A head-mounted display system includes a wearable frame assembly and a display assembly mounted to the wearable frame assembly and configured to provide display light for viewing by a user eye. A camera mounted to the wearable frame assembly is configured to image a surrounding real-world environment. One or more strain gauges each have one or more variable strain parameters based at least in part on an amount of strain applied to the head-mounted display system. A logic machine is configured to assess an alignment of one or both of the display assembly and the camera based at least in part on the one or more strain parameters for each strain gauge of the one or more strain gauges.

A line monitoring system may include a laser source to launch a probe signal over a first bandwidth, a polarization maintaining tap to receive and split the probe signal, into a first portion and a second portion, a polarization rotator to receive the first portion and send the first portion to a transmission system, a return tap to receive the second portion and to receive a return signal from the transmission system, wherein the return signal being derived from the first portion, a photodetector coupled to receive an interference signal from the return tap, wherein the interference signal is generated by a mixing the return signal and the second portion, where the photodetector is arranged to output a power signal based upon the interference signal, and a power measurement system to measure the power signal at a given measurement frequency over a second bandwidth, comparable to the first bandwidth.

The method and system utilized the measurement of the “absolute” velocities or equivalent parameters of the electromagnetic devices and objects, which are defined as the velocities relative to the real origin of the electromagnetic wave, to accurately picture their impacts on the propagation and measurement of the electromagnetic wave and compensate for these impacts correspondingly. The comprehensive information of the “absolute” velocities, including both the measured values and the calculated right timings, is utilized to calibrate and control the electromagnetic device and calculate the results to improve performance and accuracy. The method and system include the absolute velocity measurement, the calibration and control of the device, and the computation of the right timings and results.

A method for measuring optical characteristics of a Mach-Zehnder type optical modulation device having an incident part, a waveguide for propagating light incident from the incident part, and a plurality of emitting parts each for emitting light. The method includes inputting light from a light source to the incident part of the optical modulation device through a first optical fiber, receiving emitted lights emitted from the plurality of emitting parts of the optical modulation device by a plurality of light receivers, obtaining a total value of currents by converting electric signals into currents and summing the currents, the electric signals being outputted by the plurality of light receivers receiving the emitted lights, and aligning the incident part of the optical modulation device and the first optical fiber based on the total value of currents.

A method for measuring optical characteristics of a Mach-Zehnder type optical modulation device having an incident part, a waveguide for propagating a light incident from the incident part, and a plurality of emitting parts each for emitting the light. The method includes inputting a light from a light source to the incident part of the optical modulation device through a first optical fiber, receiving emitted lights emitted from the plurality of emitting parts of the optical modulation device by a plurality of light receiving parts, obtaining a total value of currents by converting electric signals into the currents and summing the currents, the electric signals being outputted by the plurality of light receivers in receiving the emitted lights, and aligning the incident part of the optical modulation device and the first optical fiber based on the total value.

A method of characterizing a multimode optical fiber results in a measure of estimated modal bandwidth (EMB) that is independent of the bandwidth of the light used in the characterization. The method includes propagating pulses of light along the multimode optical fiber at prescribed radial positions relative to an optical axis of the multimode optical fiber and detecting output pulses from the multimode optical fiber corresponding to the pulses of light propagated along the multimode optical fiber at the prescribed radial positions relative to the optical axis of the multimode optical fiber. An estimated modal bandwidth of the multimode optical fiber is calculated in a manner that accounts for chromatic dispersion of the multimode optical fiber.

A method of testing a photonic device includes providing a plurality of optical test signals at respective inputs of a first plurality of inputs of an optical input circuit located on a substrate, combining the plurality of optical test signals into a combined optical test signal at an output of the optical input circuit, transmitting the combined optical test signal through the output to an input waveguide of an optical device under test, the optical device under test being located on the substrate, and measuring a response of the optical device under test to the combined optical test signal. Each of the plurality of optical test signals comprises a respective dominant wavelength of a plurality of dominant wavelengths.

A non-contact system for measuring an insertion loss of a cable assembly with cable fibers includes a light source system that emits light and a launch connector supporting launch fibers. A detector system includes receive fibers supported by a receive connector. The detector system has detectors optically coupled to the receive fibers, with one detector directly optically coupled to the light source system for calibration. A first movable stage supports the launch connector and a second movable stage supports the receive connector. A launch optical system images output end faces of the launch fibers onto input end faces of the cable fibers of the cable assembly. A receive optical system images output end faces of the cable fibers onto input end faces of the receive fibers. The light exiting the receive fibers is detected and processed to determine the insertion loss of the cable assembly.

A photonic testing device includes a substrate, an optical device under test (DUT) disposed over the substrate, and an optical input circuit disposed over the substrate. The optical input circuit includes a first plurality of inputs each configured to transmit a respective optical test signal of a plurality of optical test signals. Each of the plurality of optical test signals includes a respective dominant wavelength of a plurality of dominant wavelengths. The optical input circuit further includes an output coupled to an input waveguide of the optical DUT. The output is configured to transmit a combined optical test signal comprising the plurality of optical test signals.

The invention concerns an optoelectronic chip including a pair of optical inputs having a same bandwidth, and each being adapted to a different polarization, at least one photonic circuit to be tested, and an optical coupling device configured to couple the two inputs to the circuit to be tested.