由於在最後英里(last mile)對資料頻寬的需求日益增加，所以發展出乙太被動光纖接取網路這種全新的技術去解決在未來裡對於資料傳輸能力的需求。基於光纖到家和點對多點的光纖網路架構，它超過能提供1 Gbps 的資料速度去符合多媒體的傳輸。 這篇論文提到脈衝式前級接收機的設計，它包含一個轉阻放大器(transimpedance amplifier, TIA)和一個後級限制放大器(limiting amplifier, LIA)，為了去驗證低雜訊的設計技術用著巴特握夫(Butterworth)和貝索(Bessel)模式的轉阻放大器被推薦來分析和他們的特性來比較碼際干擾(ISI)和一些觀點，這裡也有用到當增益改變時，去維持固定的震盪因子(damping factor)的方法去維持穩定度和群延遲。 在我的論文中，我們就是利用TSMC .18μm CMOS來完成一個操作在1.8v 2.5 Gbps的 CMOS 脈衝式(Burst mode)光纖前級接收端電路。在脈衝式光纖前級接收端的電路中，由於要在很短的時間內能正常的放大訊號，我們在這採用直流偶合和前餽補償誤差的技巧。轉阻放大器接受到由光二極體產生的光電流並將它轉為電壓訊號輸出，由於轉阻放大器的輸出為單相位輸出，所以需要一個自動門檻控制電路產生一個門檻電壓把它轉成差動訊號在輸入到限制放大器。之後再由限制放大器將電壓放大到具有固定振幅的輸出訊號。為了提高輸入訊號動態範圍，在轉阻放大器中包含了切換增益模式的電路。在1.8V的操作電壓下，轉阻放大器提供一個66dB?和1.96GHz的-3dB頻寬。至於限制放大器的設計，我們採用主動迴授的方式來讓每一點呈現低阻抗和沒有負載效應的損失。在1.8V的操作電壓下，限制放大器有11.4mV的敏感度、3GHz的-3dB頻寬和32.6dB的增益，而且輸出被限制在有660mV的電壓振幅。 With the increasing demands at data bandwidth in the last mile, network access Ethernet optical network (EPON) is considered on a promising technology to meet the demands of data transmission capability in the future. Based on fiber to the home (FTTH) technology and point-to-multipoint optical network configuration. It provides up to 1 Gbps data rate which is suitable for multi media communication. This thesis describes the design of burst mode receiver front-end, including a transimpedance amplifier (TIA) and a post limiting amplifier (LIA). To investigate low noise design technology with Butterworth and Bessel type TIAs are proposed analysis and their characteristic are compared in which from ISI and main points of view. Also, a method of novel constant damping factor is to maintain stability and group delay when gain switches. This thesis explores circuit techniques for optical receiver front-end design in 0.18μm CMOS technology. The objective goals of this research are to realize a single chip of 1.8V 2.5 Gbps burst mode optical receiver front-end ICs. In the receiver front-end circuit, in order to amplifying signal correctly in short time. We adopt the skills of DC couple and feed-forward offset cancellation. the transimpedance amplifier receives the photocurrent produced by photodiode and transforms it to voltage output. Because the output of TIA is single phase signals, we need ATC to produce the threshold voltage to change the signal into the differential signal to input to LIA. The limiting amplifier further enlarges the tiny voltage to a fixed and sufficiently large output voltage. In order to enhance the input dynamic range, an automatic switch gain control circuit is included in TIA design. Under 1.8V supply voltage, the TIA provides a conversion gain of 66dB? with a –3dB bandwidth of 1.96GHz, and its input dynamic range is from –25dBm to -6dBm. In the design of limiting amplifier, we adopt the method of active feedback to make every node to present low impedance, and has no loss of loading effect. It achieves an input sensitivity of 11.4mV, -3dB bandwidth of 3GHz and conversion gain of 32.6dB, and the output voltage is fixed at 660mV under 1.8V voltage operation.
