Systems and methods for fiber optic fourier spectrometry measurement

A Fourier spectrometer, comprising:

• an interferometer, including:
• a first optical path structure that provides a first optical path, and
• a second optical path structure that provides a second optical path, wherein:
• the first optical path extends from a first path start to a first reflector,
• the first optical path has a first optical path length,
• the second optical path extends from a second path start to a second reflector,
• the second optical path has a second optical path length,
• at least a segment of the second optical path comprises a tunable optical propagation medium and a tuning effectuator, which is configured to receive an optical path difference command and, in response, to effectuate a change in the tunable optical propagation medium that correspondingly changes the optical path difference, which is a difference between the first optical path length and the second optical path length;
• a scan controller, configured to perform a scanning process, comprising generating the optical path difference command;
• an interferometer coupler, configured to receive a subject light, and couple the subject light to the interferometer in a configuration that instantiates:
• a propagation of a first portion of the subject light over the first optical path from the first path start to the first reflector,
• a propagation from the first reflector, over the first optical path from the first reflector to the first path start, of a first reflector reflection of the first portion of the subject light,
• a propagation of a second portion of the subject light along the second optical path from the second path start to the second reflector,
• a propagation from the second reflector, over the second optical path from the second reflector to the second path start, of a second reflector reflection of the second portion of the subject light;
• and
• a spectrometry logic, coupled to the interferometer in a configuration for receiving and combining the first reflector reflection of the first portion of the subject light and the second reflector reflection of the second portion of the subject light, and generating a spectrometry data for the subject light, based at least in part on a Fourier transform of a result of the combining.

A system for measuring at least pressure, acceleration, strain, or temperature, comprising:

• a sensor cavity body, configured to receive an injection light and to provide an injection light optical path for the injected light that includes a hollow cavity first facing surface and a hollow cavity second facing surface, and configured such that changes in the force change a hollow cavity optical path difference between the hollow cavity first facing surface and the hollow cavity second facing surface;
• a splitter-router, configured to:
• receive a sourced light from a light source,
• route the sourced light as the injected light, over an optical fiber to the sensor cavity body,
• receive from the sensor cavity body sensor reflection optical signals, which are responsive to the injected light and comprise hollow cavity first reflection signals from the hollow cavity first facing surface and hollow cavity second reflection signals from the hollow cavity second facing surface, and
• route at least a portion of the cavity body sensor reflection signals, as routed cavity body reflection signals;
• an interferometer, configured to:
• receive the routed cavity body reflection signals,
• propagate the routed cavity body reflection signals such that a first portion of the routed cavity body reflection signals arrives, via a first optical path, at a first reflector and a second portion of the routed cavity body reflection signals arrives, via a second optical path, at a second reflector,
• reflect from the first reflector a portion of the routed sensor reflection signals, as interferometer first reflector signals, and reflect from the second reflector of another portion of the routed sensor reflection signals, as interferometer second reflector signals;
• a phase shifting splitter, configured to:
• receive and combine, into interferometer reflector signals, the interferometer first reflector signals and the interferometer second reflector,
• separate the interferometer reflector signals into separate channel signals, comprising first channel signals, second channel signals, and third channel signals, mutually spaced from one another with respect to phase;
• and
• a computer implemented dynamic measuring logic, comprising a processor coupled to a data memory and an instruction memory, the instruction memory storing processor executable instructions that cause the processor perform the logic to detect changes in the hollow cavity optical path difference, based on the first channel signals, second channel signals, and third channel signals.

A method for measuring quantity, the quantity being force, or temperature, or both, comprising:

• injecting a source light into a sensor body, the sensor body configured to provide an injection light optical path that includes a sensor body first reflective surface and a sensor body second reflective surface, and configured such that changes in the quantity change a sensor body optical path difference, which is between the sensor body first reflective surface and the sensor body first reflective surface;
• receiving, from the sensor cavity body, sensor reflection optical signals comprising sensor body first reflection signals from the sensor body first reflective surface and sensor body second reflection signals from the sensor body second reflective surface;
• routing at least a portion of the sensor reflection signals, as routed sensor reflection signals, to a slab interferometer that includes a slab and a photodetector array;
• and
• computerized dynamic measuring of the quantity, including:
• receiving, into a computer data memory, photodetector sensor signals from the photodetector array, and
• computerized determining of a measurement of the quantity, based at least in part on an optical path difference of the slab, and determining peak positions on the photodetector array of interference fringes.