A novel wavemeter with 64 attometer spectral resolution based on Rayleigh speckle obtained from single-mode fiber

In this article, a novel method of wavelength measurement with a spectral resolution of 64 attometers (am) based on Rayleigh speckle obtained from a single-mode fiber (SMF) is proposed. A commercial standard SMF is used to provide Rayleigh backscattering signals and measured by an optical frequency-domain reflectometry (OFDR) based system. The Rayleigh backscattering in SMF is a disordered process and provides high-sensitivity wavelength-dependent speckles. In the experiments, by extracting the Rayleigh speckles from a 2-km SMF, we achieve a 64-am spectral resolution (standard deviation) with a measurement refresh rate of 3.3 kHz. Compared with some similar disordered media based wavemeter schemes, the wavelength information can be directly read out from the Rayleigh speckles without using complex algorithms, since the Rayleigh speckle is a 1-D image and shows a linear relationship with the wavelength change, which makes this scheme simple and prospective for high spectral resolution applications.