Limitations due to residual interference in a fiber-based optical frequency reference at 1.55 $\mu$m

TL;DR

This paper investigates how residual interference from fiber-optic components limits the frequency stability of fiber-based optical frequency references at 1.55 μm, highlighting the impact of fiber-induced reflections on stability.

Contribution

It provides an experimental analysis of interference effects in fiber-optic frequency standards and identifies the main sources limiting stability in such systems.

Findings

Interference fringes due to fiber components limit stability to 10^-13.

Temperature and power fluctuations influence interference effects.

Residual reflections significantly constrain high-precision fiber-optic frequency references.

Abstract

We present an experimental investigation of the stability limits specific to optical frequency standards using a fiber-optic architecture and semiconductor lasers. A compact setup composed of a semiconductor laser frequency-locked onto an acetylene transition detected in saturated absorption has been implemented using only fiber-optic components. Fiber optic technology allows compact and reliable solutions for various applications. However, for high sensitivity and stability applications such as metrology, residual reflections induced by optical index inhomogeneities in connectors and fiber-coupled components leading to spurious interference significantly limit performance. We have examined the origin of the interference fringes superimposed on the detected signal and the limitations they cause to the frequency stability of the reference. The effects of temperature and beam power fluctuations are also examined. Our results show that the frequency stability is limited in the 10-13 range by the effect of interference fringes due to use of fiber components.