Abstract

Adding or dropping channels due to the optical WDM network reconfiguration or faults leads to gain excursions of the erbium-doped fiber amplifier (EDFA). To stabilize the EDFA behaviour we combine optical feedback (OFB) [1] and electronic feedforward (EFF) control [2]. If EFF is used alone, a delay appears in the input signal power measurement and pump power setting due to the final time of the input photodiode (PD) response. It leads to the overshoots and undershoots in the displayed gain error (fig.1, curve 1). For OFB applied alone with λ_ofb =1530 nm a static gain error appears due to spectral hole burning (SHB) [1] (fig.1, curve 2). Additionally, a steady-state gain offset exists due to the EDFA gain saturation caused by OFB lasing.

© 2001 EPS