An optical alignment system includes a LADAR sub-system including: a laser source and a probe configured to deliver probe illumination from the laser source to a first optical surface of the optical system and an additional optical surface of the optical system. The probe is further configured to receive a first measurement signal from the first optical surface and an additional measurement signal from the additional optical surface of the optical system. The system also includes a detector configured to receive a first combined signal and an additional combined signal from an optical coupling assembly. The system further include a controller configured to determine a relative distance between the first optical surface and the additional optical surface based on the first combined signal or the additional combined signal.

According to examples, a fiber-optic testing source for testing a multi-fiber cable may include a laser source communicatively coupled to a plurality of optical fibers connected to a connector. The fiber-optic testing source may include at least one photodiode communicatively coupled to at least one of the plurality of optical fibers by at least one corresponding splitter to implement a communication channel between the fiber-optic testing source and a fiber-optic testing receiver. The communication channel may be operable independently from a polarity associated with the multi-fiber cable. The fiber-optic testing receiver may include a plurality of photodiodes communicatively coupled to a plurality of optical fibers. The fiber-optic testing receiver may include at least one laser source communicatively coupled to at least one of the plurality of optical fibers by at least one corresponding splitter to implement the communication channel between the fiber-optic testing receiver and a fiber-optic testing source.

A low-cost, data-fitting-free robust methodology configured to distinguish the coupling condition of an arbitrary resonance, applicable in one example to a micro-resonator of a multi-micro-resonator optical integrated circuit. The method includes registering the resonator cavity response to a rapid-phase shift of the on-resonance pump field. From the registered feature of the time-dependent transmission characteristic acquired with an optical detector, the sign of a difference between the values of intrinsic loss of the cavity and the coupling rate (?.sub.i??.sub.c) is directly read out, thereby resulting not only in a more accurate estimation of the intrinsic loss as compared with related art, but also in facilitating practically-realizable inspection of massively integrated photonic platforms with micro-resonators.

An electronic wafer inspecting method includes: rotating the wavelength transparent wafer, emitting, from a light source coupled with an interferometric device, two light beams, to form, a measurement volume and having a vaiable inter-fringe distance within the volume, a time signature of a defect intersecting the measurement volume depending on an inter-fringe distance where the defect intersects the volume, the device and the wafer arranged so that the measurement volume extends into a wafer region, collecting the light scattered by the wafer region, emitting a signal representing the variation in the intensity of the collected light per time, detecting in the signal, a frequency of the intensity, the frequency being the time of the passge of a defect through the measurement volume, determining, based on the value of the inter-fringe distance at the location where the defect passes, the position of the defect.

An interferometer apparatus for an optical fiber system and method of use is described. The interferometer comprises an optical coupler and optical fibers which define first and second optical paths. Light propagating in the first and second optical paths is reflected back to the optical coupler to generate an interference signal. First, second and third interference signal components are directed towards respective first, second and third photodetectors. The third photodetector is connected to the coupler via a non-reciprocal optical device and is configured to measure the intensity of the third interference signal component directed back towards the input fiber. Methods of use in applications to monitoring acoustic perturbations and a calibration method are described.

A light intensity distribution pattern measurement device according to the present disclosure includes: a two-dimensional imaging sensor for receiving multiplexed light that is obtained by multiplexing transmitted light obtained by injecting one branched light of first continuous light into an optical fiber under measurement, reference light that is the other branched light of the first continuous light, and local light; and a signal processing unit for performing digital signal processing on a light reception signal I (t) of each pixel obtained by the two-dimensional imaging sensor, in which the signal processing unit measures a light intensity distribution pattern, by calculating a square of an autocorrelation function between the light reception signal I (t) and a light reception signal I (t+) obtained by shifting the light reception signal by time , for each pixel of the two-dimensional imaging sensor.

A device according to the present disclosure: acquires a group delay time difference between eigenmodes, at a specific wavelength, in a coupled two-core fiber; acquires spatial mode dispersion between the eigenmodes, at the specific wavelength, in the coupled two-core fiber; and calculates an average power coupling coefficient between cores, at the specific wavelength, within an entire length of the coupled two-core fiber by using the group delay time difference, the spatial mode dispersion, and a length of the coupled two-core fiber.

The present disclosure includes a light injecting unit that injects a frequency-swept probe light into one end of an optical fiber targeted for measurement, injects a pump light into the other end of the optical fiber targeted for measurement, with respect to the probe light, and thereby amplifies the probe light in the optical fiber targeted for measurement, a light receiving unit that receives a multiplexed light obtained by multiplexing a local light with the probe light, an interference waveform measurement unit that measures an interference waveform between the probe light and the local light, a fundamental mode time waveform analysis unit that acquires a fundamental mode time waveform of the probe light, based on the interference waveform, and a control calculation unit that calculates losses and crosstalk at loss and crosstalk occurrence points of the optical fiber targeted for measurement, based on the fundamental mode time waveform.

Apparatus and methods for fast quantitative measurement of perturbation of optical fields transmitted, reflected and/or scattered along a length of an optical fibre can be used for point sensors as well as distributed sensors or the combination of both. In particular, this technique can be applied to distributed sensors while extending dramatically the speed and sensitivity to allow the detection of acoustic perturbations anywhere along a length of an optical fibre while achieving fine spatial resolution. Advantages of this technique include a broad range of acoustic sensing and imaging applications. Typical uses are for monitoring oil and gas wells such as for distributed flow metering and/or imaging, seismic imaging, monitoring long cables and pipelines, imaging within large vessel as well as for security applications.

An optical line testing device for measuring at least a cutting position of an optical line according to the present invention includes: a first wavelength tunable laser source configured to generate a first optical signal in which a plurality of wavelengths appear alternately and periodically; a second wavelength tunable laser source configured to generate a second optical signal which is identical to the first optical signal but has an adjustable delay time; and an interferometer configured to cause interference between a reflected optical signal, corresponding to the first optical signal, which is returning after having been emitted to the optical line, and the second optical signal to output an interference signal.