用于平衡探测器的5Gb/s前置放大器设计

A Design of 5Gb/s Preamplifier for Balanced Detector

摘要:

相干光通信的平衡探测器采用双端差分结构, 能够有效地提高光通信灵敏度。前置放大器作为光接收器的前端, 其性能高低直接影响到整个光接收系统的工作性能, 是光接收器的重要组成部分。文章采用SMIC 0.13μm CMOS工艺, 实现了一种应用于5Gb/s平衡探测器的接收机前置放大器。前置放大器采用具有低输入阻抗特点的RGC结构作输入级, 同时输出级采用两级结构, 在保证带宽的前提下能够提供足够大的电流驱动50Ω负载。仿真结果表明, 该前置放大器带宽能达到要求的5.12GHz, 灵敏度达到-18.4dBm, 眼图张开度良好, 能够满足系统对噪声抑制的要求。

Abstract:

Balanced detectors for the coherent optical communication which utilizes differential structure, can improve the sensitivity of optical communication effectively. As the front end of optical receiver, the preamplifier is the main part and its performance can decide the property of the whole receiver system directly. In this article, SMIC 0.13μm CMOS technology was employed to implement a 5Gb/s optical receiver preamplifier applied for balanced detector. The proposed preamplifier adopts RGC input structure of low input impedance. In order to get enough bandwidth and big current driving 50Ω load, the output buffer stage is realized by two-stage structure. The simulation results show that the bandwidth can be up to 5.12GHz and the sensitivity is -18.4dBm. Meanwhile, the eye diagram is clear and can satisfy the need of noise suppression.