Low temperature spectrum of a fiber loop laser

TL;DR

This paper investigates how the optical spectrum of an Erbium-doped fiber loop laser changes at low temperatures, revealing narrow peaks and a potential link to prime numbers, with implications for telecommunication and meteorology.

Contribution

It provides the first experimental analysis of low-temperature effects on fiber loop laser spectra and explores the hypothesis of intermode coupling causing comb formation.

Findings

Narrow, unequally-spaced spectral peaks appear below 10 K.

A possible connection between peak wavelengths and prime numbers is discussed.

Spectral behavior is linked to intermode coupling hypothesis.

Abstract

Fiber-based multi-wavelength lasers have a variety of important applications in telecommunication and meteorology. We experimentally study a fiber loop laser with an integrated Erbium doped fiber (EDF). The output optical spectrum is measured as a function of the EDF temperature. We find that below a critical temperature of about $10\unit{% K}$ the measured optical spectrum exhibits a sequence of narrow and unequally-spaced peaks. An intriguing connection between the peaks' wavelengths and the sequence of prime numbers is discussed. An hypothesis, which attributes the comb formation to intermode coupling, is explored.