Digital Baseband Circuit Design for High-speed Optical Communication (II)

在廣域網路(Wide-area Network)中， 光學訊號需要橫越非常長的距離 (>1000km)，其中會經過許多的光學儀器 ( 如： Optical Add/Drop Mux 、Optical Cross-connects 等)，在長距離傳輸會受到 光學信號破壞而導致信號的衰減。這些信 號破壞可以利用光學上技術來補償，如： 擴散補償纖維(Dispersion Compensating Fiber)和光學極化模式擴散(Polarization Mode Dispersion)補償。可是由於這些光學 上的技術欠缺彈性且高成本，所以目前的 趨勢為利用電子電路補償來取代光學補 償，以降低成本及提供更彈性的設計。 在這個計劃中，我們利用在電子積體 電路中可調適等化器和前饋式錯誤更正 碼(FEC)的技術來補償光纖通訊中信號的 衰減和破壞。在設計可調適等化器 (Adaptive Decision Feedback Equalizer)和 前饋式錯誤正碼(Forward Error Correcting Code)模組方面，我們將會嘗試從演算法 找出降低系統的面積和功率消耗的方法. 進一步發展出具有更高效率地管線化或 平行化的可調適等化器和前饋式錯誤正 碼模組的架構.最後在電路層次上針對面 積和功率作最佳化.In Wide-area Network (WAN), optical signals may traverse long distances (up to thousands of kilometer) and encounter numerous optical devices such as optical add/drop multiplexers, optical cross-connects, etc. This causes degradation of the signal due to optical impairments in the long-haul link. Some of these impairments, such as dispersion, can be compensated optically. Dispersion Compensating Fiber (DCF) and optical Polarization Mode Dispersion (PMD) compensators are examples of such optical components [1]. Due to lack of flexibility and also high cost of these optical solutions, electronic compensation may be a better choice in order to reduce the costs and provide more flexibility. In this project, we exploit the electronic integrated circuit solutions by using the Digital Adaptive Equalization and Forward Error Correcting Code (FEC) techniques to compensate for the impairments of optical communication. In the designs of digital adaptive equalizer and FEC modules, we will seek for efficient algorithmic-level improvement for Adaptive Decision Feedback Equalizer (ADFE) and FEC modules, to reduce the areas and power dissipations. Moreover, the pipelined or parallel architecture of ADFE and FEC modules will be developed to obtain the very high-speed VLSI architecture. Finally, the circuit level optimization for power and areas will be employed in our VLSI architecture for ADFE and FEC modules