OOK Q-factor degradation in scalable optical switches

Abstract

All-optical switching has been proposed to overcome the limitations of electronic switches in terms of scalability, speed, footprint, and power consumption. A key passive optical component to bypass electronic processing limitations is the arrayed waveguide grating (AWG). Switch architectures combining wavelength converters and fiber delay lines provide tunable routing and contention resolution when used with AWGs. An AWG passively routes either single or multiple input port wavelengths to its output ports. A single wavelength per port strategy reduces crosstalk within the AWG, but drastically increases the dimensionality of the device. Physical constraints on AWG design limit the port number for the foreseeable future to under 100. To scale optical switches to emerging network requirements, we can use multiple wavelengths per port. In this paper we examine one multiple wavelength per port architecture and quantify the physical layer impairments due not only to the AWG crosstalk, but also Q-factor degradation due to multiple wavelength conversions, and as a function of the number of recirculations in the contention resolution delay lines. While previous work has addressed this issue in terms of accumulated loss, we focus on accumulated relative intensity noise and amplified spontaneous emission.