Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Fiber-laser frequency combs with subhertz relative linewidths



William C. Swann, John J. McFerran, Ian R. Coddington, Nathan R. Newbury, Ingmar Hartl, Martin E. Fermann, Paul S. Westbrook, Jeffrey W. Nicholson, K Feder, Carston Langrock, Martin M. Fejer


We investigate the comb linewidths of self-referenced, fiber-laser-based frequency combs by measuring the heterodyne beat signal between two independent frequency combs that are phase locked to a common cw optical reference. We demonstrate that the optical comb lines can exhibit instrument-limited, subhertz relative linewidths across the comb spectra from 1200 to 1720 nm with a residual integrated optical phase jitter of 1 rad in a 60 mHz to 500 kHz bandwidth. The projected relative pulse timing jitter is 1 fs. This performance approaches that of Ti:sapphire frequency combs.
Optics Letters


Fiber laser frequency combs, narrow linewidth lasers


Swann, W. , McFerran, J. , Coddington, I. , Newbury, N. , Hartl, I. , Fermann, M. , Westbrook, P. , Nicholson, J. , Feder, K. , Langrock, C. and Fejer, M. (2006), Fiber-laser frequency combs with subhertz relative linewidths, Optics Letters, [online], (Accessed March 1, 2024)
Created October 14, 2006, Updated October 12, 2021