A low coherence interferometry imaging system comprising a common-path interferometer that is at least partially integrated as part of a planar lightwave circuit is disclosed. Imaging systems in accordance with the present invention are implemented in integrated optics without the inclusion of highly wavelength-sensitive components. As a result, they exhibit less wavelength dependence than PLC-based interferometers of the prior art. Further, the common-path interferometer arrangement of the present invention avoids polarization and wavelength dispersion effects that plague prior-art PLC-based interferometers. Still further, an integrated common-path interferometer is smaller and less complex than other integrated interferometers, which makes it possible to integrate multiple interferometers on a single chip, thereby enabling multi-signal systems, such as plane-wave parallel OCT systems.

There is described an interferometer for use in an optical locker. The interferometer comprises at least two transparent materials having different thermal path length sensitivities. The interferometer is configured such that an input beam is split by the interferometer into first and second intermediate beams, which recombine to form an output beam, the first and second intermediate beams travelling along respective first and second intermediate beam paths which do not overlap. At least one of the intermediate beam paths passes through at least two of the transparent materials. A length of each intermediate beam path which passes through each transparent material is selected such that an optical path difference between the first and second intermediate beam path is substantially independent of temperature.

An optical interferometer includes a branching-combining unit, a first optical system, a second optical system, and a drive unit. The branching-combining unit includes a branching surface, an incident surface, a first output surface, a combining surface, and a second output surface on an interface of a transparent member, the branching surface partially reflects incident light and outputs as first branched light, and transmits the rest of the incident light into the interior as second branched light, the combining surface partially combines the first branched light and the second branched light to be output to the outside as first combined light, and combines the rest of the first branched light and the second branched light to be propagated into the interior as second combined light, and the second output surface partially outputs the second combined light to the outside.

A displacement detection device is capable of stably and accurately detecting an amount of displacement. A polarization maintaining fiber has a length not to be equal to a length obtained by dividing, a product of an integral multiple of twice a length of a resonator times a refractive index of the resonator and a beat length obtained from a difference between propagation constants of two polarization modes, by a wavelength of the light source, is selected from a range including a length equal to the above length. The polarization maintaining fiber includes multiple polarization maintaining fibers fitted to each other by removable connectors.

There is described an interferometer for use in an optical locker. The interferometer comprises at least two transparent materials having different thermal path length sensitivities. The interferometer is configured such that an input beam is split by the interferometer into first and second intermediate beams, which recombine to form an output beam, the first and second intermediate beams travelling along respective first and second intermediate beam paths which do not overlap. At least one of the intermediate beam paths passes through at least two of the transparent materials. A length of each intermediate beam path which passes through each transparent material is selected such that an optical path difference between the first and second intermediate beam path is substantially independent of temperature.

An optical coherence tomography (OCT) interferometer includes at least a first optical fiber of a first type having a first length, in series with a second optical fiber of a second type which is different than the first type and having a second length, in at least one of the sample path and/or the reference path of the OCT interferometer. The dispersion characteristics of the first optical fiber and the second optical fiber are significantly different than each other. As a result, the total group delay dispersion of a first portion of the laser light passing through the sample path and the total group delay dispersion of the second portion of the laser light passing through the reference path may offset each other at the detector.

This disclosure generally relates to an optical coherence tomography (OCT) system. This disclosure particularly relates to an OCT system with a multi-pass dispersion compensation cell incorporated into its reference arm. This disclosure further relates to a hand-held compact OCT system suitable for inspection of an ear of a mammal.

There is described an interferometer for use in an optical locker. The interferometer comprises at least two transparent materials having different thermal path length sensitivities. The interferometer is configured such that an input beam is split by the interferometer into first and second intermediate beams, which recombine to form an output beam, the first and second intermediate beams travelling along respective first and second intermediate beam paths which do not overlap. At least one of the intermediate beam paths passes through at least two of the transparent materials. A length of each intermediate beam path which passes through each transparent material is selected such that an optical path difference between the first and second intermediate beam path is substantially independent of temperature.

The invention relates to a full-field OCT method for generating an imaging of an ocular fundus (31), in which short-coherent light (22) is emitted and split into an object beam path (25) and a reference beam path (24). The object beam path (25) is directed onto the ocular fundus (33). The reference beam path (24) and a portion of the object beam path (25) reflected by the ocular fundus (31) are directed onto an image sensor (32), such that an interference between the reference beam path (24) and the object beam path (25) occurs on the image sensor (32), wherein the reference beam path (24) impinges on the image sensor (32) at an angle deviating from the object beam path (25). Before impinging on the image sensor (32), the reference beam path (24) impinges on an optical correction element (27) in order to reduce a chromatic aberration within the reference beam path (24). Intensity information and phase information is determined from a capturing of the image sensor. A focus-adjusted image of the ocular fundus is calculated. The invention also relates to a system that is suitable for carrying out said method. Images of the ocular fundus can be captured without the beam path being previously adapted to the refractive power of the eye lens.

A miniature, micrometer-accuracy, three-dimensional (3D) position-to-optical displacement sensor that has at least one extrinsic Fabry-Perot interferometer (EFPI) in Z direction and a series of plasmonic metasurface resonators with distinctive wavelength-selective characteristics in X and Y directions. The interferometer comprises at least one single mode optic fiber for light propagation, and a substrate mirror to create a light interference fringe as a function of distance between the mirror and the distal end of the optic fiber. Each plasmonic resonator is capable of modifying the substrate mirror and comprises an array of multiple unit nanostructure unit cells that are arranged in a two-dimensional (2D) square lattice or array in the X-Y plane. The nanostructure unit cells are preferably inscribed in the top layer of a three-layer thin film via the focused ion beam (FIB).