Fast Remotely Reconfigurable Wavelength Selective Switch A. Rohit, A. Albores-Mejia, N. Calabretta, X. J. M. Leijtens, D. J. Robbins, M. K. Smit and K. A. Williams COBRA Research Institute, Eindhoven University of Technology, PO. Box 512, 5600MB – Eindhoven, The Netherlands a.rohit@tue.nl Abstract: A remotely reconfigurable wavelength selective switch is proposed which implements label detection and signal gating in the same SOA array. A proof of principle monolithic circuit is presented showing dynamic nanosecond label-controlled switching. OCIS codes: (250.5300) Photonic integrated circuits; (250.6715) Switching; (130.7408) Wavelength filtering 1. Introduction Fast wavelength selector switches (WSS) and tuneable filters are an increasingly important enabling technology for efficient, next-generation, WDM networking. Monolithically integrated designs based on arrayed waveguide gratings (AWG) and semiconductor optical amplifiers (SOA) have been demonstrated with increasingly impressive levels of connectivity [1,2]. Multi-wavelength optical labels have been proposed to reconfigure such WSS sub- systems for packet-switched applications [3,4,5]. Binary WDM coding offers the prospect of on-the-fly routing, minimised network delay and the avoidance on clock recovery at the optical switch element [6]. The approach is additionally scalable as a minimum of n optical labels can control 2 n WDM channels. However many of the WSS solutions proposed to date assume separate circuit elements for the monitoring of label multiplexes and the routing of data. The additional components and splitters incur hardware complexity, energy loss and link loss. On-chip label detection has been studied for switching matrices to simplify hardware complexity [7], although the implemented scheme does still require additional monitors for full circuit operation. In this work we propose a wavelength flexible monolithic scheme for fast nanosecond-speed, on-the-fly reconfiguration using monolithically integrated label readers and channel selectors. The concept uses a dual function SOA array to both detect labels and gate routed signals. A proof of principle experimental demonstration is described for a monolithically integrated photonic integrated WSS. We present comparative bit error rate measurements for performance with and without dynamically reallocated switching states. 2. Wavelength Selective Switch Architecture The proposed architecture of the WSS node is shown in figure 1 with the test arrangement. Control channels are multiplexed with the data channels to allow parallel processing of labels and data. The arrayed waveguide cyclic router separates the labels from the data and uses label derived information to define the switch state. The designation as detector SOA and gating SOA is defined exclusively by the electronic driver circuits: the photonic connections and designs for the SOAs are identical. The outputs from the gate array are combined with another wavelength multiplexer or potentially more flexibly with a power combiner. In this study we consider the latter. The full implementation would additionally call for additional as-yet-unimplemented channel insertion. SOA Electronic Subsystem SOA SOA n 2 n Control re-write* Transmitter . . . . . . . . 10 Gbit/s Data Transmitter Transmitter n Label Test input Wavelength selective switch node Test output . . . . . . . . Amplified and filtered Receiver OSC. BERT *Control re-write node not implemented Figure 1. The wavelength selective switch concept and experimental arrangement. The output of the cyclic router is gated in the wavelength domain with a semiconductor optical amplifier (SOA) gate array prior to recombining the signals. OTuM1.pdf OSA/OFC/NFOEC 2011 OTuM1.pdf