The implementation of timing recovery circuits in multigigabit/s optical regenerators becomes increasingly difficult because of the complexity of nonlinear circuit elements at such high data rates. We propose and demonstrate a new method of data regeneration without nonlinear retiming circuits. In the proposed scheme, the clock is superimposed on the data signal at the transmitter end and is separated from the composite signal at the receiver end by means of a novel microstrip directional filter for data regeneration. This scheme offers significant reduction in circuit complexity over conventional regenerator designs and has less pattern dependence and systematic jitter since the clock is not derived from the baseband data. A compact regenerator at 2.4 Gbit/s has been implemented using this technique and transmission over 35 km of dispersion-shifted fiber (DSF) with a 1550-nm DFB laser has been demonstrated.
© 1989 Optical Society of AmericaPDF Article