2.5Gb／sPIN—HEMT光接收机噪声精确模拟

本文给出了完整的ＰＩＮ和ＨＥＭＴ器件噪声等效电路模型。对２．５Ｇｂ／ｓＰＩＮ－ＨＥＭＴ光接收机噪声和灵敏度进行了精确的分析计算，并讨论了低频闪烁噪声对灵敏度退化的影响，光接收机噪声实测结果与模拟分析结果数据符合很好。     

高速光检测器和高速光接收机进展

本文综述了近年来微波光电子学中高速光检测器和高速光接收机的进展，分析并对比了各种光电二极管的响应速度、噪声及暗电流特性；指出光波导与ＭＳＭ、ＰＩＮ为代表的高速光电二极管以及ＨＥＭＴ、ＨＢＴ等低噪声微波器件的光电集成，是高速光接收机的发展趋势，行波光检测器作为高速分布参数光电器件，光波导与光电二极管的融合，光场效应晶体管以及掺铒光纤放大器的应用，都是值得重视的发展动态。     

高速光接收机前端的研究

本文从理论上分析了并联电感和串联电咸对ＰＩＮ－ＦＥＴ前端的作用，证明谐振电感可以有效地抑制ＦＥＴ热噪声的影响，在１．０－－１．５ＧＨｚ频率范围内得到拉近由量子散粒噪声决定的极限灵敏度。在实验上制作了ＨＧｚ级高速光接收机前端，并用微波网络分析仪测试了前端的频率响应。测试结果与理论分析基本相符。     

2．4Gb／s跨阻型光前置放大器CAD及验证

阐述了光纤通信前置放大器的设计原理，分析了光接收机中ＰＩＮ二极管和ＧａＡｓＦＥＴ器件的信号模型和噪声模型，提取了放大器用ＧａＡｓＦＥＴ器件的模型参数（包括大信号、小信号和噪声模型参数）。利用ＰＳＰＩＣＥ程序对光前置放大器进行了模拟分析和优化设计，并实际制作了用于２．４Ｇｂ／ｓ光纤通信的ＰＩＮ－ＨＥＭＴ前置放大器。实测结果表明放大器３ｄＢ带宽达到ＤＣ～４．４ＧＨｚ，增益为１８±１ｄＢ；加入ＰＩＮ二极管后的光接收模块的３ｄＢ带宽为ＤＣ～１．６８８ＧＨｚ，满足了２．４Ｇｂ／ｓ光纤通信的需要。     

高速光接收机前端的研究

本文从理论上分析了并联电感和串联电感对ＰＩＮ－ＦＥＴ前瑞的作用，证明谐振电感可以有效地抑制ＦＥＴ热噪声的影响，在１．０～１．５ＧＨｚ频率范围内得到接近由量子散粒噪声决定的极限灵敏度。在实验上制作了ＧＨｚ级高速光接收机前端，并用微波网络分析仪测试了前端的频率响应。测试结果与理论分析基本相符。     

提高国产激光器组件直接调制速率与PIN－FET组件频响带宽的新技术

本文对如何提高国产１．５５μｍＩｎＧｒａＡｓｐＤＦＢ－ＬＤ组件直接高速调制速率以及国产ＰＩＮ－ＦＥＴ组件的频响带宽进行了理论与实验研究。在实验测量的基础上建立了国产ＬＤ组件小信号等效电路模型，对其调制响应速率的主要限制因素进行了分析，研制了高速ＤＦＢ－ＬＤ组件，将其调制速率提高到３．２ＧＨｚ。同时，在对谐振式ＰＩＮ－ＦＥＴ光接收机进行噪声分析的基础上，采用微波混合集成工艺研制了一个串联谐振式ＰＩＮ－ＦＥＴ光接收组件，有效地提高了ＰＩＮ－ＦＥＴ的频响带宽。     

光纤放大器的ASE噪声对PIN接收机性能的影响及误码率计算

本文运用随机信号的分析方法推导了存在ＡＳＥ噪声情况下，光纤通信系统误码率的计算公式。利用该式可以根据信号光功率和噪声功率谱密度估算系统的误码率，与实验结果基本符合，从而可以为加光纤放大器的光纤通信系统提供评价信道优劣的依据。本文还论述了ＡＳＥ噪声对ＰＩＮ接收机灵敏度的影响，对于实际系统中接收机的选择具有重要意义     

一种0．85μm、10Mb／s PIN－FET厚膜集成光接收器的研制

本文介绍了一种适用于短距离光纤通信与光纤传感器的０．８５μｍ、１０Ｍｂ／ｓＰＩＮ－ＦＥＴ混合集成光接收器的基本原理。从ＰＩＮ－ＦＥＴ前置放大器出发，分析了热噪声因子Ζ的大小对接收器电路的热噪声均方电流的影响以及和接收器灵敏度的关系，指出了要改善ＰＩＮ－ＦＥＴ接收器灵敏度主要是提高品质因素ｇｍ／ＣＴ２。为照顾到低噪声、宽频带，又兼顾到动态范围，因而采用了跨阻抗放大器的实际电路。电路采用混合集成的厚膜工艺，整个接收器集成于１５×１０ｍｍ２基片上，再安装于２３×１８×８ｍｍ３双列直插式金属管壳内，由光纤引出。经过测试达到的上升、下降时间小于３０ｎｓ，带宽１０Ｍｂ／ｓ，最低接收灵敏度－４６ｄＢｍ。     

毫米波HEMT器件的开发与应用

报道了毫米波ＨＥＭＴ的发展及现状，介绍了低噪声和功率器件的一些相关技术和典型研究水平。并介绍了１２ＧＨｚ的低噪声ＨＥＭＴ在卫星电视接收机中的应用情况。     

毫米波HEMT器件的电路模型研究

提出一种在微波与毫米波段快速、精确地建立ＨＥＭＴ器件等效电路的新方法，并对ＨＥＭＴ器件的噪声模型及参数的提取方式进行了研究．给出了等效电路模型（２～６０ＧＨｚ）和噪声模型（２～２６ＧＨｚ）的数值结果．     

Effect of nonuniform laser FM response on the performance ofmultichannel heterodyne FSK systems using optical amplifiers

A theoretical analysis is provided to evaluate the performance of optical frequency division multiplexed systems taking into considerations the combined effect of receiver noise, laser phase noise and nonuniform FM response characteristic of a practical DFB laser. To overcome the effect of nonuniform frequency modulation characteristic of semiconductor lasers, two different linecoding schemes are used for the laser driving signal. The crosstalk penalty due to the combined effect of nonuniform FM response and phase noise of lasers is evaluated. The improvement in receiver sensitivity due to optical preamplifier is also estimated. The computed results show that the performance of the system is highly degraded due to the effect of laser nonuniform fm response and can be reduced substantially by using linecoding. Further, there is considerable improvement in receiver sensitivity due to the use of an optical preamplifier in the absence of phase noise. In the presence of phase noise there is a reduction in receiver sensitivity     

Optical preamplifier receiver for spectrum-sliced WDM

Spectrum-slicing provides a low-cost alternative to the use of multiple coherent lasers for wavelength division multiplexing (WDM) applications by utilizing spectral slices of a single broadband noise source for creating the multichannel system. In this paper we analyze the performance of both p-i-n and optical preamplifier receivers for spectrum-sliced WDM using actual noise distributions, and the results are compared with those using the Gaussian approximation. This extends prior results of Marcuse for the detection of deterministic signals in the presence of optical amplifier and receiver noise. Although the methodology is similar, the results are considerably different when the signal is itself noise-like. For the case of noise-like signals, it is shown that when an optical preamplifier receiver is used, there exists an optimum filter bandwidth which minimizes the detection sensitivity for a given error probability. Moreover the evaluated detection sensitivity, in photons/bit, represents an order of magnitude (>10 dB) improvement over conventional detection techniques that employ p-i-n receivers. The Gaussian approximation is shown to be overly conservative when dealing with small ratios of the receiver optical to electrical bandwidth, for both p-i-n and preamplifier receivers     

带前置光放大器的光接收机灵敏度分析

本文分析了半导体光放大器的噪声特性，并首次推导出带前置光放大器的接收机灵敏度公式。结果表明，除光放大器内增益外，光放大器入射端耦合效率是影响这种接收机灵敏度的主要因素，而且其最佳判电平高于原接收机。     

Sensitivity enhancement of optical receivers by impulsive coding

A theory for the signal-to-noise ratio (SNR) of optical direct-detection receivers employing return-to-zero (RZ) coding (and possibly optical preamplification) is developed. The results are valid for both signal-independent noise limited and signal-dependent noise limited receivers, as well as for arbitrary optical pulse shapes and receiver filter characteristics. Even if the same receiver bandwidth is used, RZ coding is seen to perform better than nonreturn-to-zero (NRZ) coding. Asymptotic expressions for the SNR in case of very high and very low receiver bandwidths show that the full sensitivity enhancement potential of RZ coding is exhausted at fairly moderate duty cycles. A realistic example taking into account intersymbol interference (ISI) shows that a receiver sensitivity gain (compared to NRZ coding) of, e.g., 3.2 dB can be obtained in a signal-independent noise limited receiver with a bandwidth of 80% of the data rate, using a duty cycle of three     

用于微光探测的高灵敏度接收机设计

详细分析了光接收机噪声源及噪声模型,研究了其系统组成与电路设计问题,提出了可用于微光探测系统的接收机设计方案。选用合适的器件,采用低噪声电路设计方法,制作了实际光接收机电路,并进行了相应实验测试。结果表明,该设计方案可以满足实际微光探测要求,对应用于不同系统的高灵敏度光接收机设计具有较强的参考价值。     

Receiver Design for Digital Fiber Optic Transmission Systems Using Manchester (Biphase) Coding

An analysis of the sensitivity of an optical receiver in a digital communication system using Manchester (biphase) coding is performed. Both cases of p-i-n and avalanche photodiodes are considered. Experimental results for the sensitivity of a Manchester receiver operating at 250 Mbits/s are reported. Two types of low noise receiver amplifiers, namely the high impedance and the transimpedance amplifier, are designed and implemented for use in the receiver. A receiver sensitivity of -49.8 dBm in terms of detected optical power is obtained (at a 10^-9bit error rate and 0.1 laser extinction ratio), which corresponds to only 175 average photons per bit. It is shown that in contrast to the NRZ code, the Gaussian approximation theory tends to underestimate the Manchester receiver sensitivity. Tradeoffs between Manchester and NRZ coding are also discussed in terms of receiver sensitivity and ease of implementation. It is shown that Manchester coding is an attractive alternative to NRZ coding for optical transmission systems, particularly when an avalanche photodiode is used.     

Integrated optical E-field sensors with a balanced detection scheme

Compact and nonperturbing integrated optical E-field sensors are used for electric field measurements. The theoretical sensitivity of an integrated optical sensor system is limited by the shot noise. In conventional sensors, however the minimum detectable electric field strength is limited by the relative intensity noise (RIN) of the laser diode. Achieving the theoretical sensitivity a new sensor system is presented. Using a balanced optical receiver both a signal gain and a reduction of the RIN at the optical receiver is obtained. The principle function and the potential of the balanced detection scheme in comparison with existing concepts as well as first measurements are presented, yielding a sensitivity of less than 300 μV/(m√Hz) with standard laser diodes and a receiving dipole length of 40 mm     

光纤通信接收机放大器的等效噪声模型

许多光纤通信文献给出了如图1所示的光接收放大器的等效噪声模型。本文证明了这个等效噪声模型与原始噪声模型不等价，并且也不具有可测性。所以，这个等效噪声模型是不正确的，因而不宜采用。作者认为，在光纤通信接收机的设计中，噪声计算只是为了分析接收机的灵敏度，而不是用来确定最佳信号源电阻，因而可以不用等效噪声模型，直接用原始的噪声模型反而更简单和更精确。     

Phase noise cancellation in a carrier recovered optical heterodynereceiver

The performance and application of an optical heterodyne receiver which uses a carrier recovery demodulator are described. Phase sensitive demodulators used in coherent optical transmission are compared, and the suppression of both phase noise and frequency instability of light sources by a carrier recovery (CR-) demodulator is described. A carrier recovered PSK (CR-PSK) demodulator and a phase noise canceling circuit (PNC) for a coherent SCM receiver are introduced as examples of CR-demodulators. The relationship between laser diode spectral linewidths and the delay time difference between the two paths in the CR-PSK demodulator necessary to keep the system performance within a certain power penalty is then derived. In a preliminary experiment using 560-Mb/s CR-PSK transmission, a receiver sensitivity of -51.6 dBm was obtained, and a laser phase noise suppression of about ¹/₂ that of DPSK was confirmed. The results suggest the possibility of constructing a heterodyne receiver which has no AFC-loop. Applications of a CR-demodulator to an optical frequency division multiplexing (OFDM) system and to a multivalue modulation scheme are discussed     

Receiver design for high-speed optical-fiber systems

The technology of optical-fiber systems is advancing rapidly. Parallel to the development of long-haul telecommunication systems in the gigabits per second data rates operating in the long-wavelength region is the wide penetration of optical-fiber systems in local area networks, video trunking and distribution, sensors, etc. These diversified applications impose different and often conflicting constraints on the optical receiver. This paper re-examines the optical receiver design in view of these different requirements, namely, high receiver sensitivity, wide dynamic range, transparent to the operating bit rate, unrestricted data format, and fast acquisition time. Design tradeoffs between conflicting receiver requirements are considered in detail. In particular, the sensitivity of high-capacity long-wavelength transmission systems is emphasized. The state-of-the-art performance of photodetectors and low-noise amplifiers is discussed. We show that dark current of avalanche photodiodes (APD's) is the main factor limiting the sensitivity of long-wavelength optical receivers. In addition, as an example, we report on the design and experimental performance of a hybridized low-noise optical receiver amplifier capable of more than 2-Gbits/s operation. The input noise spectral density achieved is 9 pA/sqrt{Hz}with a noise corner frequency of 920 MHz, corresponding to an equivalent noise resistance of 120 Ω.