Performance analysis of interferometric noise due to unequally powered interferers in optical networks

Abstract

Abstract-Interferometric crosstalk has been identified as the cause of performance limits in future transparent all-optical networks. A large number of studies have been conducted on this phenomenon using a vast array of evaluation techniques. However, most major studies have considered that although the interfering terms may differ in number, the power contribution that they all make will be identical for all interfering terms. Although this situation is easy to analyze, it does not necessarily represent the situation that is likely to occur in a real network, which will be constructed of nodes with different degrees of connectivity, quite possibly from different vendors, and therefore with differing crosstalk characteristics. This paper describes a study on the impact of unequally powered interfering terms using a rigorous analysis technique. To validate the use of the chosen technique, the paper begins by benchmarking a number of common evaluation techniques against empirically derived, experimentally verified noise performance formulas.

OSNR Penalty Imposed by Linear In-Band Crosstalk Caused by Interburst Residual Power in Multipoint-To-Point Networks

“…The crosstalk term is essentially a sum of random terms and can be interpreted as intensity noise [4]. As the amount of interferers is typically relatively high, the central limit theorem can be used with good accuracy, leading to a Gaussian approach [5], [6]. The crosstalk variance is found as the mean square value of the crosstalk current (2) In an intensity modulated system with average received power and extinction ratio , the variances on one and zero levels are then given by (3) with (4) In this equation, is the ratio of the received signal power to the average received interburst power and, for a given network configuration and ONU, is a constant.…”

“…The dominant noise terms at the receiver are signal-crosstalk beat noise [given by (3)] and signal-ASE beat noise, given by (5) In these equations, is the electrical receiver bandwidth, and is the ASE spectral density in one polarization. The optical signal-to-noise ratio (OSNR) at the receiver is given by , with the reference bandwidth of the OSNR measurement, and substitution yields (6) The -factor at the receiver, which directly determines the biterror rate (BER) through , is given by (7) Solving for OSNR yields (8) One can now define the crosstalk imposed OSNR penalty as the ratio of the OSNR requirement in a system with crosstalk to that in the same system without crosstalk (9) When the signal and the interferers encounter exactly the same loss, is the ratio between the average launched signal power and the interburst residual power .…”

Impact of Receiver on In-Band Crosstalk-Induced Penalties in Differentially Phase-Modulated Signals

“…In-band crosstalk could be one of the main factors limiting the performance of wavelength-division-multiplexed (WDM) transport networks [1][2][3][4][5][6][7][8]. This crosstalk could be generated, for example, at imperfect optical add-drop multiplexers, or by double Rayleigh backscattering in distributed Raman amplified systems [3][4][5][6][7][8].…”

“…This crosstalk could be generated, for example, at imperfect optical add-drop multiplexers, or by double Rayleigh backscattering in distributed Raman amplified systems [3][4][5][6][7][8]. To estimate the scalability of such WDM transport networks, it is important to evaluate accurately the power penalty induced by in-band crosstalk.…”

Interferometric Noise Characterisation of a 2-D Time Spreading Wavelength Hopping OCDMA Networks using FBG Encoding/Decoding

“…The performance of OCDMA systems at the physical level is limited by a combination of noise sources, the more critical being multiple access interference (MAI) and interferometric noise (IN) [1][2][3]. Most optical systems are prone to IN viz.…”