CN-224203532-U - Magneto-optical depolarizer

Abstract

The utility model discloses a magneto-optical depolarizer, which comprises a laser source and a magneto-optical crystal arranged along the light propagation direction, wherein the magneto-optical crystal is arranged above a magnetic guide rail, the magnetic guide rail generates a magnetic field parallel to the light propagation direction, and the magnetic field strength sequentially decreases along the vertical light propagation direction, so that the rotation angles of different areas of micro-sections on an optical surface are different when passing through the magneto-optical crystal to realize depolarization. The utility model realizes depolarization by using more than one non-uniform magnetic field with linear change in one-dimensional direction, so that the rotation angles of different areas of each micro-section on the optical surface are different.

Inventors

• WU LI
• ZHENG BAOZHONG
• XU YUNBING
• CHEN LIXUN
• ZHAO WULI
• LI YANG

Assignees

• 福州高意通讯有限公司

Dates

Publication Date

20260505

Application Date

20250603

Claims (9)

1. 1. A magneto-optical depolarizer is characterized by comprising a laser source and a magneto-optical crystal arranged along a light propagation direction, wherein the magneto-optical crystal is arranged above a magnetic guide rail, the magnetic guide rail generates a magnetic field parallel to the light propagation direction, and the magnetic field strength sequentially decreases along a perpendicular light propagation direction, so that the rotation angles of different areas of micro-sections on an optical surface are different when passing through the magneto-optical crystal to realize depolarization.
2. 2. A magneto-optical depolarizer according to claim 1, wherein the magnetic guide rail is composed of NdFeB and an iron plate, a coil is arranged on the magnetic guide rail, and the magnetic guide rail generates a magnetic field when the coil is electrified, so that the magneto-optical depolarizer realizes depolarization.
3. 3. A magneto-optical depolarizer according to claim 1, wherein the surface of the center of the magnetic track has a concentrated flux density of 1.2T and 0.4T 20mm from the surface of the center of the magnetic track.
4. 4. A magneto-optical depolarizer according to claim 1, wherein the magneto-optical crystal is a TGG crystal or a magneto-optical Faraday rotation Garnet crystal.
5. 5. A magneto-optical depolarizer as claimed in claim 1, wherein the laser source is a monochromatic laser or a broadband laser.
6. 6. A magneto-optical depolarizer as defined in claim 1, wherein the magnetic track has two or more different magnetic fields in the direction of light propagation, the different magnetic fields having different magnetic field strengths at the same level.
7. 7. A magneto-optical depolarizer as defined in claim 1, wherein the number of magneto-optical crystals is two, the two magneto-optical crystals are arranged at intervals, and the magnetic guide rail has different magnetic fields corresponding to each magneto-optical crystal.
8. 8. A magneto-optical depolarizer as set forth in claim 1, wherein the laser light exiting direction of the magneto-optical crystal is provided with a reflecting member having an acute angle with respect to a plane perpendicular to the light propagation direction, and the reflecting member reflects the laser light exiting from the magneto-optical crystal back to the magneto-optical crystal at a prescribed angle.
9. 9. A magneto-optical depolarizer as defined in claim 8, wherein the two or more reflecting members are alternately arranged at an inclination angle to an incident surface and an exit surface of the magneto-optical crystal, respectively, and the reflecting members reflect the laser back and forth so as to pass through the magneto-optical crystal a plurality of times.

Description

Magneto-optical depolarizer Technical Field The utility model relates to the field of optics and lasers, in particular to a magneto-optical depolarizer. Background The most commonly used depolarizer implementation method at present is a double-wedge-angle birefringent crystal structure, which is suitable for multi-wavelength depolarization. For monochromatic linear polarization, some of the linear polarization is formed by combining a 1/4 wave plate with a slow axis of an included angle of 45 degrees or a 1/4 wave plate and a 1/2 wave plate, or a left-handed crystal prism and a right-handed crystal prism. Regarding the depolarizer, U.S. patent US4572608;US4968112;US5028134;US5408357;US5881158;US6522796;US66618521;US6735350;US6760495;US6830339;US6847744;US7072369;US7075644;US7254288;US8331024;US8797533;US9383490;US9599834;US10007041;US10809460;US10935399;US2009/0296066 is a series of patents related to the depolarizer. There is no new conceptual breakthrough in designs of depolarizers over the past decades. Along with the development of optical fiber communication technology, the faraday rotator made of the LPE Garnet faraday magneto-optical rotator crystal in the optical communication band can be produced in large scale, and has the advantages of thin product thickness, low cost and low saturation magnetic field strength, and has been widely used for non-reciprocal passive optical elements in the optical fiber communication technology, such as isolators, circulators, switches and interleavers. Disclosure of Invention The utility model aims to provide a magneto-optical depolarizer. The technical scheme adopted by the utility model is as follows: A magneto-optical depolarizer comprises a laser source and a magneto-optical crystal arranged along a light propagation direction, wherein the magneto-optical crystal is arranged above a magnetic guide rail, the magnetic guide rail generates a magnetic field parallel to the light propagation direction, and the magnetic field intensity sequentially decreases along a perpendicular light propagation direction, so that the rotation angles of different areas of micro-sections on an optical surface are different when passing through the magneto-optical crystal to realize depolarization. Further, the magnetic guide rail consists of NdFeB and an iron plate, a coil is arranged on the magnetic guide rail, when the coil is electrified, the magnetic guide rail generates a magnetic field, and the magneto-optical depolarizer realizes depolarization. Further, the concentrated magnetic flux density of the surface of the center of the magnetic rail reaches 1.2T, and 0.4T is located 20mm away from the surface of the center of the magnetic rail. Further, the magneto-optical crystal is TGG crystal or magneto-optical Faraday rotation Garnet crystal. Further, the laser source is a monochromatic laser or a broadband laser. Further, the magnetic guide rail has more than two different magnetic fields along the light propagation direction, and the magnetic field strengths of the different magnetic fields are different at the same level. Further, the number of the magneto-optical crystals is two, the two magneto-optical crystals are arranged at intervals, and the magnetic guide rail has different magnetic fields corresponding to each magneto-optical crystal. Further, the magnetic field strength gradient directions of the different magneto-optical crystals are different, namely the same plane which belongs to the vertical light propagation direction, but the magnetic field strength gradient directions along the same plane are different. Further, the laser emergent direction of the magneto-optical crystal is provided with a reflecting piece which forms an acute angle with the vertical plane of the light propagation direction, and the reflecting piece reflects the emergent laser of the magneto-optical crystal back to the magneto-optical crystal at a specified angle. Further, more than two reflecting pieces are respectively and alternately arranged on the incident surface and the emergent surface of the magneto-optical crystal at an inclined angle, and the reflecting pieces reflect the laser back and forth so as to pass through the magneto-optical crystal for a plurality of times. According to the technical scheme, the magneto-optical crystal, the magneto-optical glass and the magneto-optical Faraday rotary Garnet crystal are adopted, the optical light transmission surface is placed in an uneven magnetic field, for example, a magnetic field with a one-dimensional direction approximately changing linearly, so that different positions on the optical wave surface in the one-dimensional direction can rotate by different angles, and the total beam section is depolarized. The utility model can also form a vertical uneven magnetic field by linear change of two one-dimensional directions, so that the rotation angles of different areas of each micro-section on the optical surface are different to realize d