Disclosed are a device and a method for measuring laser displacement. The device comprises an interferometric measurement module, a laser light source module, a signal modulation module, a control processing module and an optical vernier demodulation module. The control processing module controls the signal modulation module to apply a light source modulation signal to the laser light source module, so that the laser light source module provides two laser beams with fixed frequency difference to the interferometric measurement module. The control processing module controls the interferometric measurement module to perform interferometric measurement. During measurement, lasers respectively interfere in two Fabry-Perot cavities in the interferometric measurement module, and are detected by two photodetectors to form main and secondary measurement interference signals. The optical vernier demodulation module demodulates the main and secondary measurement interference signals obtained by the interferometric measurement module.

A first light source outputs measurement light having a wavelength in infrared range. A second light source outputs guide light having a wavelength in visible range. A fiber coupler includes a first port into which the measurement light is input, a second port into which the guide light is input, and a third port outputting combined light formed by combining the measurement light and the guide light with each other. A measurement unit emits the combined light to a measurement object and receives return light reflected therefrom. A processing unit obtains information relating to a distance, a speed, or an oscillation of the measurement object, based on an interference signal of the return light and the reference light. The fiber coupler is formed by a single mode fiber that has a cutoff wavelength that is shorter than that of the measurement light and longer than that of the guide light.

A system for precision displacement measurement based on a self-traceable grating interference includes a coherent light source, a photoelectric detection module, a self-traceable grating and a signal processing module. The self-traceable grating is arranged on a to-be-measured displacement motion platform. The coherent light source, the photoelectric detection module and the signal processing module are sequentially connected. Laser generated by the coherent light source propagates through the photoelectric detection module and is incident on the self-traceable grating, diffracts with the self-traceable grating, returns to the photoelectric detection module to continue propagating and enters the signal processing module. The signal processing module collects an interference signal to obtain a motion displacement and a motion direction.

The present invention relates to accurately determining a contour of a depolarizing region.

An image processing apparatus extracts a depolarizing region in a polarization-sensitive tomographic image of a subject's eye, and detects, in a tomographic intensity image of the subject's eye, a region corresponding to the extracted depolarizing region. The tomographic intensity image corresponds to the polarization-sensitive tomographic image,

A truncated non-linear interferometer-based sensor system includes an input that receives an optical beam and a non-linear amplifier that generates a probe beam and a conjugate beam from the optical beam. The system's local oscillators are related to the probe beam and the conjugate beam. The system includes a sensor that transduces an input with the probe beam and the conjugate beam. The transduction detects changes in the phase of each of the probe beam and the conjugate beam. The system's phase sensitive detectors detect phase modulations between the respective local oscillators, the probe beam, and the conjugate beam and outputs phase signals based on detected phase modulations. The system measures phase signals indicative of the sensor's input resulting from a sum or difference of the phase signals. The measurement exhibits a quantum noise reduction in an intensity difference, a phase sum, or an amplitude difference quadrature.

A digital measuring device implemented on a photonic integrated circuit, the digital measuring device including a laser source configured to provide light, a first ring resonator configured to produce a first frequency comb of light from the laser source, wherein at least a portion of the first frequency comb of light is directed at a moving object, a local oscillator configured to provide a reference beam, at least one waveguide structure configured to combine the reference beam with light reflected from the moving object to produce a measurement beam, a first multiplexer configured to split the measurement beam into a plurality of channels spaced in frequency, and a plurality of detectors configured to detect an intensity value of each channel of the plurality of channels to measure a distance between the digital measuring device and the moving object.

Methods and systems of eliminating corrupting influences caused by the propagation medium and the data capture devices themselves from useful image features or characteristics such as the degree of symmetry are disclosed. The method includes the steps of obtaining image-plane data using a plurality of data capture devices, wherein the image-plane data is a combined visibility from each of the data capture devices, measuring the closure phase geometrically in the image-plane directly from the image-plane, removing the corruptions from the image features based on the measured closure phase to remove the non-ideal nature of the measurement process, and outputting the uncorrupted morphological features of the target object in the image. The method relies on the Shape-Orientation-Size conservation principle for images produced from three visibilities made from a closed triad of data capture devices. The method includes the idea that true image of the object can be reconstructed from the three interferometer elements, independent of element-based calibration.

A laser device includes a laser configured to generate laser light and a laser control module configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module includes a tunable frequency discriminating element which is preferably continuously frequency tunable, and where the laser control module is placed outside the laser cavity.

A laser device includes a laser configured to generate laser light and a laser control module configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module includes a tunable frequency discriminating element which is preferably continuously frequency tunable, and where the laser control module is placed outside the laser cavity.

An interferometry apparatus comprising: a laser source operable to emit a first light beam; a beam splitter arranged to split the first light beam into an object beam and a reference beam, the object beam passing along an object beam arm and the reference beam passing along a reference beam arm; an adaptive delay line located a distance along the reference beam arm, the adaptive delay line being configured to provide, in use, one or more length-adjusted reference beams; a beam splitter arranged to recombine the object beam from the object beam arm and the length-adjusted reference beam(s) from the reference beam arm; and a photodetector operable to detect interference between the object beam and the length-adjusted reference beam(s).