Erbium Amplifier Dynamics in Wireless Analog Optical Links With Modulator Bias Optimization

Modulator bias optimization is a technique used to improve the transmitted radio-frequency power of amplified analog optical links. However, when bias optimization is used, the mean optical power at the modulator output is dependent on the amplitude of the modulation signal. In this letter, we show how fluctuations of the modulation signal power, in conjunction with the dynamic behavior of the erbium optical amplifier, can deteriorate the transmission of data frames compliant to the 802.11 a/g IEEE protocol. Optical and electrical compensating methods, based on mean power clamping at the modulator output, are proposed, and their efficiency in restoring a high-quality transmission is demonstrated.