All-Optical Gain Controlled EDFA: Design and System Impact

Abstract

Abstract. An erbium doped fiber amplifier with automatic gain control was designed using the all-optical gain control technique. The amplifier performance for different control channel wavelengths and feedback loop attenuation values was experimentally investigated under static and dynamic conditions by measuring the bit error rate of a 2.5-Gb/s 8-channel DWDM system.

Evaluation of transient dynamic impact in gain controlled EDFAs

“…3 presents the measured results. The AOGC-EDFA was designed to minimize the influence of relaxation oscillations in accordance to [6] and to give an average amplifier gain of 20 dB/channel, with gain variations below 0.5 dB after add/drop, though proper adjustments of the optical feedback attenuation. Fig.…”

“…Both EGC-EDFA modes operated as boosters, with the eight input channels set at -4.3 dBm/channel (4.7 dBm in total). The AOGC-EDFA was implemented by using optical feedback with variable attenuation [6]. Its operation as a booster was avoided due to the low ASE level generated as consequence of the high input power level, which can prevent the control laser of reaching its threshold.…”

A multilevel gain all‐optical gain‐controlled EDFA with suppressed relaxation oscillations

“…Another limitation factor in AOGC-EDFAs is the SHB [5], which can produce cross-gain modulation among closely spaced channels. The ROs and SHB can be significantly suppressed by an appropriate choice of the control-channel wavelength and an optimization of the loop-attenuation level [5][6][7][8].…”

“…Since the last decade, several techniques have been proposed to control the EDFA dynamic gain: electronic [2], all-optical [3], and hybrid [4]. Especially, the alloptical gain-control technique has been extensively analyzed due to its simplicity and low cost, where limiting factors such as spectral hole burning (SHB) and relaxation oscillations (ROs) have been investigated in detail [5,6]. In particular, the optical feedback loop attenuation plays an important role in the control technique, since it is responsible for the SHB reduction and the amplifier gain per transmitted channel.…”

“…In this paper, the design and characterization of an all-optical gain-controlled EDFA (AOGC-EDFA) using an embedded fast variable optical attenuator (FVOA) in the feedback loop are presented. With this approach and considering a proper choice of control-channel wavelength [6], the amplifier gain can be set at fixed values with small gain variations and the absence of ROs during channel adding and dropping by only adjusting the FVOA attenuation level. Also, the controlled EDFA noise figure is similar to that of an equivalent conventional EDFA, unlike former results for different AOGC-EDFA configurations [7].…”