Search

We report on the 1O-Gb/s operation of the reflective semiconductor optical amplifier (RSOA) for the next-generation wavelength-division-multiplexed passive optical network (WDM PON). The bandwidth of the RSOA used in this experiment is merely 2.2 GHz. Nevertheless, a clear eye opening is obtained at 10 Gb/s by using the electronic equalizer processed offline. We investigate the impacts of the network's operating conditions (such as the injection power to the RSOA and the fiber length) on the performances of these equalizers. The results show that the RSOA-based WDM PON is operable at 10 Gb/s and the maximum reach can be extended to >20 km with the help of the forward error correction codes. [ABSTRACT FROM PUBLISHER]

We report on the operable ranges of temperature and wavelength for a 1.25-Gb/s wavelength-division-multiplexed passive optical network (WDM PON) implemented by using uncooled reflective semiconductor optical amplifiers (RSOAs). Both the gain and modulation bandwidth of the RSOA are substantially reduced at high temperatures. As a result, it is difficult to achieve the error- free operation at temperatures above 40degC. In order to mitigate this limitation, we implement a simple bias-control circuit, in which the bias current is controlled stepwise according to the operating temperature of the RSOA. Using this circuit, we extend the operable wavelength range of the RSOA-based WDM PON to ~55 nm in the temperature range of -20degC to 60degC. [ABSTRACT FROM PUBLISHER]

We describe a new method for monitoring the ldquoin-bandrdquo optical signal-to-noise ratio (OSNR) of differential phase-shift-keying (DPSK) and differential quadrature phase-shift-keying (DQPSK) signals. This technique estimates the OSNR by analyzing the radio frequency spectrum obtained by the self-heterodyne detection. The results show that the performance of the proposed technique is not sensitive to the effects of chromatic dispersion and polarization-mode dispersion. In addition, this technique can be used for monitoring the polarization-scrambled signals. For a demonstration, we measure the OSNR of the polarization-scrambled 10-Gb/s DPSK and 20-Gb/s DQPSK signals in a 640-km-long transmission link. [ABSTRACT FROM PUBLISHER]

To evaluate the effectiveness of the pilot-tone-based monitoring technique in differential phase-shift keying (DPSK) systems, we measure the mutual interactions between the pilot tones and DPSK signals and compare the results with those of on-off keying (OOK) signals. The results show that, by using the DPSK format instead of OOK, it is possible to increase the number of wavelength-division-multiplexed channels that can be monitored simultaneously by using pilot tones without using optical demultiplexers by more than one hundred times [ABSTRACT FROM PUBLISHER]

We have investigated the effect of temperature variation on the performance of fiber-based optical phase conjugation (OPC) module. The results show that the bandwidth of the fiber-based OPC module could be reduced significantly by temperature variation. However, it would be difficult to control the temperature of bulky fiber spool precisely. To solve this problem, we have proposed and demonstrated a simple method to compensate the bandwidth reduction (caused by temperature variation) by adjusting the pump power. Using this method, we could maintain the 1-dB bandwidth of fiber-based OPC module within 5% even when the ambient temperature was varied as much as plusmn15 degC [ABSTRACT FROM PUBLISHER]

We report on the effect of the partially polarized amplified spontaneous emission noise on the Q-factor estimation by using optical signal-to-noise ratio. The result shows that this effect is negligible even in a long-distance transmission system (number of spans: <40) as long as the polarization-dependent loss per span is smaller than 0.2 dB [ABSTRACT FROM PUBLISHER]

The implemented a bidirectional erbium-doped fiber amplifier using two spectrally interleaved synchronized etalon filters. This amplifier was used to demonstrate 2.5 Gb/s×16 channel bidirectional wavelength-division-multiplexed (WDM) transmission over 160-km-long single mode fiber. No power penalty was observed in receiver sensitivity caused by relative intensity noise. In addition, we measured the performance of the concatenated amplifiers using a recirculating loop. The results show that it would be possible to use the proposed amplifier for the transmission of bidirectional WDM signals over seven amplifier spans (~560 km) with a span loss of 20 dB [ABSTRACT FROM PUBLISHER]

We demonstrate a directly modulated 2.5 Gb/s×16 channel wavelength-division-multiplexed (WDM) transmission system over 640 km of conventional single-mode fiber using the dispersion compensating fiber. The capacity of this system could be increased easily without adjusting the outside plant by replacing the directly modulated 2.5-Gb/s channels with the externally modulated 10-Gb/s channels. To demonstrate the feasibility of this capacity upgrade, we implement a 130-Gb/s (10 Gb/s×12 channels+2.5 Gh/s×4 channels) WDM transmission system using the same fiber-optic link [ABSTRACT FROM PUBLISHER]