Rayleigh longitudinal profiling of optical resonances within waveguide grating structures using sidescattered light.

Area of Science:

• Optics and Photonics
• Fiber Optic Sensors
• Materials Science

Background:

• Bragg gratings in fibers are crucial optical components.
• Standard characterization relies on transmission and reflection spectra.
• These methods offer limited information on internal grating properties.

Purpose of the Study:

• To characterize the resonant properties of fiber Bragg gratings (FBGs).
• To explore an alternative method for analyzing the standing-wave intensity profile within FBGs.
• To compare the information obtained from Rayleigh scattering with traditional spectral analysis.

Main Methods:

• Measurement of wavelength-dependent Rayleigh scattering.
• Light propagation along the grating length within the fiber core.
• Analysis of scattering patterns to infer grating characteristics.

Main Results:

• Rayleigh scattering measurements provide detailed information on FBG resonant characteristics.
• The technique successfully maps the standing-wave intensity profile within the grating.
• This profile information is not accessible through conventional transmission or reflection spectra.

Conclusions:

• Rayleigh scattering is a valuable technique for characterizing FBGs.
• It offers unique insights into the internal standing-wave intensity distribution.
• This method complements and extends traditional spectral analysis techniques for FBGs.