Novel two-stage wavelength-routed access architecture employing spectral-grooming and replicated arrayed waveguide gratings

Wavelength-routing is becoming increasingly attractive for ATM optical access networks as it can offer improved power compared with splitter architectures. Arrayed waveguide gratings (AWGs) and their periodic properties have been exploited within access architectures capable of delivering multiple services with increased privacy, reduced crosstalk, and built-in upgradability. We develop the AWG concept by proposing a two-stage access architecture based on cascaded fine- and coarse-wavelength demultiplexers, where the free spectral range (FSR) of the fine AWG matches the passband period of the coarse AWG. With a conservative simulation, we show that using a 4 nm FSR, a channel spacing of 0.27 nm and with optical crosstalk better than -13 dB, a minimum of 100 users can be addressed with multi-gigabit information. Additional benefits offered by the architecture include relaxed sensitivity to component variation, commonality in coarse demultiplexer specification and potentially lower crosstalk.