Fiber Preamplifier Research Articles

High receiver sensitivity at 10 Gb/s using an Er-doped fiber preamplifier pumped with a 0.98 mu m laser diode

The authors report the realization of an extremely high receiver sensitivity at 10 Gb/s by using an erbium doped fiber (EDF) preamplifier pumped with a 0.98 mu m laser diode. The obtained EDF input sensitivity is -37.2 dBm (147 photons/bit). In addition, the importance of minimizing reflection from amplifier fiber ends is shown. >

Effect of gain saturation on receiver sensitivity in 1 Gb/s multichannel FSK direct-detection systems using erbium-doped fiber preamplifiers

The effects of gain saturation on receiver sensitivity were studied theoretically and experimentally when using an erbium-doped fiber amplifier (EDFA) in a frequency-shift-keyed direct-detection system. It was found that when the amplifier undergoes a 6-dB gain compression due to saturation by a strong adjacent signal, the power penalty at 10/sup 9/ bit-error-rate (BER) is less than 1.5 dB. This power penalty increases rapidly when saturation is greater than 6 dB. Such a penalty increase with EDFA gain saturation is explained by the observed changes in the spontaneous emission noise factor and in the relative contribution of the circuit noise and is closely predicted by the theoretical analysis. These results demonstrate the possibility of using a saturated EDFA preamplifier while accommodating as many as several hundred optical channels or potential network users without incurring significant BER degradation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

High-sensitivity FSK signal detection with an erbium-doped fiber preamplifier and Fabry-Perot etalon demodulation

A report is presented on a 622-Mb/s optical transmission system with demodulation of alternate mark invert (AMI) encoded frequency shift keying (FSK) signals by a Fabry-Perot etalon. A 25-dB gain erbium-doped fiber preamplifier gave a receiver sensitivity of -40 dBm at 10/sup -9/ BER, which was improved to -44 dBm with the addition of a narrowband optical filter. The theoretical sensitivity of the preamplified receiver and the effect of the etalon on the amplified spontaneous emission beat noise are discussed and related to experiment.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

152 photons per bit detection at 622 Mbit/s to 2.5 Gbit/s using an erbium fibre preamplifier

An erbium fibre preamplifier, pumped at 980 nm, has been used to achieve the best reported direct detection sensitivities at 2.5Gbit/s, 1.2Gbit/s, 622 Mbit/s of −43.0 dBm, −45.6 dBm and −49 dBm, respectively. The amplifier had a noise figure of 3.3 dB, which is one of the best reported.

Use of LD-pumped erbium-doped fiber preamplifiers with optimal noise filtering in a FDMA-FSK 1 Gb/s star network

An erbium-doped fiber amplifier was implemented in a closely spaced FDMA-FSK (frequency-division-multiple-access-frequency-shift-keyed) optical star network with a signaling rate of 1 Gb/s per channel. The fiber preamplifier, which is laser-diode pumped, increases the sensitivity of the direct-detection avalanche photodiode (APD) receiver by 14 dB, allowing for an increased number of network users. This enhanced sensitivity nearly corresponds to all of the available gain of the amplifier. Furthermore, the amplifier noise is optimally filtered by means of a wide band interference filter cascaded with a narrow band fiber Fabry-Perot filter. >

Broadband, high sensitivity erbium amplifier receiver for operation over wide wavelength range

The sensitivity of an ultra-broadband optical receiver, built using discrete commercial components, was improved by 13.4 dB giving −32.4 dBm at 5 Gbit/s, by employing an erbium doped fibre pre-amplifier. Results also showed a maximum sensitivity variation of 2.1 dB over a 30 nm wavelength range.

Rayleigh scattering influence on performance of 10 Gb/s optical receiver with Er-doped optical fiber preamplifier

The achievement of -30.8 dBm (630 photon/bit) receiver sensitivity at 10 Gb/s, with an Er/sup 3+/-doped optical fiber preamplifier, is discussed. This is an 8.3-dB sensitivity improvement over the avalanche-photodiode/FET receiver. Power penalties caused by a noise increase due to Rayleigh backscattering by the transmission optical fiber have been evaluated. Approximately -30-dB Rayleigh scattering from a 20-km optical fiber resulted in a 3.5-dB power penalty for a 25-dB-gain optical amplifier.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

FM microwave multiplexed broad-band distribution systems using Er/sup 3+/ fiber amplifiers and preamplifiers

The use of an Er/sup 3+/ fiber preamplifier for microwave multiplexed systems and the use of an inline Er/sup 3+/ amplifier in microwave multiplexed systems for signal distribution are reported. The improvement in receiver sensitivity as a preamplifier, without optical filtering, was 9 dB. No power penalty due to amplified spontaneous emission was found when the amplifier was used in a 30-channel signal distribution system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Design and performance of a long-span IM/DD optical transmission system using remotely pumped optical amplifiers

Novel optical transmission system configurations which use remotely pumped fibre amplifiers are proposed to increase repeater spacings. The configurations and properties of major optical components, such as the Er-doped fibre pre-amplifier and booster amplifier, developed for this system, are described. Also Raman amplification for a dispersion shifted fibre and its high power optical signal handling capacity are evaluated. Finally, fibre transmission was demonstrated at 1.8 Gb/s over 310.3 km with a 62 dB repeater gain in a direct detection repeater system.

System performance of optical fibre preamplifier

An optical fibre amplifier has been used as an optical preamplifier for a pin detector-based receiver. A maximum amplifier gain of 22 dB has been measured and, at this gain with no additional optical filtering, an improvement of 10.5 dB in receiver sensitivity has been achieved.