InP-HBT optoelectronic integrated circuits for photonic analog-to-digital conversion

A monolithically integrated optical receiver and a 4-bit flash analog-to-di gital converter, all in InP HBT technology, have been implemented. The opti cal receiver converts an incoming optical pulse train into an electronic si gnal and is functional up to 10 Gsps. The electronic input 4-bit flash ADC achieves 3.8 effective bits at low input frequency and 2.1 effective bits a t Nyquist input frequency when sampled at 10 Gsps. A 3-bit version has 2.8 effective bits at low-input frequency and 2.4 effective bits at Nyquist-inp ut frequency when sampled at 10 Gsps. The 3-bit ADC operates up to 18 Gsps where it has 1.7 effective bits at Nyquist-input frequency.