The use of frequency-shifted feedback (FSF) lasers in optical metrology is based on a unique coherence property: the appearance of beats in the noise spectrum at the output of a two-beam interferometer, whose frequencies vary linearly with the path delay of the interferometer. A description of the output of a FSF laser as a moving comb of optical frequencies is generally admitted to explain these specific coherence properties. Here starting from the model of a passive FSF cavity seeded by spontaneous emission we give a rigorous description of the time-spectrum properties of FSF lasers and show that the moving comb exists only in the limit of small frequency shift. © 2011 Elsevier B.V. All rights reserved.
Guillet De Chatellus, H., Lacot, E., Glastre, W., Jacquin, O., & Hugon, O. (2011). The hypothesis of the moving comb in frequency shifted feedback lasers. Optics Communications, 284(20), 4965–4970. https://doi.org/10.1016/j.optcom.2011.06.042