A time-domain or frequency domain system includes, a sample light path between a source interface and a detector interface, a reference light path between the source interface and the detector interface, and a photonic integrated circuit, wherein the reference light path is at least partially separate from the sample light path, wherein the sample light path includes a forward sample light path between the source interface and a sample interface, and a backward sample light path between the sample interface and the detector interface, wherein the forward sample light path and the backward sample light path are at least partially provided by the photonic integrated circuit, and wherein the photonic integrated circuit includes an integrated sample-side polarization beam splitter arranged in the forward sample light path and the backward sample light path.

The invention discloses a four-quadrant interferometry system based on an integrated array wave plate. PBS splits an output laser light into two paths, the reflected light and the transmitted light are respectively transformed into reference light and measuring light, the reference light and the measuring light are converged in PBS, the converging light enters a signal receiving unit and is split into four beams, and the four beams irradiate on a four-quadrant interference signal detector with an integrated array wave plate. The invention solves the problems that the existing signal detection system occupies a large space, is not conducive to array integration, and cannot be used in scenes with high space and size requirements.

A device for measuring a substrate for semiconductor lithography with a reference interferometer for ascertaining the change in the ambient conditions, wherein the reference interferometer comprises a means for changing the optical path length of a measurement section of the reference interferometer, and a method for correcting cyclic error components in the reference interferometer using same.

A device for measuring a substrate for semiconductor lithography with a reference interferometer for ascertaining the change in the ambient conditions, wherein the reference interferometer comprises a means for changing the optical path length of a measurement section of the reference interferometer, and a method for correcting cyclic error components in the reference interferometer using same.

The invention relates to a control system (100) for a fiber optic gryoscope, comprising a phase modulator (110) for modulating a phase of a light signal (115) and a control unit (120) for producing a control signal (125), by the value of which the phase is modulated and which is fed to the phase modulator (110). The control signal changes statistically and does not have an average value.

Apparatus, systems, and methods are used for detecting the alignment of a feature on a substrate using a polarization independent interferometer. The apparatus, system, and methods include optical elements that receive light that has diffracted or scattered from a mark on a substrate. The optical elements may split the diffracted light into multiple subbeams of light which are detected by one or more detectors. The diffracted light may be combined optically or during processing after detection. The system may determine alignment and/or overlay based on the received diffracted light having any polarization angle or state.

One or more devices, systems, methods and storage mediums for performing common path optical coherence tomography (OCT) with a controlled reference signal and efficient geometric coupling are provided. Examples of such applications include imaging, evaluating and diagnosing biological objects, such as, but not limited to, for Gastro-intestinal, cardio and/or ophthalmic applications, and being obtained via one or more optical instruments, such as, but not limited to, optical probes (e.g., common path probes), common path catheters, common path capsules and common path needles (e.g., a biopsy needle). Preferably, the OCT devices, systems methods and storage mediums include or involve a reference reflection or a reference plane that is at least one of: (i) disposed in the collimation field or path; and (ii) is perpendicular (or normal) or substantially perpendicular (or substantially normal) to light propagation. One or more embodiments may include beam shaping optics to properly image luminal or other hollow structures or objects.

A fiber optic transducer is provided. The fiber optic transducer includes a fixed portion configured to be secured to a body of interest, a moveable portion having a range of motion with respect to the fixed portion, a spring positioned between the fixed portion and the moveable portion, and a length of fiber wound between the fixed portion and the moveable portion. The length of fiber spans the spring. The fiber optic transducer also includes a mass engaged with the moveable portion. In one disclosed aspect of the transducer, the mass envelopes the moveable portion.

An interference observation apparatus includes a light source which outputs incoherent light, a beam splitter, a sample holding table, an objective lens, a reference mirror, a lens, an aberration correction plate, a piezo element, a tube lens, a beam splitter, an imaging unit, a photodetector, an image acquisition unit, and a control unit. The control unit obtains an interference intensity of combined light on the basis of a detection signal output from the photodetector, and adjusts an interference optical system to increase the interference intensity.

A displacement measuring device includes an optical module for refracting or reflecting light; a beam splitting module including a polarizing beam splitting layer for allowing light with a first polarization direction to pass through and reflecting light with a second polarization direction; a light source for generating a first light beam with the first polarization direction and a second light beam with the second polarization direction, wherein the first light beam is reflected by a measured object after passing through the optical module and the beam splitting module, and the second light beam is reflected by the polarizing beam splitting layer after passing through the optical module; an image sensor for sensing an interference pattern generated by the reflected first and second light beams; and a processing unit for calculating a displacement value of the measured object according to the interference pattern.