A high-performance single-chip, integrated-optics-based OCT system is disclosed, where the length of the reference arm is digitally variable. The reference arm includes a plurality of switch stages comprising a 22 tunable wavelength-independent waveguide switch that can direct an input light signal onto either of two different-length output waveguides. In some embodiments, the directional couplers are thermo-optic based. Some embodiments include a solid-state scanning system for scanning a sample signal along a line of object points on the sample under test.

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 Time Domain Optical Coherence Tomography system using a modulation scheme multiplexes the scanning range of the delay line into different spectral bands. Such a modulation scheme may allow for power consumption reduction compared with a single delay line element since the same modulation pattern is being used for several channels. In an example, the optical coherence tomography system may include a plurality of stages, each stage having a group delay element. The distinct group delays may be introduced to scan a sample with distinct electrical frequency bands at distinct axial scanning depth ranges.

Aspects of the present disclosure involve a system and method for performing radio frequency interferometry using optical fiber sensing. Optical fiber sensing is performed as a reference signal is defined and compared, in the optical domain, to incoming signals to obtain interference fringe patterns that can be used to decode phase shift offsets with respect to the designated reference signal. The phase shift offsets can be determined by first optically modulating the reference and incoming signals using a laser source as the carrier. In the optical domain, the reference and incoming signals are combined using an optical coupler and then converted back to the electrical domain for processing.

The present invention relates to an arrangement for the generation of images of optical sections of a three-dimensional (3D) volume in space such as an object, scene, or target, comprising: an illumination unit, an optical arrangement for the imaging of the object onto at least one spatially resolving detector, a scanning mechanism for scanning the entire object and a signal processing unit for the implementation of a method for digital reconstruction of a three-dimensional representation of the object from images of said object as obtained by said detector (which may be in a form of a hologram), wherein the optical arrangement includes a diffractive optical element (herein a phase pinhole), realized using a Spatial Light Modulator (SLM) configured to mimic an actual physical pinhole, while allowing the formation of a three-dimensional representation for a specific point of interest in said object, such that for each scanning position a single hologram or an image is recorded.

Aspects of the present disclosure involve a system and method for performing radio frequency interferometry using optical fiber sensing. Optical fiber sensing is performed as a reference signal is defined and compared, in the optical domain, to incoming signals to obtain interference fringe patterns that can be used to decode phase shift offsets with respect to the designated reference signal. The phase shift offsets can be determined by first optically modulating the reference and incoming signals using a laser source as the carrier. In the optical domain, the reference and incoming signals are combined using an optical coupler and then converted back to the electrical domain for processing.

A method and system for instantaneous time domain optical coherence tomography (iTD-OCT) provides instantaneous optical depth profiles in an axial direction to a sample having scattering properties or that is at least partially reflective. An iTD-OCT instrument includes a spectroscopic detector having an internal optical axis and an array of detector pixels. A reference beam having a fixed optical path length is superpositioned along the optical axis with a measurement beam that includes back-scattered photons from the sample. The detector pixels capture a time domain interference pattern arising within the spectroscopic detector due to optical path length differences between photons from the reference beam and photons from the measurement beam. The iTD-OCT instrument may be implemented as a robust solid-state device with no moving parts.

A Time Domain Optical Coherence Tomography system using a modulation scheme multiplexes the scanning range of the delay line into different spectral bands. Such a modulation scheme may allow for power consumption reduction compared with a single delay line element since the same modulation pattern is being used for several channels. In an example, the optical coherence tomography system may include a plurality of stages, each stage having a group delay element. The distinct group delays may be introduced to scan a sample with distinct electrical frequency bands at distinct axial scanning depth ranges.

An optical coherence tomography apparatus includes a light source, a light coupling module, and an optical path difference generating module. The light source emits a coherent light. The light coupling module divides the coherent light into a first incident light and a second incident light. The first incident light is emitted to an item to be inspected and a first reflected light is generated. The second incident light is emitted to the optical path difference generating module, a second reflected light is generated according to the second incident light by the optical path difference generating module through changing the transparent/reflection properties of at least one optical devices of the optical path difference generating module, so that there is a optical path difference between the first reflected light and the second reflected light.

An OCT instrument operable to acquire a B-scan representing a section of a sample, the sample being inclined relative to a plane normal to an axial direction along which depth information of the B-scan is acquired, the OCT instrument being configured to: split light from a swept light source into signal light and reference light; receive signal light reflected from scan locations on the sample; generate sideband light by adjusting an optical frequency of the reference light; sample, for each scan location, a respective time-varying interference signal resulting from interference between the sideband light and the received signal light; generate the B-scan from the sampled signals; and control the optical frequency during the scan such that an image of the sample in the B-scan is less inclined to a lateral direction in the B-scan than in a B-scan of the section acquired by the OCT instrument without the control.