US 12,265,260 B2
Optical fiber signal mode conversion apparatus and conversion method, and optical fiber transmission system
Hanchen Yu, Shenzhen (CN); and Xiang Yin, Shenzhen (CN)
Assigned to Huawei Technologies Co., Ltd., Shenzhen (CN)
Filed by HUAWEI TECHNOLOGIES CO., LTD., Guangdong (CN)
Filed on Jun. 30, 2022, as Appl. No. 17/855,110.
Application 17/855,110 is a continuation of application No. PCT/CN2020/141092, filed on Dec. 29, 2020.
Claims priority of application No. 201911405404.8 (CN), filed on Dec. 30, 2019.
Prior Publication US 2022/0334311 A1, Oct. 20, 2022
Int. Cl. G02B 6/14 (2006.01); G02B 6/12 (2006.01); G02B 6/28 (2006.01)
CPC G02B 6/14 (2013.01) [G02B 6/28 (2013.01); G02B 2006/12152 (2013.01); G02B 6/2821 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An optical fiber signal mode conversion apparatus, comprising:
a non-single-mode optical fiber, wherein the non-single-mode optical fiber comprises a first mode channel and a second mode channel, the first mode channel is configured to transmit a signal in a first mode, and the second mode channel is configured to transmit a signal in a second mode; and
a single-mode optical fiber, configured to form, with the non-single-mode optical fiber, a first coupling region and a second coupling region along a signal transmission direction in the non-single-mode optical fiber, wherein:
an effective refractive index of a fundamental mode signal of the single-mode optical fiber in the first coupling region is equal to an effective refractive index of the signal in the first mode, and the signal in the first mode is coupled to a fundamental mode channel of the single-mode optical fiber; and
an effective refractive index of the fundamental mode signal of the single-mode optical fiber in the second coupling region is equal to an effective refractive index of the signal in the second mode, and the fundamental mode signal of the single-mode optical fiber is coupled to the second mode channel; and
a length of the first coupling region is equal to a coupling length for the signal in the first mode, wherein the coupling length is a shortest length when optical signal energy is completely transferred from the non-single-mode optical fiber to the single-mode optical fiber for a first time.