Abstract: The encoder/decoder design for spectrum-encoded optical CDMA systems uses waveguide circuits monolithically integrated on one chip to fulfill essential encoding and decoding functions. The integrated device functions as a 1×2 wavelength selective Mach-Zehnder interferometer switch to encode the input broadband light source and to decode the transmitted spectrally encoded signals. The device comprises a frontal 3-dB coupler, a double-ended arrayed-waveguide grating (AWG), and arrays of thermooptic phase shifters and attenuators, together with their symmetric images reflected from the high-reflection coated facet, to realize all required functionality. The thermooptic phase shifters and attenuators are programmable through electronic interface to realize programmable encoding and decoding capabilities. The attenuators are used to equalize the powers and to increase the ON/OFF extinction ratio of all spectral chips.

Abstract: An optical cross-connect for the switching of optical channels at variable bit-rate (up to 10 Gbit/s), wavelength division multiplexed on bi-directional optical fibers forming the transmission backbone of a transport network; in particular the cross-connect can be interfaced to fibers crossing the nodes of a ring having large territorial extension, provided with protection fibers. The cross-connect includes a spatial Split & Select input stage of WDM aggregates, followed by a set of channel filters tunable on the whole optical range occupied by the channels, which jointly form a structure strictly not blocking the access to the channels by a set of bridge units whose functionality is selectable on a per-channel basis, such as for instance: transit, drop/insert, regeneration, etc. An output optical spatial Split & Select stage connects in a strictly non-blocking way the single channels from bridge units to optical multiplexers that reconstruct the WDM aggregate on the output fibers.