It is desirable for data networks to have low transmission latency. This may be achieved by exploiting the short packet lengths and the high bandwidths that can be achieved using multi-wavelength operation. Semiconductor optical amplifiers (SOAs) have been demonstrated as building blocks for optical switches and have also been shown to be well suited to the fast switching required for optical packet switching . We have realised an InP based add-drop multiplexer (ADM) integrated on a single 850 μm x 850 μm chip. The bit error penalty performance has previously been shown to be below 1.2 dB for each of the operating paths through the device: add, drop and through modes at 2.5 Gbit/s data rates. Further, low penalty operation has previously been demonstrated experimentally with 4 simultaneous wavelengths .
It is known that the dynamic range of an SOA can limit the number of wavelengths supported and that the pattern sensitivity in SOAs increases their operating penalty . We investigate the multi-wavelength operation of our ADM device and show that a power penalty of less than 0.8 dB is maintained over a 20 dB input power dynamic range. We also show a -3 dB optical bandwidth of 30 nm suitable for multi-wavelength operation of cascaded ADMs. Finally we present experimental results to show that the pattern dependent operating penalty of the ADM is reduced as the number of wavelengths of asynchronous data is increased. This result may be exploited in our proposed optical data network to produce an improved optical penalty.
Proc. SPIE. 5248, Semiconductor Optoelectronic Devices for Lightwave Communication
KEYWORDS: Switches, Coarse wavelength division multiplexing, Switching, Waveguides, Networks, Wavelength division multiplexing, Control systems, Telecommunications, Local area networks, Standards development
This paper describes the current status of Coarse Wavelength Division Multiplexing (CWDM), and then progresses to discuss how it may evolve in networking applications in the future. As WDM can enhance not only transmission but also networking systems, the paper reports a potentially low cost WDM based access node architecture, particularly suited for routing optical data packets on nanosecond timescales. The scheme is cascadable and involves the use of a simple semiconductor optical amplifier (SAO) based add-drop switch. Preliminary results concerning the operation of the add-drop switches under multi-wavelength operation are reported.