Paul Gabla

401 km, 622 Mb/s and 357 km, 2.488 Gb/s IM/DD repeaterless transmission experiments using erbium-doped fiber amplifiers and error correcting code

Record repeaterless transmission distances of 401 km at 622 Mb/s and 357 km at 2.488 Gb/s on nondispersion-shifted fiber are demonstrated. The transmission format is intensity modulation/direct detection (IM/DD), and a forward error correcting code scheme is implemented. Erbium-doped fiber amplifiers are used at the transmit and receive end of the system as postamplifier, preamplifier, and remotely pumped amplifier. >

35 AM-VSB TV channels distribution with high signal quality using a 1480 nm diode-pumped erbium-doped fiber postamplifier

In the system considered, the postamplifier, with an output power of +9.6 dBm, did not degrade the very high linearity of the isolated distributed-feedback (DFB) laser transmitter. A 51.2-dB weighted signal-to-noise ratio was obtained, and an optical power budget of 16 dB was achieved with a weighted signal-to-noise ratio higher than 48 dB. A larger power budget with a higher signal-to-noise ratio (SNR) is possible with an increase of DFB laser output power and erbium-doped fiber amplifier (EDFA) saturated output power, and with a minimization of the EDFA noise contribution.<<ETX>>

1111 km, two channel IM-DD transmission experiment at 2.5 Gb/s through 21 in-line erbium-doped fiber amplifiers

Two-channel transmission is demonstrated in a 2.5 Gb/s intensity-modulated direct-detection system over a distance of 1111 km, using 21 in-line erbium-doped fiber amplifiers. The two channels incur virtually no penalty when they are transmitted simultaneously. Owing to the use of gain filtering in the amplifiers instead of discrete in-line optical filters, the overall bandwidth of the link is about 15 nm, for a sensitivity penalty smaller than 1 dB on one single transmitted channel.<<ETX>>

Practical implementation of a highly sensitive receiver using an erbium-doped fiber preamplifier

A practical erbium-doped fiber preamplified direct detection receiver is demonstrated with which receiver input sensitivities of -46.5 dBm at 622 Mb/s and -40.7 dBm at 2.3 Gb/s have been achieved. There is no penalty from the transmission fiber Rayleigh backscattering. The bit error ratio measurements with 2/sup 23/-1 NRZ PRBS (pseudorandom bit sequence) show highly stable characteristics with no apparent error floor, owing to the polarization insensitivity of the preamplifier and to an active locking of the receiver optical filter. The tradeoff between preamplifier and avalanche gain is shown, and the influence of optical filter bandwidth and decision threshold setting is measured.<<ETX>>

279 km, 591 Mb/s direct detection transmission experiment using four in-line semiconductor optical amplifiers

The authors realized a direct detection intensity-modulation system experiment with four cascaded in-line semiconductor optical amplifiers. Using optical isolators between the amplifiers, they transmitted a NRZ 2/sup 23/-1 message over a distance of 279 km at a bit rate of 591.2 Mb/s. A comparison of this result with parallel experiments without optical isolators indicates that for a realistic implementation of long distance systems with semiconductor optical amplifiers, interamplifier optical isolators will be needed unless the residual facet reflectivity of the optical amplifiers is brought to a very low value (<1*10/sup -4/).<<ETX>>

407-km, 2.5-Gbit/s repeaterless transmission using an electroabsorption modulator and remotely pumped erbium-doped fiber post- and pre-amplifiers

Using an integrated laser/electroabsorption modulator transmitter, a remotely pumped postamplifier and a remotely, pumped preamplifier, a repeaterless transmission distance of 407 km over nondispersion shifted fiber is achieved at 2.5 Gbit/s. This experiment takes full advantage of high power 1480 nm pump laser diode modules through optimized remote pumping configurations and benefits from the good behavior of the electroabsorption modulator transmitted waveform in presence of fiber nonlinearity and chromatic dispersion.<<ETX>>

Bright prospects for erbium-doped fiber amplifiers in future lightwave communication systems

Abstract In the light of achievable component performance from both a theoretical and an experimental point of view, the applications of erbium-doped fiber amplifiers (EDFA) in long distance repeaterless digital transmission and analog cable TV distribution is discussed. In digital repeaterless systems, EDFA postamplifiers are capable of output powers over + 15 dBm; preamplifiers and remotely pumped amplifiers improve system budgets by more than 7 dB and 13 dB, respectively, when compared to a conventional APD (avalanche photodiode) receiver. In analog AM-VSB TV distribution networks, EDFA postamplifiers improve the power budget by more than 10 dB, and cascaded EDFA repeaters hold promise for power budgets over 35 dB, allowing large splitting ratios in the network.