Temperature measurements of photonic circuit components may be performed optically, exploiting a temperature-dependent spectral property of the photonic device to be monitored itself, or of a separate optical temperature sensor placed in its vicinity. By facilitating measurements of the temperature of the individual photonic devices rather than merely the photonic circuit at large, such optical temperature measurements can provide more accurate temperature information and help improve thermal design.

Disclosed are a system and a method for measuring a magnetorefractive effect of an optical fiber. The system comprises a laser, a coupler A, a sensing optical fiber, a reference optical fiber, a carrier generator, a coupler B, a photoelectric detector and a data acquisition and processing module. The coupler A, the sensing optical fiber, the reference optical fiber and the coupler B form a Mach-Zehnder optical fiber interferometer. An external magnetic field influences the refractive index of the sensing optical fiber, so that the optical path difference between two paths of optical signals in the sensing optical fiber and the reference optical fiber is changed, the intensity of an interference optical signal output by the coupler B is changed, and the refractive index change of the sensing optical fiber under the action of the magnetic field is measured by detecting and processing the interference optical intensity.

An interferometric demodulation system for a large capacity fiber grating sensing network is provided by the present disclosure, comprising: a continuous light output end of the nanoscale wide-spectrum light source is connected to an input end of the pulse optical modulator, an output end of the reference grating is connected to an input end of the grating array sensing network, and a third communication end of the optical circulator is connected to an input end of the optical amplifier, an output end of the optical amplifier is connected to an input end of the Mach-Zehnder interferometer, three-channel signal output ends of the Mach-Zehnder interferometer are respectively connected to signal input ends corresponding to the embedded signal processor through the photoelectric converter, and the embedded signal processor controls the heating device to control a temperature of an any one of interference arms of the Mach-Zehnder interferometer.

A method and a system for arbitrary optical waveform generation from an optical input, the system comprising an optical shaper comprising unbalanced interferometers with at least one delay, the delay being selected of at least 0.1 ps, an optical sampling readout selected for measuring optical waveforms of at least 0.1 ps; and an electronic processing unit; wherein the optical input is a picosecond pulse; with a minimal pulse duration before the optical shaper equal to a minimal delay of the optical shaper; the optical shaper splitting and interfering optical pulses; the optical sampling readout collecting data at an output of the optical shaper; and the electronic processing unit comparing the collected data with a preset target and updating the optical shaper from results of the comparison until a maximal match between the output of the optical shaper and the preset target output, wherein the maximal match is determined iteratively using one of: machine-learning, optimization algorithms and iterative search algorithms.

An optical interrogation system, e.g., an OFDR-based system, measures local changes, of index of refraction of a sensing light guide subjected to a time-varying disturbance. Interferometric measurement signals detected for a length of the sensing light guide are transformed into the spectral domain. A time varying signal is determined from the transformed interferometric measurement data set. A compensating signal is determined from the time varying signal which is used to compensate the interferometric measurement data set for the time-varying disturbance. Further robustness is achieved using averaging and strain compensation. The compensation technique may be applied along the length of the light guide.

Local strain and optionally other properties of an optical sensing fiber are detected as a function of position along the optical sensing fiber. A light pulse with a plurality of simultaneous laser modes at mutually different wavelengths is transmitted into the optical sensing fiber. Light produced by backscattering of the light pulse in the optical fiber is fed to a multi-way coupler, via a first and second optical path with different optical path lengths. Intensities of different phase combinations of light from the paths are detected by detectors at the outputs of the multiway coupler. A data processing system computes relative phase values of light from the first and second paths for a series to time points with time delays corresponding to scattering at different positions along the fiber. In an embodiment, inelastically scattered light such as due to Brillouin scattering and/or Raman scattered light is selective passed to the detectors and detected.

A method and system described for sensing a displacement by receiving and propagating a laser light signal with an etched waveguide that is configured to enable an evanescent optical field above the waveguide surface. A movable perturber can be positioned so the perturber interacts with the evanescent optical field above the waveguide surface. An optical phase shift can be induced in the waveguide when the movable perturber is displaced in the evanescent optical field, and the optical phase shift can be measured with an optical readout circuit.

Interferometric measurement signals are detected by a single optical interferometric interrogator for a length of a sensing light guide and an interferometric measurement data set corresponding to the interferometric measurement signals is generated. The interferometric measurement data set is transformed into a spectral domain to produce a transformed interferometric measurement data set. The transformed interferometric measurement data set is compared to a baseline interferometric data set to identify a time-varying signal corresponding to a time-varying disturbance. The baseline interferometric data set is representative of the sensing light guide not being subjected to the time-varying disturbance. A compensating signal is determined from the time-varying signal and used to compensate at least a portion of the interferometric measurement data set for the time-varying disturbance as part of producing a measurement of the parameter.

A waveguide for guiding an electro-magnetic wave comprises: a first waveguide part; and a second waveguide part; wherein the first waveguide part has a first width in a first direction (Y) perpendicular to the direction of propagation of the electro-magnetic wave and the second waveguide part has a second width in the first direction (Y), wherein the second width is larger than the first width; and wherein the first and the second waveguide parts are spaced apart by a gap in a second direction (Z) perpendicular to the first and second planes in which the waveguide parts are formed, wherein the gap has a size which is sufficiently small such that the first and second waveguide parts unitely form a single waveguide for guiding the electro-magnetic wave. The waveguide may be used in numerous applications, such as in a photonic integrated circuit, in a sensor or in an actuator.

A method for distributed acoustic sensing includes sending a first optical pulse down an optical fiber, wherein light from the first optical pulse is backscattered from positions along a length of the optical fiber according to coherent Rayleigh scattering; splitting backscattered light from the first optical pulse into a first portion for a first interferometer and a second portion for a second interferometer, the first interferometer having a first gauge length and the second interferometer having a second gauge length, wherein the first gauge length is different from the second gauge length; detecting a first interferometric signal from the first interferometer responsive to the first portion of backscattered light; detecting a second interferometric signal from the first interferometer responsive to the second portion of backscattered light; and processing the first and second interferometric signals for two different sensing applications adapted for the first and second gauge lengths, respectively.