# 103-Gb/s long-reach WDM PON implemented by using directly modulated RSOAs

ArticleinIEEE Photonics Technology Letters 24(3):209-211 · February 2012with 28 Reads
Abstract
We propose and demonstrate a long-reach wave- length-division-multiplexed passive optical network (WDM PON) capable of providing 100-Gb/s service to each subscriber, for the first time to the best of our knowledge. For cost-effectiveness, this network is implemented in loopback configuration by using directly modulated reflective semiconductor optical amplifiers (RSOAs) at 25.78 Gb/s. For the modulation of the RSOA at such a high-speed, we have to minimize the electrical parasitics by using the butterfly package. Also, to overcome the limited bandwidth of the RSOA, we utilize the electronic equalization technique at the receiver. We use four RSOAs at each optical network unit for the 103-Gb/s upstream transmission. The operating wavelengths of these RSOAs are separated by the free-spectral range of the cyclic arrayed waveguide gratings used at the central office and remote node (RN) for (de)multiplexing the WDM channels. We extend the maximum reach of this WDM PON to be ${>}{\rm 120}~{\rm km}$ by using Erbium-doped fiber amplifiers at the RN. The results show that the error-free transmission can be achieved for all WDM channels in the wavelength range of ${>}{\rm 35}~{\rm nm}$ with sufficient power margins.
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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.
• Article
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.
• Article
We use a novel fiber-grating device to demonstrate the first polarization-insensitive all-fiber higher order mode dispersion compensator for broad-band dispersion compensation. Its low loss and high effective area have enabled transmission through 1000 km (10/spl times/100 km) of nonzero dispersion-shifted fiber (NZDSF) at 40 Gb/s.
• Article
The measurement of intermodulation distortion (IMD) induced by carrier-density modulation in a multiple-quantum-well (MQW) semiconductor amplifier is reported. The results show that MQW amplifiers have 15 dB less IMD than conventional buried-heterostructure semiconductor amplifiers. The IMD is dependent on the output power of the amplifiers, which confirms that the carrier-density modulation is the dominant nonlinear mechanism in MQW amplifiers. In addition, the results show that, unlike conventional buried-heterostructure amplifiers, MQW amplifiers have at least two time constants (200-250 ps and <10 ps) for the gain recovery process.< >