High frequency optoelectronic pulse source for digital communications

Clocks and pulse sources are critical elements for next generation IC¿¿s such as DSP¿¿s and ¿Yprocessors which depend critically on stability and jitter. Clock skew becomes significant because of the large chip dimension. ADC¿¿s and DAC¿¿s are mixedsignal circuits which demand extremely precise clocks at multi GB/s rates. Telecommunication transceivers and transponders at 40 GB/s require phase-locked-loops with fs jitter control. Digital radar requires pulse sequences with fixed pulse width andcontrollable duty cycle. The stable, low jitter pulse source is the key. We propose a novel pulse source built around an optoelectronic thyristor integrated monolithically with HFETs in a GaAs technology. As both a laser and a thresholding detector, itimplements an oscillator which is optically triggered after a fixed optical path delay. The delay sets the duty cycle and for each optical switching event, an electrical pulse is generated of up to 15V with a width of 1 ¿V 10ps. The path delay and thuspulse spacing are uniquely controlled by HFET logic activating directional couplers which are also integrated. The pulses are guided by transmission line to a integrated dipole antenna element at the chip edge. In this STTR, we will develop the integratedpulse source technology. The integrated OEIC technology has diverse applications in both military and space data processing. Applications include 2D parallel signal processing, read and write optical memories, transceivers, high speed optical switching andoptical computing. While addressing current application needs for low cost integrated components it also defines a large number of new markets.