一個內含頻寬改善檢光二極體，並使用0.18um互補式金氧半製程設計之2-Gb/s、850nm的光通訊接收器

Abstract

本論文設計單晶整合光接收器，在標準金氧半製程嘗試整合檢光二極體、接收器前端電路與負壓產生器•接收器使用可適性等化器之架構來補償不同逆偏壓下檢光二極體的頻率響應，並使用源級退化級與主動式電感的技術使其頻寬能到達1.4GHz以上•光接收器的設計目標為在不同輸入光強度以及不同檢光二極體頻率響應下，都能達到850nm光波長的可適性。為了接收多模光纖所有的雷射光能量，本次採用的檢光二極體面積為70μm× 70μm。負壓產生器之設計目標在於產生一個-10V的電壓來改善檢光二極體的本質響應•並且能夠因應不同輸入光強度來自動切換時脈頻率，以提升功率效率•因為負壓產生器輸出端與檢光二極體直接相連，故如何抑制負壓的鏈波訊號使其不影響光接收器效能，便是一個設計重點•在此次的整合過程中，因為雜訊耦合議題考慮不周的關係而發生基板雜訊耦合的現象，因此在量測上使用基板分離的手段來使量測能夠順利進行•在850nm光波長下量測，設計之光接收器可因應不同的入射光強度作出適當的補償，在檢光二極體響應率為0.375A/W時，達到-9.8dBm的靈敏度，針對不同逆偏壓的檢光二極體，光接收器也能自動對高頻衰減作出不同程度的補償。負壓產生器在最小輸入光強度下產生-9V的輸出負壓以及17.6%的功率效率•設計的晶片面積為1mm×1mm，在1.8V供應電壓下消耗90mW的功率。

This thesis presents a monolithically integrated optical receiver, attempting to integrate a integrated photodiode, receiver front-end circuits and a negative voltage generator monolithically in standard CMOS process. The optical receiver adopts equalizer architecture to compensate the response of a photo-diode under different reverse-biased conditions. The source degeneration and active peaking techniques are adopted to improve the bandwidth up to 1.4GHz. This design is for adaptability of 850nm light wavelength under different power of light and different frequency response of the photo-diode. In order to collect all the laser from multi-mode fiber, the area of photo diode is 70μm× 70μm. A negative voltage generator provides a minus ten volts to enhance the intrisic response of the photo-diode. This generator will change clock frequency automatically under differnet input power of light to enhance the power efficiency. Due to a directly connection between the photo-diode and the negative voltage generator, suppressing the ripple signal from the generator so that there is no degradation on the performance of the optical receiver is an important design point. In this process of monolithically integration, substrate noise coupling is occurred due to a thoughtless consideration of the noise coupling issue. A substrate-separation method is taken to make the measurement successfully. Measurement results by using 850nm light wavelength achieve the adaptability of different light power of light and a sensitivity of -9.8dBm when responsivity of photo-diode is 0.375A/W. It also achieves the adaptability for different roll-off of different reverse-biased photo- diode. And the negative voltage generator provides -9V under the minimum input power of light, and reach a power efficiency of 17.6%. The chip dissipates 90mW from a 1.8V supply voltage and its area is 1mm×1mm.