實現於標準金氧半製程之單晶整合光接收器設計

Abstract

本論文設計單晶整合光接收器，在標準金氧半製程裡整合檢光二極體與接收器前端電路。為了補償緩慢基版載子的效應，本論文使用等化器補償檢光二極體的本質響應，並使用負阻抗與主動式電感的技術，其頻寬的提升大於400倍。第一顆晶片使用0.18μm金氧半製程實現一個3.125Gb/s的單晶整合光接收器，在850nm光波長下量測出69 dB□的差動轉阻增益、-8.1dBm的靈敏度與2.5GHz的頻寬，在1.8V供應電壓下消耗36mW的功率。在本論文裡，光纖聚光點大於所設計的檢光二極體面積，加上介電層的的反射折射，故響應率只有原先預期的一半，造成3dB的靈敏度下降。此外，光發射器在亮暗比為6dB時約衰減2.2dB的靈敏度。第二顆晶片以0.13μm金氧半製程實現一個5Gb/s的單晶整合光接收器，其設計目標為600nm-1000nm的光波長可適性。不同波長的光因其入射深度不同，造成不同程度的緩慢增益下降，此接收器因而包含一可調式等化器與一可變增益放大器，確保補償能適當執行。在850nm光波長下量測出60-91 dB□的差動轉阻增益與-1.7dBm的靈敏度，在1.5V供應電壓下消耗112mW的功率。

This thesis presents monolithically integrated optical receivers, consisting of integrated photodiodes and receiver front-end circuits in standard CMOS process. To eliminate the slow substrate carriers effect without sacrificing responsivity, an equalizer is used to compensate the poor intrinsic response of photodiode. Negative impedance and active inductive peaking are adopted to improve the bandwidth further. The compensatory factor is more than 400. The first chip implements a 3.125Gb/s monolithically integrated optical receiver in 0.18μm CMOS process. Measurement result achieves 69dB total differential transimpedance gain, -8.1dBm sensitivity and 2.5GHz optical bandwidth at 850nm light wavelength. This chip dissipates 36mW from a 1.8V supply. In this thesis, because the fiber spot size is larger than the area of photodiode and the reflection is caused by dielectric layers, the responsitivity is only half of the expected one. It therefore causes 3dB sensitivity degradation. Besides, finite extinction ratio of lightwave transmitter impacts the sensitivity. When the extinction is 6dB, the sensitivity degrades about 2.2dB. The second chip implements a 5Gb/s monolithically integrated optical receiver in 0.13μm CMOS technology. This chip is designed for adaptability of 600nm-1000nm light wavelength. Light of different wavelength causes different penetration depth, leading to roll-off in various degree. Therefore, this receiver incorporates a tunable equalizer and a variable gain amplifier for appropriate compensation. Measurement result achieves 60-91dB total differential transimpedance gain and -1.7dBm sensitivity at 850nm light wavelength. This chip dissipates 112mW from a 1.5V supply.