An Endless Optical Phase Delay for Phase Synchronization in High-Capacity DCIs

TL;DR

This paper introduces an endless optical phase delay module that provides continuous, reset-free phase adjustment for optical signals, demonstrated experimentally for high-capacity data center interconnects and potentially useful in various real-time phase control applications.

Contribution

We propose and experimentally demonstrate a novel endless optical phase delay module using an IQ modulator and control electronics with a gradient descent algorithm for real-time phase adjustments.

Findings

Successfully demonstrated continuous phase delay in experiments.

Applicable to high-capacity data center interconnects.

Potential for broader applications in phase/frequency control.

Abstract

In this work, we propose and demonstrate a module to linearly add an arbitrary amount of continuous (reset-free) phase delay to an optical signal. The proposed endless optical phase delay (EOPD) uses an optical IQ modulator and control electronics (CE) to add the desired amount of phase delay that can continuously increase with time. In order to adjust for the bias voltages and control voltage amplitudes in the EOPD, some of which may be time varying, a multivariate gradient descent algorithm is used. The EOPD has been demonstrated experimentally, and its use in a high-capacity data center interconnect (DCI) application has been outlined in this letter. The EOPD may find its use in many other applications that require precise phase/frequency adjustments in real-time.