An optoelectronic clock recovery circuit using a resonant tunneling diode and a uni-traveling-carrier photodiode

A clock recovery circuit is a key component in optical communication system s. In this paper, an optoelectronic clock recovery circuit is reported that monolithically integrates a resonant tunneling diode (RTD) and a uni-trave ling-carrier photodiode (UTC-PD). The circuit is an injection-locked-type R TD oscillator that uses the photo-current generated by the UTC-PD. Fundamen tal and sub-harmonic clock extraction is confirmed for the first time with good clock recovery circuit characteristics. The IC extracts an electrical 11.55-GHz clock signal from 11.55-Gbit/s RZ optical data streams with the w ide locking range of 450 MHz and low power dissipation of 1.3 mW. Furthermo re, the extraction of a sub-harmonic clock from 23.1-Gbit/s and 46.2-Gbit/s input data streams is also confirmed in the wider locking range of 600 MHz . The RMS jitter as determined from a single sideband phase noise measureme nt is extremely low at less than 200 fs in both cases of clock and sub-harm onic clock extraction. To our knowledge, the product of the output power an d operating frequency of the circuit is the highest ever reported for injec tion-locked-type RTD oscillators. These characteristics indicate the feasib ility of the optoelectronic clock recovery circuit for use in future ultra- high-speed fully monolithic receivers.