CMOS Optical Preamplifier Design Using Graphical Circuit Analysis

More documents

Recommendations

Info

CHAPTER 2 Background This chapter provides the background needed for the thesis. The chapter begins with an overview of photodetectors, optical preamplifiers, and transimpedance amplifiers. It then discusses the receiver design requirements, and reviews previ- ously reported solutions. Having provided a context for our work on optical preamplifiers, the chapter focuses on the circuit analysis aspects of this thesis by discussing the limitations of current circuit analysis techniques, providing a basic review of signal-flow graphs, and discussing the motivation for DPI/SFG analysis. The development of fiber-optic communications can be traced back to the 1970’s. Since that time, an extensive body of literature has developed for optical receivers and photodetectors for fiber-optic applications that can provide the inter- ested reader with a more comprehensive treatment of these subjects [Kressel,1982], [Personick,1985], [Miller,1988], [Alexander,1997]. In addition, there are two excellent references that deal specifically with optical wireless systems, their opto- electronics, and other design issues at the circuits and system level [Barry,1994], [Hranilovic,1999]. 2.1 PHOTODETECTORS Photodetectors are semiconductor devices that convert incident light into an electric current. There are various types of photodetectors such as photovoltaic cells, photodiodes, and phototransistors. For high-speed optical communications, photodiodes are preferred given their superior frequency response. Photodiodes are usually operated under reverse-bias conditions. Like other semiconductor diodes, photodiodes possess a finite carrier transit time. From a circuit design standpoint, however, we can suitably model the photodiode’s electrical behaviour with the small-signal equivalent circuit model shown in Figure 2.1. 10
E e + - V bias 2.1 Photodetectors 11 The main photocurrent, , is generated through the creation of electron-hole pairs when photons from the incident light penetrate the diode. The sensitivity of the photodetector is a function of the wavelength, and so to maximize power efficiency, the emission wavelength of the optical source should be spectrally matched to the photodiode. Silicon photodiodes, which are commonly used in low-cost applications, have a peak spectral efficiency in the near infrared region. Figure 2.2 shows the normalized spectral sensitivity of a typical silicon photodiode 1 , and shows how it is spectrally matched to GaAs LEDs (e.g. Temic TSHF5400). Relative sensitivity (%) 1. Data taken from Temic’s BPV22NF photodiode. i s Figure 2.1 Small-signal equivalent circuit model of photodiode. 100 90 80 80 Relative sensitivity (%) 70 60 60 50 40 40 30 20 20 10 0 GaP:N LED i s GaAsP LED GaAs LED 2 I n GaAs:Si LED C d Si photodiode R s + V bias 0 300 400 300 Ultra- 500 600 Visible 700 800 900 1000 Near 1100 1200 1300 1400 1500 violet light infrared Wavelength (nm) Ultraviolet Visible Near infrared Wavelength(nm) Figure 2.2 Relative spectral sensitivity of Temic BPV22NF silicon photodiode and emission peaks of several types of LEDs. -
Page 1 and 2: CMOS Optical Preamplifier Design Us
Page 3 and 4: To achieve low-voltage operation, w
Page 5 and 6: Table of Contents CHAPTER 1 INTRODU
Page 7 and 8: CHAPTER 1 1.1 OVERVIEW Introduction
Page 9 and 10: Information Source Modulator Drive
Page 11 and 12: 1.2 Thesis Outline 5 [Ohhata,1999].
Page 13 and 14: 1.2 Thesis Outline 7 technique call
Page 15: 1.2 Thesis Outline 9 Detector in St
Page 19 and 20: Diode Capacitance (pF) Diode capaci
Page 21 and 22: 2.2 Optical Preamplifier Structures
Page 23 and 24: 2.3 Transimpedance Amplifier Design
Page 27 and 28: I dc 2.3 Transimpedance Amplifier D
Page 31 and 32: Source Figure 2.11 General structur
Page 33 and 34: A = = For = 1V , the solution is v
Page 35 and 36: The gain of the forward amplifier c
Page 37 and 38: Feedback Analysis Using Return Rati
Page 39 and 40: 2.4 Circuit Analysis Techniques 33
Page 41 and 42: 2.5 An Overview of Signal-Flow Grap
Page 43 and 44: 1 x1 x2 2.5 An Overview of Signal-F
Page 45 and 46: 2.6 SUMMARY REFERENCES • ∆ k =
Page 47 and 48: Symp. Circuits Systems, vol. 3, pp.
Page 49 and 50: CHAPTER 3 New Transimpedance Amplif
Page 51 and 52: 3.1 A Differential Transimpedance A
Page 57 and 58: 3.2 A Feedback Topology for Ambient
Page 59 and 60: 3.2 A Feedback Topology for Ambient
Page 61 and 62: Transimpedance (dBΩ) 90 80 60 40
Page 63 and 64: 3.3 A Low-Voltage Transimpedance Am
Page 65 and 66: 3.3 A Low-Voltage Transimpedance Am
Page 67 and 68:
3.3 A Low-Voltage Transimpedance Am
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
C 3 Φ1VB M 3 V B- =0.7V M 7 Figure
Page 75 and 76:
Page 77 and 78:
3.4 SUMMARY 3.4 Summary 71 In this
Page 79 and 80:
3.4 Summary 73 Y. Nakagome et al.,
Page 81 and 82:
4.1 Introduction 75 back topology o
Page 83 and 84:
4.2 Circuit Analysis Using Driving-
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
4.3 DPI/SFG: Combining DPI Analysis
Page 93 and 94:
4.4 Determining Port Impedances 87
Page 95 and 96:
v i R in v o R out 4.4 Determining
Page 97 and 98:
id » ro and 1 ⁄ rid « Av ⁄ ro
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Z b r e g m 4.5 Analyzing Transisto
Page 105 and 106:
4.5 Analyzing Transistor Circuits 9
Page 107 and 108:
Figure 4.25 SFG for the source foll
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
5.1 Analysis of the Low-Voltage Tra
Page 117 and 118:
5.1 Analysis of the Low-Voltage Tra
Page 119 and 120:
5.2 DEVELOPING AN ANALYTIC CIRCUIT
Page 121 and 122:
Z in 5.2 Developing an Analytic Cir
Page 123 and 124:
5.2 Developing an Analytic Circuit
Page 125 and 126:
I n1 : i in I n2 -I n1 i scin ( sCi
Page 127 and 128:
Page 129 and 130:
I nRf : 5.2 Developing an Analytic
Page 131 and 132:
DC transimpedance gain: Pole locati
Page 133 and 134:
Frequency (MHz) 500 450 400 350 300
Page 135 and 136:
Pole frequencies(MHz) 500 450 400 3
Page 137 and 138:
Optimizing Sensitivity 5.2 Developi
Page 139 and 140:
Page 141 and 142:
Transimpedance Volts dB (lin) Gain
Page 143 and 144:
CHAPTER 6 Implementation and Experi
Page 145 and 146:
6.1 A 1V Optical Receiver Front-End
Page 147 and 148:
Page 149 and 150:
6.1.2 Experimental Results 6.1 A 1V
Page 151 and 152:
Gain(dB) 0 −1 −2 −3 −4 −5
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Clock signal of voltage doubler Eye
Page 161 and 162:
6.2 Variable-Gain Transimpedance Am
Page 163 and 164:
6.2.2 Experimental Results 6.2 Vari
Page 165 and 166:
6.3 Summary and State-of-the-Art Co
Page 167 and 168:
Reference Outputs Technology Supply
Page 169 and 170:
CHAPTER 7 Conclusions 7.1 SUMMARY A
Page 171 and 172:
7.2 Future Work 165 The significanc
Page 173 and 174:
7.2 Future Work 167 supply and subs
Page 175 and 176:
v s i ti that part of the SFG for Q
Page 177 and 178:
Thus, P1 ′ = b = 500Ω ∆1 ′
Page 179 and 180:
itive representation of circuit dyn
Page 181 and 182:
Bipolar Transistor i scb Z b v b b
show all

CMOS Optical Preamplifier Design Using Graphical Circuit Analysis

Create successful ePaper yourself

Delete template?

Save as template?