摘要
为考察无需多输入多输出模分复用系统的高速信号传输能力,采用模式选择光子灯笼型模式复用/解复用器构建了2×100 Gb/s双偏振正交相移键控模分复用通信实验系统,系统中用到的少模偏振控制器状态可由LP_(01)和LP_(11b)两个模式信道的信串比参数准确表征。测试了系统误码率与信串比关系,实现两个信道纠后无误码传输的条件为信串比约大于8 dB。当两个信道的信串比分别为14.25 dB和13.81 dB时,与背对背收发系统相比,纠后无误码阈值(10^(-2))的接收光功率代价分别为1.40 dB和4.76 dB。分析了光纤衰减、偏振模色散和模式串扰对高速传输系统的影响,估算了串扰受限系统可支持的少模光纤传输距离约为30 km。
With the continuously increasing demand for optical network bandwidth, high-speed data transmission and large-capacity optical fiber communication technologies are being developed to meet the goal. In Mode Division Multiplexing(MDM) systems, the orthogonal fiber modes are made advantage of carrying different user information in the form of Multiple-input and Multiple-output(MIMO) channels. In the case, both the system spectral efficiency and transmission capacity can be effectively improved by means of MIMO digital signal processing technology. At the same time, to save the system cost and reduce complexity of implementation, more attention is being paid to low-complexity MIMO technology, or even MIMO-free MDM high-speed signal transmission, with applications to short-distance application scenarios such as optical access networks, data centers, and supercomputer interconnections.On the other hand, the mode multiplexer/demultiplexer, as a key component for MDM communication systems, are required for a low mode-dependent loss and mode crosstalk as possible. Their performance parameters can directly affect the system’s bit error rate and the difficulty of algorithm compensation at the receiver. There are several kinds of mode multiplexers, including those of free space type, optical waveguide, fiber coupler, and photonic lantern. Free-space multiplexers have some advantages in mode purity and mode crosstalk, but are limited by complex optical platforms. The multiplexing/demultiplexing scheme based on the waveguide structure has large connection loss with fewmode fibers since the width of the optical waveguides is much smaller than the core radius of the few-mode fibers. The other two multiplexer/demultiplexer are in the form of fiberization and capable of seamless connection to few-mode fiber systems. Among them, the commercially available Mode-selective Photonic Lantern(MSPL) mode multiplexer, as a passive optical device, has the advantages of simple structure, low insertion loss, and multi-port input. The MSPLs are also compatible with other technologies such as wavelength division multiplexing, polarization multiplexing.In the paper, we focus on the high-speed signal transmission capability of MIMO-free Mode Division Multiplexing(MDM) system constructed by the 3-port MSPLs, where each mode channel carries a Dualpolarization Quadrature Phase Shift Keying(DP-QPSK) signal at a bit rate of 100 Gb/s. The state of the Few-mode Polarization Controller(FMPC) used in the experiment can be accurately characterized by the Signal-to-crosstalk Ratios(SXRs) of LP_(01) and LP_(11) mode channels. The relationship between the Bit Error Rate(BER) and the SXRs is measured by adjusting the FMPC. The experimental results show that, no bit error after forward error correction can be achieved when the SXR of each mode channel is more than about 8 dB. When the SXRs of the two channels are respectively 14.25 dB and 13.81 dB, the corresponding degradation of received optical power relative to the back-to-back transceiver system are 1.40 dB and 4.76 dB at the BER threshold of 10^(-2), respectively. The effects of fiber attenuation, polarization mode dispersion and mode crosstalk on the high speed transmission system are analyzed, and the transmission distance limited by crosstalk is estimated to be about 30 km for the few-mode fiber system of interest. Compared with the technologies reported so far, the research in this paper has the highest channel rate, and indicates that the MIMO-free crosstalk limited distance is about 30 km. The 2×2 highspeed MIMO-free mode division multiplexing experiment is carried out before. 100 Gb/s DP-QPSK has higher requirements on the SXR of the channel. Using the same experimental system, appropriately reducing the channel data rate can achieve 3×3 mode division multiplexing system.
作者
唐胜龙
武保剑
严伟
文峰
赵天烽
TANG Shenglong;WU Baojian;YAN Wei;WEN Feng;ZHAO Tianfeng(Key Laboratory of Optical Fiber Sensing and Communications,Ministry of Education,University of Electronic Science and Technology of China,Chengdu 611731,China)
出处
《光子学报》
EI
CAS
CSCD
北大核心
2023年第1期79-87,共9页
Acta Photonica Sinica
基金
国家重点研发计划(Nos.2018YFB1801001,2018YFB1801003)。
关键词
光纤通信
模分复用
信串比
光子灯笼
双偏振正交相移键控
Optical fiber communication
Mode division multiplexing
Signal-to-crosstalk ratio
Photonic lantern
Dual polarization-quadrature phase shift keying
