We have recently described a wavelength-recognizing switch (WRS) which we showed to be capable of truly all-optical routing. Although other authors had previously reported "all-optical" networks [1, 2, 3], the term has generally referred to all—optical data paths only. In such implementations only the data remains in optical format as it propagates along the network paths. Optical-to-electronic conversions are still allowed for what is termed "control signals," namely address bits and additional signaling entities, which are assumed to have lower speed than the data. In contrast, the WRS we presented has the capability to route data by interpreting the control signals in the optical domain, thus avoiding the overhead and the latency ofthe optic-to-electronic conversion. In a series of previous publications [4, 5] we demonstrated the experimental viability of the WRS and measured some of the relevant system parameters of the device. More recently, we published details on how the device could be used to build multistage all-optical self-routing networks. We also developed a simulation model and estimated the maximum number of stages that can be cascaded in such networks. The work presented in this paper carries the simulation results one step further, and investigates some of the possible topologies that can be used for WRS networks, as well as the system implications of these topologies. To facilitate a better understanding of the concepts presented, we briefly review the device functionality and the main experimental results that affect the system performance. We then show how to implement some of the building blocks we use in the self-routing topologies, and explain the equalization mechanism necessary for using WRS in multistage networks. We then compare the practical advantages of the topologies of interest and decide which topology is the most probable implementation. Finally we present details on a new generation of WRS, which is waveguide based, thus more easily fabricated and integrated with optical fiber systems
High quality traveling-wave semiconductor optical amplifiers were designed and fabricated for all-optical switching applications. We obtained 21 dB small signal gain with 0.16 dB gain ripple. Measured residual reflectivity was 5 X 10<SUP>-5</SUP> and the 3-dB gain bandwidth as wide as 70 nm. Our results show careful wavelength selection is required in order to match the amplifiers gain peak wavelength to the desired operating wavelength of the optical switches.
We investigated differential gain, refractive index and (alpha) -parameter in strongly index and gain guided broad- area semiconductor optical amplifiers. The measured linewidth enhancement factor is larger than the values reported for narrow-stripe lasers and is consistent with theoretical predictions.