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 systems. In this paper, an optoelectronic clock recovery circuit is reported that monolithically integrates a resonant tunneling diode (RTD) and a uni-traveling-carrier photodiode (UTC-PD). The circuit is an injection-locked-type RTD oscillator that uses the photo-current generated by the UTC-PD. Fundamental 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 11.55Gbit/s RZ optical data streams with the wide locking range of 450MHz and low power dissipation of 1.3mW. Furthermore, the extraction of a sub-harmonic clock from 23.1-Gbit/s and 46.2Gbit/s input data streams is also confirmed in the wider locking range of 600MHz. The RMS jitter as determined from a single sideband phase noise measurement is extremely low at less than 200 fs in both cases of clock and sub-harmonic clock extraction. To our knowledge, the product of the output power and operating frequency of the circuit is the highest ever reported for injectionlocked-type RTD oscillators. These characteristics indicate the feasibility of the optoelectronic clock recovery circuit for use in future ultra-high-speed fully monolithic receivers. key words: optoelectronic integrated circuit, clock recovery cir-