1 and the second polarizing plate 3, and the first polarizing plate 1 and the second polarizing plate 3 are coaxially disposed. The shape of the faraday rotator 2 is not particularly limited, and may be a triangular prism, a quadrangular prism, a cylindrical column, or the like. A magnet for applying a magnetic field thereto is provided on the outer periphery of the faraday rotator 2, and the magnet is capable of forming a magnetic field parallel to the optical path direction. The magnetic field formed by the magnet is set so that the polarization direction of light passing through the faraday rotator 2 is the same as the transmission direction of the second polarizing plate 3.

The following further explains the principle of the optical isolator provided by the present invention:

referring to fig. 2 (solid arrows in fig. 2 indicate the propagation direction and polarization direction of incident light, dashed arrows indicate the propagation direction and polarization direction of reflected light), after passing through the first polarizer 1, the incident light is emitted to the faraday rotator 2 in a certain polarization direction, and the polarization direction of the incident light is rotated to be the same as the transmission direction of the second polarizer 3 under the action of a magnetic field, and then the incident light smoothly passes through the second polarizer 3 and is emitted to the quarter-wave plate 4, and the incident light passes through the quarter-wave plate 4 to become left-handed circularly polarized light, which can pass through the isolator and be coupled into the optical fiber 5 with low loss.

The left-handed circularly polarized light emitted by the quarter-wave plate 4 is reflected by the end face of the optical fiber 5 and then becomes right-handed circularly polarized light (due to half-wave loss), which is the most main reflected light, the right-handed circularly polarized light is changed into linearly polarized light again by the quarter-wave plate 4, and the polarization direction of the linearly polarized light is perpendicular to the transmission direction of the second polarizer 3, so that the linearly polarized light is isolated and cannot pass through the second polarizer 3. If it is considered that reflected light of other polarization states exists in the optical fiber 5, the reflected light can be isolated by the first polarizer 1 (the isolation principle is consistent with that of the existing single-stage optical isolator, and the description is omitted here).

The utility model provides an optical isolator, on the basis of the existing single-stage optical isolator, the effect of the double-stage optical isolator can be achieved only by adding one quarter-wave plate 4, and the isolation effect can be greatly improved; and the quarter-wave plate 4 has low cost, so that the optical isolator can be added at low cost and obtains excellent isolation effect.

It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. An optical isolator, comprising: the polarization analyzer comprises a first polarizer, a Faraday rotator, a second polarizer and a quarter-wave plate, wherein the first polarizer, the Faraday rotator, the second polarizer and the quarter-wave plate are sequentially arranged along the direction of an optical path;

2. The optical isolator of claim 1 further comprising a magnet for applying a magnetic field to the faraday rotator, the magnet capable of creating a magnetic field parallel to the optical path.

3. The optical isolator according to claim 2, wherein the magnetic field formed by the magnet is set so that the polarization direction of light passing through the faraday rotator is the same as the transmission direction of the second polarizing plate.

4. The optical isolator of claim 3, wherein the first and second polarizers are parallel to each other, and wherein the direction of transmission of the first polarizer and the direction of transmission of the second polarizer form an angle of 45 °.