CN105372753B - Few-mode optical fiber with three annular cores - Google Patents

Abstract

The invention relates to a few-mode optical fiber with a three-ring-shaped core; the cross section of the material comprises a pure silicon dioxide matrix and three circular ring cores with slightly larger refractive indexes; the three circular cores have the same size and refractive index distribution, and the adjacent intervals are small; the optical fiber modes in the three annular cores are strongly coupled to form a supermode with larger effective area, so that the nonlinear effect in optical fiber transmission is reduced; the mode field characteristics of the propagating electromagnetic field in the fiber can be varied by varying the size, location and refractive index profile of these rings.

Description

Translated fromChinese

一种三环形芯的少模光纤A few-mode optical fiber with three ring cores

所属技术领域Technical field

本发明涉及一种三环形芯的少模光纤，可应用于光纤光学、光纤通信、光纤无线接入和光学信息处理等领域。The invention relates to a three-ring core few-mode optical fiber, which can be applied to the fields of optical fiber optics, optical fiber communication, optical fiber wireless access, optical information processing and the like.

背景技术Background technique

云计算、大数据和流媒体等所引发的各种业务流量爆炸式增长，世界各个国家相继制定了国家宽带战略，光纤通信容限面临趋近仙农极限的限制，其发展迎来了前所未有的机遇和挑战。近年来，光纤通信业界围绕空分复用(包括芯式复用和模式复用及其结合)这一物理维度对通信网络传输容量实现了突破；空分复用中的多芯光纤和少模光纤研究成为前沿研究热点；相对于单模光纤来说，少模光纤可以通过增大有效面积来减小传输系统中的非线性效应；特别地，环形芯少模光纤可以进一步提高光纤传输特性[MotokiKasahara，Kunimasa Saitoh，Taiji Sakamoto，et al.，Design of Three-Spatial-ModeRing-Core Fiber，Journal of Lightwave Technology，Vol.32，No.7，April 1，2014，1337；Alexander R.May and Michalis N.Zervas，Few-Mode Fibers with Improved ModeSpacing，ECOC 2015，0501]。一种多芯强耦合的超模光纤也得到了大家的关注；多芯超模光纤具有更大的有效面积、高阶模密度大、低模式依赖损耗、低模式耦合和低差分模式群时延[Cen Xia，Neng Bai，Ibrahim Ozdur，et al.，Supermodes for optical transmission，Optics Express，2011，19(17)：16653-16664；Cen Xia，Neng Bai，Rodrigo Amezcua-Correa，et al.，Supermodes in strongly-coupled multi-core fibers，OFC 2013，OTh3K.5]；可见，大有效面积光纤研究具有重要的学术价值和应用价值，前景广阔、意义重大。With the explosive growth of various business traffic caused by cloud computing, big data and streaming media, countries around the world have successively formulated national broadband strategies, and the optical fiber communication capacity is facing the limit of Xiannong's limit, and its development has ushered in an unprecedented Opportunities and Challenges. In recent years, the optical fiber communication industry has achieved breakthroughs in the transmission capacity of communication networks around the physical dimension of space division multiplexing (including core multiplexing and mode multiplexing and their combination); multi-core optical fibers and few-mode Optical fiber research has become a frontier research hotspot; compared with single-mode optical fiber, few-mode optical fiber can reduce the nonlinear effect in the transmission system by increasing the effective area; especially, ring-core few-mode optical fiber can further improve optical fiber transmission characteristics[ Motoki Kasahara, Kunimasa Saitoh, Taiji Sakamoto, et al., Design of Three-Spatial-ModeRing-Core Fiber, Journal of Lightwave Technology, Vol.32, No.7, April 1, 2014, 1337; Alexander R.May and Michalis N . Zervas, Few-Mode Fibers with Improved ModeSpacing, ECOC 2015, 0501]. A multi-core strongly coupled supermode fiber has also attracted everyone's attention; multi-core supermode fiber has larger effective area, high-order mode density, low mode-dependent loss, low mode coupling and low differential mode group delay [Cen Xia, Neng Bai, Ibrahim Ozdur, et al., Supermodes for optical transmission, Optics Express, 2011, 19(17): 16653-16664; Cen Xia, Neng Bai, Rodrigo Amezcua-Correa, et al., Supermodes in strongly- coupled multi-core fibers, OFC 2013, OTh3K.5]; it can be seen that the research on large effective area optical fibers has important academic value and application value, with broad prospects and great significance.

发明内容Contents of the invention

在国家自然科学基金重点项目(编号61431009)、山东省自然科学基金(ZR2011FM015)、“泰山学者”建设工程专项经费、山东省政府公派出国留学项目支持下，综合考虑环形芯少模光纤和多芯超模光纤的优点，本发明提出了一种三环形芯的少模光纤，可增大有效面积，减小光纤传输中的非线性效应，为光纤光学、光纤通信、光纤无线接入和光学信息处理等领域的深入研究提供了重要支持。With the support of the National Natural Science Foundation of China Key Project (No. 61431009), the Shandong Provincial Natural Science Foundation (ZR2011FM015), the special funds for the "Taishan Scholars" construction project, and the Shandong Provincial Government's government-sponsored study abroad project, comprehensively consider the ring-core few-mode fiber and multi-core The advantages of supermode optical fiber, the present invention proposes a few-mode optical fiber with three ring cores, which can increase the effective area and reduce the nonlinear effect in optical fiber transmission. In-depth research in areas such as processing provides important support.

本发明解决其技术问题所采用的技术方案是：The technical solution adopted by the present invention to solve its technical problems is:

本发明提出了一种三环形芯的少模光纤；其横截面包括纯二氧化硅基质和三个折射率稍大的圆环芯；三个圆环芯大小相同、折射率分布相同，而且相邻间隔很小；三个圆环芯内圆半径为R1＝R3＝R5＝5.25E-6m，外圆半径为R2＝R4＝R6＝1.05E-5m；左侧圆环芯中心坐标为(-9.31E-6m，0)，右上侧圆环芯中心坐标为(9.31E-6m，1.075E-5m)，右下侧圆环芯中心坐标为(9.31E-6m，-1.075E-5m)；最外包层直径为1.25E-4m；三个圆环芯的折射率是1.4517，纯二氧化硅的折射率是1.45；三个环形芯中的光纤模式出现强耦合，形成更大有效面积的超模，从而减小光纤传输中的非线性效应；光纤中传输电磁场的模场特性可以通过改变这些圆环尺寸、位置和折射率分布来改变。The present invention proposes a few-mode optical fiber with three annular cores; its cross-section includes a pure silica matrix and three annular cores with a slightly larger refractive index; the three annular cores have the same size, the same refractive index distribution, and the same The adjacent interval is very small; the inner circle radius of the three ring cores is R1=R3=R5=5.25E-6m, and the outer circle radius is R2=R4=R6=1.05E-5m; the center coordinates of the left ring core are (- 9.31E-6m, 0), the center coordinate of the upper right ring core is (9.31E-6m, 1.075E-5m), and the center coordinate of the lower right ring core is (9.31E-6m, -1.075E-5m); The diameter of the outermost cladding is 1.25E-4m; the refractive index of the three ring cores is 1.4517, and that of pure silica is 1.45; the fiber modes in the three ring cores are strongly coupled to form a superstructure with a larger effective area. mode, thereby reducing the nonlinear effect in fiber transmission; the mode field characteristics of the electromagnetic field transmitted in the fiber can be changed by changing the size, position and refractive index distribution of these rings.

本发明的有益效果是：The beneficial effects of the present invention are:

三个环形芯中的光纤模式出现强耦合，形成更大有效面积的超模，从而减小光纤传输中的非线性效应；使其在光纤光学、光纤通信、光纤无线接入和光学信息处理等领域具有广阔应用前景。The fiber modes in the three ring cores are strongly coupled to form a supermode with a larger effective area, thereby reducing the nonlinear effect in fiber transmission; making it widely used in fiber optics, fiber optic communications, fiber wireless access and optical information processing, etc. The field has broad application prospects.

附图说明Description of drawings

图1是本发明一种三环形芯的少模光纤横截面示意图；该光纤整体上是由纯二氧化硅基质和三个折射率稍大的圆环芯组成；三个圆环芯大小相同，相邻间隔很小；三个圆环芯内圆半径为R1＝R3＝R5＝5.25E-6m，外圆半径为R2＝R4＝R6＝1.05E-5m；左侧圆环芯中心坐标为(-9.31E-6m，0)，右上侧圆环芯中心坐标为(9.31E-6m，1.075E-5m)，右下侧圆环芯中心坐标为(9.31E-6m，-1.075E-5m)；最外包层直径为1.25E-4m；三个圆环芯的折射率是1.4517，纯二氧化硅的折射率是1.45。Fig. 1 is a schematic cross-sectional view of a few-mode optical fiber with three annular cores of the present invention; the optical fiber is composed of pure silica matrix and three slightly larger annular cores with a refractive index; the three annular cores have the same size, Adjacent interval is very little; The inner circle radius of three ring cores is R1=R3=R5=5.25E-6m, and the outer circle radius is R2=R4=R6=1.05E-5m; Left side ring core center coordinate is ( -9.31E-6m, 0), the center coordinate of the upper right ring core is (9.31E-6m, 1.075E-5m), and the center coordinate of the lower right ring core is (9.31E-6m, -1.075E-5m) ; The diameter of the outermost cladding is 1.25E-4m; the refractive index of the three ring cores is 1.4517, and the refractive index of pure silica is 1.45.

图2(a)是少模光纤线偏振模式LP01超模a的电场分布，图2(b)是少模光纤线偏振模式LP01超模b的电场分布；两者是简并模式，有效折射率为1.45096。Figure 2(a) is the electric field distribution of the few-mode fiber linear polarization mode LP01 supermode a, and Figure 2(b) is the electric field distribution of the few-mode fiber linear polarization mode LP01 supermode b; both are degenerate modes, and the effective refractive index is 1.45096.

图3(a)是少模光纤线偏振模式LP11超模a的电场分布，图3(b)是少模光纤线偏振模式LP11超模b的电场分布，图3(c)是少模光纤线偏振模式LP11超模c的电场分布，图3(d)是少模光纤线偏振模式LP11超模d的电场分布；上述四者是简并模式，有效折射率为1.45061；图2和图3中入射光波长为1545nm，等位线表征入射光电场的强弱，密度越大，电场越强；箭头是电场方向。Figure 3(a) is the electric field distribution of the few-mode fiber linear polarization mode LP11 supermode a, Figure 3(b) is the electric field distribution of the few-mode fiber linear polarization mode LP11 supermode b, and Figure 3(c) is the few-mode fiber line The electric field distribution of polarization mode LP11 supermode c, Fig. 3(d) is the electric field distribution of few-mode fiber linear polarization mode LP11 supermode d; the above four are degenerate modes, and the effective refractive index is 1.45061; Fig. 2 and Fig. 3 The incident light wavelength is 1545nm, and the equipotential line represents the strength of the incident light field. The greater the density, the stronger the electric field; the arrow is the direction of the electric field.

具体实施方式Detailed ways

下面结合附图和实施对本发明进一步说明。The present invention will be further described below in conjunction with the accompanying drawings and implementation.

图1是本发明一种三环形芯的少模光纤横截面示意图。该光纤整体上是由纯二氧化硅基质和三个折射率稍大的圆环芯组成。三个圆环芯大小相同，内圆半径为R1＝R3＝R5＝5.25E-6m，外圆半径为R2＝R4＝R6＝1.05E-5m；左侧圆环芯中心坐标为(-9.31E-6m，0)，右上侧圆环芯中心坐标为(9.31E-6m，1.075E-5m)，右下侧圆环芯中心坐标为(9.31E-6m，-1.075E-5m)；最外包层直径为1.25E-4m；三个圆环芯的折射率是1.4517，纯二氧化硅的折射率是1.45；光纤中传输电磁场的模场特性可以通过改变这些圆环尺寸、位置和折射率分布来改变。Fig. 1 is a schematic cross-sectional view of a tri-annular-core few-mode optical fiber according to the present invention. The optical fiber as a whole is composed of a pure silica matrix and three annular cores with a slightly larger refractive index. The three ring cores have the same size, the inner circle radius is R1=R3=R5=5.25E-6m, the outer circle radius is R2=R4=R6=1.05E-5m; the center coordinate of the left ring core is (-9.31E -6m, 0), the center coordinates of the upper right ring core are (9.31E-6m, 1.075E-5m), and the center coordinates of the lower right ring core are (9.31E-6m, -1.075E-5m); the most outsourcing The diameter of the layer is 1.25E-4m; the refractive index of the three ring cores is 1.4517, and the refractive index of pure silica is 1.45; the mode field characteristics of the electromagnetic field transmitted in the optical fiber can be changed by changing the size, position and refractive index distribution of these rings to change.

图2(a)是少模光纤线偏振模式LP01超模a的电场分布，图2(b)是少模光纤线偏振模式LP01超模b的电场分布；两者是简并模式，有效折射率为1.45096。Figure 2(a) is the electric field distribution of the few-mode fiber linear polarization mode LP01 supermode a, and Figure 2(b) is the electric field distribution of the few-mode fiber linear polarization mode LP01 supermode b; both are degenerate modes, and the effective refractive index is 1.45096.

图3(a)是少模光纤线偏振模式LP11超模a的电场分布，图3(b)是少模光纤线偏振模式LP11超模b的电场分布，图3(c)是少模光纤线偏振模式LP11超模c的电场分布，图3(d)是少模光纤线偏振模式LP11超模d的电场分布；上述四者是简并模式，有效折射率为1.45061；图2和图3中入射光波长为1545nm，等位线表征入射光电场的强弱，密度越大，电场越强；箭头是电场方向。从图2和图3可以看出，三环形芯少模光纤形成超模的有效面积比单芯少模光纤的更大，能更好地减小光纤传输中的非线性效应，为光纤光学、光纤通信、光纤无线接入和光学信息处理等领域提供了重要支持，具有广阔应用前景。Figure 3(a) is the electric field distribution of the few-mode fiber linear polarization mode LP11 supermode a, Figure 3(b) is the electric field distribution of the few-mode fiber linear polarization mode LP11 supermode b, and Figure 3(c) is the few-mode fiber line The electric field distribution of polarization mode LP11 supermode c, Fig. 3(d) is the electric field distribution of few-mode fiber linear polarization mode LP11 supermode d; the above four are degenerate modes, and the effective refractive index is 1.45061; Fig. 2 and Fig. 3 The incident light wavelength is 1545nm, and the equipotential line represents the strength of the incident light field. The greater the density, the stronger the electric field; the arrow is the direction of the electric field. It can be seen from Figure 2 and Figure 3 that the effective area of the supermode formed by the three-ring core few-mode fiber is larger than that of the single-core few-mode fiber, which can better reduce the nonlinear effect in fiber transmission. Optical fiber communication, optical fiber wireless access and optical information processing provide important support and have broad application prospects.

Claims (1)

1. a kind of less fundamental mode optical fibre of three toroidal cores；Its cross section includes pure silicon dioxide matrix and three cylindrical cores；Three annulusThe size of core is identical, index distribution is identical；The inner circle radius of three cylindrical cores of the less fundamental mode optical fibre is R1=R3=R5=5.25E-6m, exradius R2=R4=R6=1.05E-5m；Left side cylindrical core centre coordinate is (- 9.31E-6m, 0), rightUpside cylindrical core centre coordinate be (9.31E-6m, 1.075E-5m), lower right side cylindrical core centre coordinate for (9.31E-6m ,-1.075E-5m)；Outermost cladding diameter is 1.25E-4m；The refractive index of three cylindrical cores is 1.4517, the refraction of pure silicon dioxideRate is 1.45.