Receiver Design for Digital Fiber Optic Communication Systems, I

Abstract

This paper is concerned with a systematic approach to the design of the “linear channel” of a repeater for a digital fiber optic communication system. In particular, it is concerned with how one properly chooses the front‐end preamplifier and biasing circuitry for the photodetector; and how the required power to achieve a desired error rate varies with the bit rate, the received optical pulse shape, and the desired baseband‐equalized output pulse shape. It is shown that a proper front‐end design incorporates a high‐impedance preamplifier which tends to integrate the detector output. This must be followed by proper equalization in the later stages of the linear channel. The baseband signal‐to‐noise ratio is calculated as a function of the preamplifier parameters. Such a design provides significant reduction in the required optical power and/or required avalanche gain when compared to a design which does not integrate initially. It is shown that, when the received optical pulses overlap and when the optical channel is behaving linearly in power,1 baseband equalization can be used to separate the pulses with a practical but significant increase in required optical power. This required power penalty is calculated as a function of the input and equalized pulse shapes.

Joint Probability Density Functions for Direct-Detection Optical Receivers

“…2 where both JPDFs have the same value. The area of each JPDF beyond that line contributes to the BER [5] which is evaluated numerically as 6.8×10 -6 . This corresponds to about 0.5 dB enhancement in A 1 compared with the conventional BER of 2.2×10 -5 .…”

“…Conventional optical receivers for IM/DD systems use a single data per single bit for the decision [5] and require clock recovery circuits. If we could use multiple data for the decision, we do not need the clock recovery circuits [4] while enhancing the receiver sensitivities.…”

Time-dependent Analysis of Optical Receivers Using Receiver Eigenmodes

“…To increase the transmission distances, optical receivers suffer from various electrical and optical noises. In early optical communication systems, shot and thermal noises limit the receiver performances dominantly [1,2]. After the appearance of optical amplifiers, the amplified-spontaneous emission (ASE) becomes the most dominant noise source that mixes with the optical channel at the photo-detector [3][4][5].…”

The effects of optimized regenerator allocation in translucent networks under inaccurate physical information

“…This parameter allows capturing the effects of all PLIs on each optical circuit, in order to evaluate the optical signal quality. This single output parameter collecting all the PLI effects is commonly called quality factor parameter Q [3] [4] [5]. In this paper, we consider IA-RWA algorithms relying on the Q Personick's factor [3], as the optical signal performance parameter.…”