A polarization-separated, phase-shifted interferometer can generate interferograms without moving parts. It uses a phase shifter, such as an electro-optic phase modulator, to modulate the relative phase between sample and reference beams. These beams are transformed into orthogonal polarization states (e.g., horizontally and vertically polarized states) and coupled via a common path (e.g., polarization-maintaining fiber) to a polarizing beam splitter (PBS), which sends them into separate sample and reference arms. Quarter-wave plates in the sample and reference arms rotate the polarization states of the sample and reference beams so they are coupled out of the PBS to a detector via a 45° linear polarizer. The polarizer projects the aligned polarization components of the sample and reference beams onto the detector, where they interfere with known relative phase to produce an output that can be used to map surface topography of the test object.

A system and method are provided for optical homodyne detection in an optical fiber interferometer. A detection signal is obtained by interfering an optical data signal with a phase-modulated optical reference signal. The modulator for the optical reference signal is phase-locked to an oscillatory modulation waveform. In embodiments, the modulator includes a piezoelectric element. In more specific embodiments, the modulator is a piezoelectric optical fiber-stretcher.

A probe for an optical measurement system includes a probe body arranged to be adjustably mounted in a measuring machine for optically measuring a test object. A single mode fiber optically coupled within the probe body transmits a source beam having an instantaneous or sequentially established bandwidth spanning a range of wavelengths to the probe body and also transmits a measurement beam from the probe body toward a detector. An adjustable beam manipulator within the probe body spatially excludes portions of the reference beam over a progression of different size portions from being focused within the acceptance cone of the single mode fiber to more closely balance the intensities of the reflected object beam and the reflected reference beam within the measurement beam.

The present invention discloses a processing method for laser heterodyne interferometric signal based on locking edge with high frequency digital signal. A reference signal and a measurement signal of heterodyne interferometer, after being processed by photodetector, signal amplifier, filtering circuit, voltage comparator and high frequency digital edge locking module, are transferred to pulse counting synchronized latching processing module, to obtain entire cycle interference fringe numbers and filling pulse numbers in one interference fringe cycle, of the reference signal and the measurement signal; the numbers are transferred to a computer to obtain displacement and speed of a measured object; usage of a high frequency digital pulse signal to lock the rising edge of laser heterodyne interferometric signal can improve the gradient of the rising edge of interference signal and eliminate wrong pulse caused by noises, and improve the accuracy and stability of the processing for the following signals.

An optical coherence analysis system uses a laser swept source that is constrained to operate in a stable mode locked condition by modulating a drive current to the semiconductor optical amplifier as function of wavelength or synchronously with the drive voltage of the laser's tunable element based on stability map for the laser.

Our high phase sensitivity wide-field phase cancellation interferometry system allows single-shot, label-free optical sensing of neural action potentials via imaging of optical path length changes. Single-shot sensing and monitoring of single neurons within a neural network should lead to a more comprehensive understanding neural network processing, which is beneficial for the advancement in the field of neuroscience as well as its biomedical applications and impact. Our system cancels the phase profile of the resting neuron from the phase profile of the spiking neuron, improving the sensitivity by two orders of magnitude. Using a detector with an extremely large well depth and an appropriately biased interferometer increases the sensitivity by another order of magnitude, yielding a measurement that is three orders of magnitude more sensitive than those possible with other microscopes.

An optical coherence tomographic device may include a light source, a measurement light generator, a reference light generator, an interference light generator, an interference light detector, and a processor. The interference light detector may include a first and second detector that convert interference light to interference signals, a first signal processing unit that samples the interference signal from the first detector, and a second signal processing unit that samples the interference signal from the second detector. Each of the first and second signal processing units may sample the interference signal at a timing from outside. Light generated by the measurement light generator may at least include first and second correction light. The processor may correct a time lag between sampling timings of the first and second signal processing units by using a first and second correction signal converted from the first and second correction light.

A digitizer and processor device for a swept-source optical coherence tomography (SS-OCT) imaging system, comprising: an input configured to receive an OCT signal; a control input configured to receive a k-clock signal; a combiner unit (130) receiving the OCT signal and the k-clock signal configured to output a composite signal; a digitizing unit (60) arranged to convert the composite signal into a digital composite signal (69); a data processing unit (70) arranged to determine a profile of optical density in a sample that generated the OCT signal based on the digital composite signal (69).

OCT measuring device in the present exemplary embodiment includes: wavelength sweep light source that emits light of which a wavelength is swept; optical interferometer that divides the light into measurement light and reference light, emits measurement light toward measurement surface of measuring target object, and generates an optical interference intensity signal indicating an intensity of interference between measurement light reflected from measurement surface and reference light; electro-optic element which is a phase modulator arranged in a light path of optical interferometer; measurement processor which is a signal generator that derives a position of measurement surface and generates a phase amount indicator signal that indicates a phase amount of phase modulator based on the optical interference intensity signal; and electro-optic element controller which is a phase amount controller that controls the phase amount given to the light that is transmitted through phase modulator.

Disclosed is a stitching-measurement device adapted for performing stitching-measurement on a surface of a concave spherical lens, including: an interferometer, a reference lens, a first plane mirror, a second plane mirror, a first adjustment mechanism, a second adjustment mechanism, a concave spherical object to be measured, a motion table and a control mechanism, the first plane mirror being mounted on the first adjustment mechanism configured to change a position of the first plane mirror; the second plane mirror being mounted on the second adjustment mechanism configured to change a position of the second plane mirror; the concave spherical object to be measured being placed on the motion table configured to change a position of the concave spherical object to be measured; the control mechanism communicating with the interferometer, the first adjustment mechanism, the second adjustment mechanism, and the motion table for issuing control signals, wherein by the first adjustment mechanism and the second adjustment mechanism, an included angle between the first plane mirror and the second plane mirror is adjusted in such a way that light beam incident on the concave spherical object to be measured is inclined by a first angle relative to light beam emitted from the reference lens, thereby avoiding an operation of inclining the concave spherical object to be measured during the stitching-measurement.