A Wide Pull Range Hybrid VCSO For Optical Transmission Networks

The new optical network standard, SONET (Synchronous Optical Network), requires a high performance, low-cost VCO at the line rate of 622.08 Mb/s. A SAW resonator-based VCO was designed to meet these requirements. It contains a hybrid integrated circuit with a small number of readily available discrete components and a quartz SAW resonator. Traditionally, a SAW delay line has been used to obtain a wide tuning range with an associated penalty in noise performance. The VCSO circuit design makes a wide tuning range possible with good noise performance.