短距离弱耦合空分复用实时光传输技术

短距离光纤传输系统的容量扩展受到越来越广泛的关注。空分复用光传输技术提供了纤芯和模式两个新维度,可以大大提升单根光纤的传输容量。然而空间信道间的串扰严重限制了空分复用技术的实用化。首先研究了弱耦合空分复用光纤,通过在纤芯引入环形折射率微扰的方法实现了模式之间的有效分离;其次,提出了一种可以处理非圆对称简并模式的全光纤复用/解复用器件以及低插损、低串扰扇入扇出器;在此基础上,使用低成本商用强度调制直接检测光模块,实现了短距离弱耦合模分复用及多芯少模复用实时光传输;最后对空分复用实时光传输技术进行了展望。

Weakly-coupled real-time SDM technology for short-reach optical transmission

The capacity upgrade of short-reach optical fiber transmission has received more and more attention.Spatial division multiplexing provides two new dimensions of fiber core and mode, which can greatly increase the transmission capacity of a single fiber.However, the crosstalk between spatial channels severely limits the practical application of space division multiplexing technology.To address the problem, a weakly-coupled space-division multiplexing fiber was firstly designed, in which perturbed rings were introduced in the core to increase the effective refractive index difference between LP modes.Secondly, an all-fiber mode multiplexer/demultiplexer that could handle non-circularly symmetric degenerate LP modes was proposed, as well as a low insertion loss and low crosstalk fan-in and fan-out devices.Based on the proposed fiber and devices, the low-cost intensity modulation and direct detection were used to implement the short-reach weakly-coupled mode-division-multiplexing and multi-core and few-mode real-time transmission.Finally, the prospective of space-division multiplexing real-time optical transmission technology was discussed.