Multi-Gb/s silicon bipolar clock recovery IC

A novel clock recovery IC for optical fiber communication systems with data rates up to several Gb/s is presented. It combines nonlinear signal preprocessing directly with a regenerative frequency divider scheme and an external filter in the divider loop. Hence, the center frequency of the filter and the working frequency of the amplifier are halved. The extracted clock frequency corresponds to half the bit rate, as required for many clocked circuit components within fiber optic lines. Two versions of the same IC design, scheduled for two bit rate ranges between 0.3-4 Gb/s, are realized with a conventional Si bipolar process. Clock recovery is demonstrated at 2.2 and 3.52 Gb/s, using both cavity and surface acoustic wave (SAW) filters