An optical detector system comprises a hermetic optoelectronic package, an optical bench installed within the optoelectronic package, a balanced detector system installed on the optical bench. The balanced detector system includes at least two optical detectors that receive interference signals. An electronic amplifier system installed within the optoelectronic package amplifies an output of at least two optical detectors. Also disclosed is an integrated optical coherence tomography system. Embodiments are provided in which the amplifiers, typically transimpedance amplifiers, are closely integrated with the optical detectors that detect the interference signals from the interferometer. Further embodiments are provided in which the interferometer but also preferably its detectors are integrated together on a common optical bench. Systems that have little or no optical fiber can thus be implemented.

The invention relates to a method for signal processing in optical coherence tomography by means of a tunable light source (swept source), comprising the following steps: tuning the light source and sensing a signal intensity of the light source in linear dependence on the respective wave number (k) of the tunable light source and producing a signal intensity distribution in dependence on k; applying a window function to the sensed signal intensity distribution and producing a weighted signal intensity distribution; and applying a fast Fourier transform (FFT) to the weighted signal intensity distribution; and characterized in that, in the tuning of the light source, the tuned frequency spectrum is limited to a passband of the window function.

An SS-OCT apparatus includes a clock generator configured as an interferometer including an optical path through which part of light emitted from a light source passes, the optical path being split into a first optical path and a second optical path having an optical path length difference relative to the first optical path, to generate a clock used by a converter sampling an analog signal; a tomographic image obtaining unit configured to obtain a tomographic image of a fundus by using a digital signal converted from the analog signal sampled by the converter using the generated clock; and a scan unit configured to scan illumination light across the fundus at a scan angle of 47 degrees or more in air. The tomographic image obtaining unit is configured to obtain a tomographic image of the fundus at a distance of 4.0 mm more within an eyeball in a depth range.

A method for characterising high aspect ratio (HAR) structures etched in a substrate includes, for at least one structure, an interferometric measurement step, carried out with a low-coherence interferometer positioned on a top surface of the substrate, for measuring with a measurement beam, at least one depth data relating to a depth of the HAR structure, and a first adjusting step for adjusting a diameter, at the top surface, of the measurement beam according to at least one top critical dimension (top-CD) data relating to a width of the HAR structure.

A method and system implementing the method for characterising structures etched in a substrate, such as a wafer, includes at least one structure etched in the substrate, an imaging step including the following steps: capturing, with an imaging device positioned on the top surface of the substrate, at least one image of a top surface of the substrate, and measuring a first data relating to the structure from at least one captured image, at least one interferometric measurement step, carried out with a low-coherence interferometer positioned on the top surface, for measuring with a measurement beam positioned on the structure, at least one depth data relating to a depth of the structure; and a first adjusting step for adjusting the measurement beam according to the first data.

Optical coherent receiver arrays are described. The optical coherent receiver arrays include an integrated array of photodetectors separated by integrated mirrors which may cause interference of received free space optical and local oscillator signals. The mirrors may serve as splitters, helping to align the received signal and local oscillator to cause interference. The photodetectors of the optical coherent receiver array may be electrically coupled in various manners to read out the signals. The optical coherent receiver array may be implemented in an optical coherence tomography (OCT) imaging system in some embodiments.

Provided is an optical measurement device configured so that a high-accuracy three-dimensional image can be obtained. An emission angle of a ray of light is changed in such a manner that the rotation frequencies of two motors configured to rotatably drive a first optical path changing unit and a second optical path changing unit is controlled. The ray of light is emitted to a front three-dimensional region, and reflected light is obtained. Then, calculation is made by a computer, and in this manner, three-dimensional data on a measurement target object is obtained. The amount (vibration amount) of axial backlash or play of a rotary mechanism, such as a motor shaft, along which the ray of light is emitted is measured in real time, and such a backlash or play amount is subtracted from a three-dimensional image obtained by the computer. Consequently, a high-accuracy three-dimensional image is obtained.

A photonic integrated circuit wavelength tunable laser device includes a gain element integrated into a photonic integrated circuit. The gain element provides optical gain to an optical signal. A tunable filter is integrated into the photonic integrated circuit. A modulator is integrated into the photonic integrated circuit that modulates the optical signal as a function of time, wherein the gain element, the tunable filter, and the modulator form a wavelength tunable laser device having a wavelength that tunes as a function of time.

An integrated optical system includes a frequency tunable optical source. A reference path is coupled to the frequency tunable source. The integrated optical system also includes a photonic integrated circuit (PIC) comprising a coherent optical receiver that is optically coupled to the reference path. An optical phased array is optically coupled to the frequency tunable source and is positioned to couple light to and from a sample. The integrated optical system is configured such that when the frequency tunable optical source is tuned in optical frequency, the coherent optical receiver produces electrical signals having optical information about the sample.

Real-time swept source OCT data is most often sampled using a specially cut hardware k-clock. The present invention involves mathematically resampling signals within an FPGA-based data acquisition board based on data sampled from a wide free spectral range reference interferometer. The FPGA can then multiply up the reference clock rate to achieve greater imaging depth. The Nyquist fold-over depth can thus be programmed from a standard reference to an arbitrary depth, much as PLL frequency synthesizer can produce many frequencies from a standard stable reference. The system is also capable of real-time performance.