System and method for measuring perturbations utilizing an optical filter and a narrowband optical source

A method of detecting perturbations, the method comprising:

• generating light from a narrowband optical source;
• transmitting a transmitted portion of the light through an optical filter, the optical filter having a power transmission spectrum as a function of wavelength and a group delay spectrum as a function of wavelength, the power transmission spectrum comprising a plurality of peaks each comprising a local maximum and two non-zero-slope regions with the local maximum therebetween, the optical filter having a wavelength-dependent figure of merit proportional to a product of the power transmission spectrum and the group delay spectrum;
• and
• detecting an optical power of:
• the transmitted portion of the light, the reflected portion of the light, or both the transmitted portion of the light and the reflected portion of the light, wherein the light has a wavelength at a non-zero-slope region of a peak of the plurality of peaks, the figure of merit evaluated at the local maximum of the peak greater than the figures of merit evaluated at the local maxima of the other peaks of the plurality of peaks.

A method of detecting perturbations, the method comprising:

• generating light from a narrowband optical source;
• reflecting a reflected portion of the light from an optical filter, the optical filter having a power reflection spectrum as a function of wavelength and a group delay spectrum as a function of wavelength, the power reflection spectrum comprising a plurality of valleys each comprising a local minimum and two non-zero-slope regions with the local minimum therebetween, the optical filter having a wavelength-dependent figure of merit proportional to a product of the group delay spectrum and one minus the power reflection spectrum;
• and
• detecting an optical power of:
• the reflected portion of the light, a transmitted portion of the light transmitted through the optical filter, or both the reflected portion of the light and the transmitted portion of the light, the light having a wavelength at a non-zero-slope region of a valley of the plurality of valleys, the figure of merit evaluated at the local minimum of the valley greater than the figures of merit evaluated at the local minima of the other valleys of the plurality of valleys.