Achieving High Absolute Accuracy for Group-Delay Measurements Using the Modulation Phase-Shift Technique

Published

November 1, 2005

Author(s)

Tasshi Dennis, Paul A. Williams

Abstract

We have developed a modulation phase shift (MPS)system for measuring relative group delay (RGD)in optical components with high absolute accuracy and simultaneously high temporal and wavelength resolution. Our 200-MHz system has a 3.2-pm wavelength resolution and has demonstrated a group-delay resolution of 0.072 ps for repeated measurements of an artifact based on a hydrogen-cyanide gas cell. The expanded uncertainty (k = 2)is ±0.46 ps for a single spectral measurement ( 3.4-pm steps) of a narrow 20-ps group-delay feature of the artifact. To our knowledge, this is the first time that the sources of measurement uncertainty for this technique have been described and quantified. A method for predicting the group delay of the gas-cell artifact from measured absorption spectra is described, and an uncertainty analysis for the prediction method is also presented. The implementation required to achieve results of the highest accuracy for both measurements and predictions is discussed.

Citation

Journal of Lightwave Technology

Volume

23

Issue

11

Pub Type

Journals

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Keywords

Calibration, Group Delay, Laser, Optical Fiber, Phase Shift, Telecommunications, Uncertainty Analysis

Citation

Dennis, T. and Williams, P. (2005), Achieving High Absolute Accuracy for Group-Delay Measurements Using the Modulation Phase-Shift Technique, Journal of Lightwave Technology, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=31806 (Accessed October 21, 2025)