Wireless signal-preamble assisted Mach-Zehnder modulator bias stabilisation in wireless signal transmission over optical fibre
✍ Scribed by Chanda, Debashis ;Sesay, Abu
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 178 KB
- Volume
- 19
- Category
- Article
- ISSN
- 1124-318X
- DOI
- 10.1002/ett.1253
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✦ Synopsis
Abstract
Lithium niobate based Mach–Zehnder electro‐optic modulators are increasingly being used in high‐speed digital as well as analog optical links. Depending on the application, digital or analog, the bias point of such a modulator is held constant at a particular point on the sinusoidal electrical to optical power transfer characteristics of the modulator. Bias point drift is one of the major limitations of lithium niobate based Mach–Zehnder electro‐optic modulators. This increases the bit error rate of the system and affects adjacent channel performances. In one of the most popular methods of bias control, a pilot tone is used to track the bias point drift. However, pilot tone based bias tracking reduces overall intermodulation free dynamic range of the link. In this paper we propose a method where Mach–Zehnder modulator bias drift is tracked and maintained at the desired point by tracking the power variation of the preamble of wireless signal data frames. The method has no detrimental effects on system performances as no external signal is exclusively injected into the system for bias tracking purposes. Copyright © 2007 John Wiley & Sons, Ltd.