Automatic Level Controlled Burst-mode Optical Fiber Amplifier for 10 Gbit/s PON application

Effective coexistence between normal- and extended-distance PON areas by using ALC-SOA

“…To meet this demand, some research groups have been studying the application of optical amplifiers given their advantages of transparency to frame format and signal bit rate, and simple management. They have developed novel optical amplifiers for PON applications [1,2,3,4,5,6] or intensively investigated the operating ranges of optically-amplified PONs [7,8,9]. In PON systems, there are two main optical splitter configurations: one is the single stage configuration, where a splitter with large splitting number is located outside the central office (CO), and the other is the dual stage configuration, where a second stage splitter is located inside the CO.…”

“…The solution is to apply the fast ALC circuit that we proposed in Ref. [6] to upstream signal amplification. The inset shows the configuration of the ALC burst-mode optical amplifier for upstream amplification in this paper; it consists of an SOA, the fast ALC circuit, and an optical band-pass filter (BPF).…”

“…While an optical fiber amplifier is implemented in Ref. [6], we utilize a SOA to handle the wavelength allocation defined in IEEE802.3av. Its gain and noise fig Fig.…”

1G / 10G coexistence long-reach PON system using ALC burst-mode SOAs

“…10G-EPON and XG-PON were standardized in IEEE and ITU-T, respectively, as the most promising candidate for the next generation optical access systems. In response to this movement, some research groups have started to study 10 Gb/s-class long-reach PONs [5,6,7]. To achieve smooth migration from 1 Gb/s to 10 Gb/s-class PONs, the specifications pursue the coexistence of both systems on a single optical line terminal (OLT), however, the possibilities of 1G / 10G dual-rate PONs using optical amplifiers are less well-studied [8,9].…”

“…The two optical band-pass filters have the flat pass-band of 3 nm, and eliminate the amplified spontaneous emission (ASE) light from the first SOA. The fast ALC circuit proposed in [6] is placed after the optical filters to keep the input optical powers to the second SOA constant regardless of the input powers to the first SOA. The time constant of the ALC circuit is around 50 ns.…”