US 12,253,746 B2
Small integrated free space circulator
Xi Zheng, Fujian (CN); Guanglong Yu, Fujian (CN); Xu Jia, Fujian (CN); Haifeng Chen, Fujian (CN); and Ce Ren, Fujian (CN)
Assigned to II-VI DELAWARE, INC., Wilmington, DE (US)
Appl. No. 17/309,585
Filed by II-VI Delaware, Inc., Wilmington, DE (US)
PCT Filed Dec. 29, 2018, PCT No. PCT/CN2018/125805
§ 371(c)(1), (2) Date Dec. 14, 2021,
PCT Pub. No. WO2020/113743, PCT Pub. Date Jun. 11, 2020.
Claims priority of application No. 201811497452.X (CN), filed on Dec. 7, 2018.
Prior Publication US 2022/0121045 A1, Apr. 21, 2022
Int. Cl. G02F 1/09 (2006.01)
CPC G02F 1/093 (2013.01) 10 Claims
OG exemplary drawing
 
1. A small integrated free space circulator, comprising a first polarizing beam splitter, a half-wave plate, a Faraday rotating plate, a beam splitter, a quarter-wave plate, and a pair of reflective plates, wherein the first polarizing beam splitter, the half-wave plate, the Faraday rotating plate, and the beam splitter are sequentially arranged, the quarter-wave plate and one of the reflective plates are sequentially attached to a side surface of the first polarizing beam splitter adjacent to the half-wave plate, and the other reflective plate is arranged on a side surface of the beam splitter opposite to the Faraday rotating plate and partially covering the side surface; when the reflective plate is arranged on the side surface of the beam splitter opposite to the Faraday rotating plate, the reflective plate partially covers the side surface of the beam splitter opposite to the Faraday rotating plate; and a polarizing splitting film is provided in the first polarizing beam splitter;
when a signal light is input through an end surface of the first polarizing beam splitter that is away from the half-wave plate, the signal light is split by the polarizing splitting film into a P light and an S light, wherein the P light passes through the polarizing splitting film, then sequentially passes through the half-wave plate and the Faraday rotating plate, and then becomes the S light, which subsequently enters the beam splitter, is guided to the reflective plate and is reflected by the reflective plate back along the original path, then sequentially passes through the Faraday rotating plate and the half-wave plate, enters the first polarizing beam splitter and is reflected by the polarizing splitting film, and is output along a side of the first polarizing beam splitter that is away from the quarter-wave plate; after being reflected by the polarizing splitting film to the side where the quarter-wave plate is arranged and passing through the quarter-wave plate, the S light is reflected by the reflective plate back along the original path, and since the S light has passed through the quarter-wave plate twice, the polarization state of the S light changes and the S light becomes the P light, which subsequently passes through the polarizing splitting film and is output along the side of the first polarizing beam splitter that is away from the quarter-wave plate; and
when the signal light is input through a side of the beam splitter that is away from the Faraday rotating plate, the P light is guided by the beam splitter to sequentially pass through the Faraday rotating plate and the half-wave plate, then enters the first polarizing beam splitter, and then passes through the polarizing splitting film and is output from a side surface of the first polarizing beam splitter that is away from the half-wave plate.