For the silicon photonic links to meet the target bit error rate (BER), the laser source must output enough optical power to overcome the optical channel loss and limited receiver sensitivity. Combined with poor wall-plug efficiency, this optical power requirement makes the electrical power consumed by the laser source a significant portion of the link energy cost. This article proposes a laser-forwarded coherent link that greatly reduces the required laser optical power by averaging optical path loss between the main and forwarded paths and by improving the receiver sensitivity using a homodyne coherent detector. The link performance analysis reveals that the laser forwarded link improves the laser power budget by ≈6–8 dB compared with a conventional intensity-modulation/direct detection link using typical photonic link components. To demonstrate the laser forwarded link, a microring resonator phase modulator, a balanced detector, and a 3-dB coupler are integrated with CMOS circuits in a GFUS 45-nm SOI process. The transmit driver and the receiver consume 40 and 450 fJ/bit, respectively. Aided by ≈8-dB boost from laser forwarding and the coherent detection gain, the receiver achieves −15.6-dBm optical modulation amplitude sensitivity. The link operates at 10 Gb/s with BER < 10−9 and electrical energy efficiency of 2.3 pJ/bit.

中文翻译：

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使用单片微环谐振器的 45-nm SOI CMOS 激光转发相干收发器

为了使硅光子链路满足目标误码率 (BER)，激光源必须输出足够的光功率以克服光通道损耗和有限的接收器灵敏度。再加上墙插效率低下，这种光功率要求使激光源消耗的电能成为链路能源成本的重要组成部分。本文提出了一种激光转发相干链路，通过平均主路径和转发路径之间的光路损耗并通过使用零差相干检测器提高接收器灵敏度，大大降低了所需的激光光功率。链路性能分析表明，与使用典型光子链路组件的传统强度调制/直接检测链路相比，激光转发链路将激光功率预算提高了≈6-8 dB。为了演示激光前向链路，在 GFUS 45-nm SOI 工艺中将微环谐振器相位调制器、平衡检测器和 3-dB 耦合器与 CMOS 电路集成在一起。发送驱动器和接收器分别消耗 40 和 450 fJ/bit。借助激光转发的≈8-dB 提升和相干检测增益，接收器实现了-15.6-dBm 的光调制幅度灵敏度。该链路以 10 Gb/s 的速度运行，BER < 10−9，电能效率为 2.3 pJ/bit。6-dBm 光调制幅度灵敏度。该链路以 10 Gb/s 的速度运行，BER < 10−9，电能效率为 2.3 pJ/bit。6-dBm 光调制幅度灵敏度。该链路以 10 Gb/s 的速度运行，BER < 10−9，电能效率为 2.3 pJ/bit。