Abstract

Optical time-division multiplexing (TDM) techniques increase the information capacity of digital optical communication systems. Acoustooptic (AO) deflectors or scanners (using linear FM drive signal) were proposed for TD demultiplexing. The allowable instantaneous data rate to be demultiplexed is R_i = N/T_c = τ Δf/T_c, where N is the number of resolvable points, τ is the AO aperture time, Δf is the frequency sweep bandwidth, and T_c is the sweep time. Since the AO deflector needs to be blanked for time τ each sweep time T_c, the maximum average data rate will be R_a = Δf/4, when τ = T_c/2. To increase the data rate, we propose a new architecture using two AO cells which enable us to achieve an average data rate twice that of the above described system. This system will use an electrooptic switch to illuminate the AO cells alternatively. The data rate is limited by the bandwidth Δf, and the sweep rate. To overcome the bandwidth limitation, we propose to use the acousto-electro-optic effect to compensate for the phase mismatch (from frequency deviation) which results in increasing the bandwidth of the AO cell. The proposed processor will be capable of operating on data rates of tens of GHz. Also this processor will enable the TD demultiplexing to be performed on the light beam as it emerges from the fiber without the need to convert the optical signal to electronic one, which tends to slow down the process.

© 1991 Optical Society of America