Architectures and performance of awg-based optical switching nodes for ip networks

Abstract

In order to support the continuous growth of transmission capacity demand, optical packet switching technology is emerging as a strong candidate, promising to allow fast dynamic allocation of WDM channels, combined with a high degree of statistical resource sharing. This work addresses the design of optical switch architectures, based on previous proposals available in the technical literature that use an arrayed waveguide grating (AWG) device to route packets. Since the port number of currently available AWGs is a limiting factor, we propose two new modified structures which better exploit the switching capability of this component in the wavelength domain.Since a limited hardware complexity is a key requirement for all-optical switches, due to the high cost of optical components, these different node configurations are compared in terms of complexity. Traffic performance of these new structures in a full optical packet switching scenario is also examined.

Studies on a Class of AWG-Based Node Architectures for Optical Burst-Switched Networks

“…In OBS nodes, similar issues become relevant, and the switching scheme proposed earlier in [3] using wavelength converters and SOAs offer strictly-nonblocking performance but with a high hardware complexity, and also suffer from lower reliability due to the use of large number of active devices such as tunable wavelength converters (TWCs) and SOAs. More recent switching schemes for OBS nodes [4]- [6] adopt simpler optical hardware using AWGs along with TWCs, however with limited internal blocking. In the following section, we propose a class of AWG-based node architecture, albeit with novel improvisations, which reduce internal blocking but with a significantly less optical hardware for OBS routing.…”

“…However, the hardware complexity in such configurations has motivated other research groups to explore alternative node architectures that can offer simple and fast operation, however with a limited blocking in the switch fabric in some configurations. Most of these node architectures make use of TWCs along with arrayed-waveguide grating (AWG) as the basic switching hardware, the latter offering a static wavelength-selective routing functionality between its input and output ports [4]- [6]. In particular, AWG is a passive static device which is wavelength sensitive.…”

“…This type of switching scheme is attractive because it reduces network cost and complexity, and simplifies network management, as compared to the network architectures employing a large number of SOAs for switching purpose. Furthermore, because of its passive nature, AWG is a highly-reliable device without any power consumption and also offers lower insertion loss than a normal space switch [6].…”

Performance of optical packet switching nodes in IP transport networks

“…Supposing a bit rate of 10 Gbit/s per wavelength channel, a 40 ns slot duration seems appropriate, since the 40-bytes payload is transmitted in 32 ns, and the additional time can be used for the optical packet header transmission and to provide guard times. For a deeper discussion about this issue the reader is referred to [3].…”

“…In particular it considers the architecture of optical packet switching nodes already proposed in [1][2] [3], which exploit arrayed waveguide grating devices for packet routing and are equipped with fiber delay lines used either for input buffering or for shared buffering of optical packets. The paper is organized as follows.…”