Disclosed herein are optical integration technologies, designs, systems and methods directed toward Optical Coherence Tomography (OCT) and other interferometric optical sensor, ranging, and imaging systems wherein such systems, methods and structures employ tunable optical sources, coherent detection and other structures on a single or multichip monolithic integration. In contrast to contemporary, prior-art OCT systems and structures that employ simple, miniature optical bench technology using small optical components positioned on a substrate, systems and methods according to the present disclosure employ one or more photonic integrated circuits (PICs), use swept-source techniques, and employ a widely tunable optical source(s).

An optical coherence analysis system comprising: a first swept source that generates a first optical signal that is tuned over a first spectral scan band, a second swept source that generates a second optical signal that is tuned over a second spectral scan band, a combiner for combining the first optical signal and the second optical signal to form a combined optical signal, an interferometer for dividing the combined optical signal between a reference arm leading to a reference reflector and a sample arm leading to a sample, and a detector system for detecting an interference signal generated from the combined optical signal from the reference arm and from the sample arm.

A polarization sensitive spectral interferometer apparatus and method for analyzing a sample by optical energy reflected from the sample. The polarization sensitive spectral interferometer apparatus and method determines polarization properties of the sample by optical energy reflected from the sample.

An optical coherence tomography device comprises a light generator, a dispersive medium, an optical coupler and a detector. The light generator is adapted to generate a series of input pulses of coherent light, each input pulse having an input pulse width. The dispersive medium has an input that is optically coupled to the light generator and an output for output pulses. The dispersive medium is adapted to stretch the input pulse width to an output pulse width of each of the output pulses by chromatic dispersion. The optical coupler is adapted to couple the output pulses into a reference arm and a sample arm. The optical coupler is further adapted to superimpose light returning from the reference arm and the sample arm. The detector is adapted to detect an intensity of interference of the superimposed light with a temporal resolution of a fraction of the output pulse width.

An OCT apparatus includes a wavelength selector provided on an optical path between a light source unit and a pair of optical detection units, and having a wavelength selectivity with equal wavenumber intervals. A differential detection unit detects a differential between two interference lights detected by the two optical detection units, and an information acquisition unit obtains peak values in the temporal waveform of the intensity of the interference lights and acquires information about an object on the basis of the obtained peak values.

Methods for synchronizing an Optical Coherence Tomography (OCT) system including detection when a plurality of A-line scans obtained from reflected light of a cantilever scanning fiber within a probe oscillating along a scanning path that increases in amplitude over time are no longer being obtained at a point along the oscillating scanning path when the scanning fiber reaches a minimum speed, determining a value by which a phase angle of the oscillating scanning path is out of synchronization with the plurality of A-line scans, and adjusting a trigger clock for the obtaining the plurality of A-line scans based on the value.

In a measurement target model representing a measurement target, this measurement sensitivity calculation device uses, as measurement sensitivity, an optical path length difference between a first optical path length indicating the length of an optical path through which light emitted from a light emitter to the measurement target travels before being received by a first light receiver spaced apart by a first distance from the light emitter and a second optical path length indicating the length of an optical path through which light emitted from the light emitter travels before being received by a second light receiver spaced apart by a second distance from the light emitter, calculates the measurement sensitivity for each depth of the measurement target, and outputs the measurement sensitivity calculated for each depth of the measurement target.

A swept-source OCT imaging system for imaging a region of an object, comprising: a swept light source which generates a beam of varying wavelength; a scanning element which scans the beam across the object; an interferometer which generates interference light by combining light scattered by the object (owing to the scan) with reference light; a photodetector which generates an electrical signal (S) having frequency components spanning a frequency band and caused by interference of the scattered light with the reference light; a band-pass filter module which band-pass filters the electrical signal; and a sample acquisition module which samples the filtered electrical signal. The band-pass filter module extracts at least some of the frequency components spanning the frequency band from the electrical signal. The sample acquisition module band-pass samples the filtered electrical signal.

A measurement apparatus for measuring a thickness of a semiconductor wafer includes: an optical system configured to perpendicularly irradiate a sample wafer and a reference wafer with light, and receive interference signals of the light reflected on front and back surfaces of the respective wafers; a signal processor configured to perform frequency analysis of the interference signals received by the optical system to obtain peak positions of a point spread function of the respective wafers; and a calculator configured to calculate a thickness tsample of the sample wafer based on the peak position x of the sample wafer and the peak position y of the reference wafer obtained by the signal processor, and a thickness treference of the reference wafer.