Phase-stable broadband remote receiving system based on a dithered sample clock

Abstract

We present a phase-stable receiving system for signals transmitted via a 25 km fiber optic link. The timing jitter of the signal induced by the transmission link is precisely eliminated after the signal is digitized with a dithered sample clock. The dithered clock is generated from the phase of a voltage-controlled oscillator, introducing the same transmission timing jitter of the link. Therefore, it can withstand an unlimited range of transmission delay variations without using any optical or electrical delay lines. Experimentally, a binary phase-shift keying signal is transmitted and received by the proposed system. The calculated timing jitter of the received signal with a bandwidth of 400 MHz is decreased from 650 ps to merely 1.6 ps. The simple remote end and immunity to environmental perturbations of the proposed scheme make it an ideal candidate for a large-scale distributed antenna system.