A method for high-accuracy wavefront measurement based on grating shearing interferometry, which adopts a grating shearing interferometer system comprising an illuminating system, an optical imaging system under test, an object plane diffraction grating plate, an image plane diffraction grating plate, a two-dimensional photoelectric sensor, and a calculation processing unit. The object plane diffraction grating plate and the image plane diffraction grating plate are respectively arranged on the object plane and the image plane of the optical imaging system under test. The shearing phase of 1.sup.st-order diffracted beam and −1.sup.st-order diffracted beam is exactly extracted through phase shifting method, and the original wavefront is obtained by carrying out reconstruction algorithm according to a shear ratio of 2s, such that the accuracy of wavefront measurement of the optical imaging system under test is improved, wherein s is the shear ratio of the grating shearing interferometer.

Apparatus and associated methods relate to determining the wavelength of a narrow-band light beam. The narrow-band light beam is passed through an optical filter. The optical filter has complementary and monotonically-varying transmission and reflection coefficients within a predetermined band of wavelengths. The predetermined band of wavelengths includes the wavelength of the narrow-band light beam. A first photodetector detects amplitude of a first portion of the narrow-band light beam transmitted by the optical filter. A second photodetector detects amplitude of a second portion of the narrow-band light beam reflected by the optical filter. The wavelength of the narrow-band light beam is determined, based on a ratio of the determined amplitudes of the first and second portions of the narrow-band light beam transmitted and reflected, respectively.

An interferometer system comprises a sample interferometer arm for guiding a first wave to a sample, and receiving a reflected wave from the sample and a phase amplifier for amplifying a phase shift of the reflected wave, to provide phase-shift-amplified intermediate wave. The interferometer system can also comprise an additional interferometer arm for guiding an additional wave to combine with the intermediate wave, to provide an output wave, and a detector for detecting the output wave.

A laser system comprising two phase-locked solid-state laser sources is described. The laser system can be phase-locked at a predetermined offset between the operating frequencies of the lasers. This is achieved with high precision while exhibiting both low noise and high agility around the predetermined offset frequency. A pulse generator can be employed to generate a series of optical pulses from the laser system, the number, duration and shape of which can all be selected by a user. A phase-lock feedback loop provides a means for predetermined frequency chirps and phase shifts to be introduced throughout a sequence of generated pulses. The laser system can be made highly automated. The above features render the laser system ideally suited for use within coherent control two-state quantum systems, for example atomic interferometry, gyroscopes, precision gravimeters gravity gradiometers and quantum information processing and in particular the generation and control of quantum bits.

An interferometer system including: an optical system arranged to split a radiation beam from a laser source into a first beam along a first optical path and a second beam along a second optical path, and recombine the first beam and the second beam to a recombined beam, a detector to receive the recombined beam and to provide a detector signal based on the received recombined beam, and a processing unit, wherein a first optical path length of the first optical path and a second optical path length of the second optical path have an optical path length difference, and wherein the processing unit is arranged to determine a mode hop of the laser source on the basis of a phase shift in the detector signal.

An interferometer system including: an optical system arranged to split a radiation beam from a laser source into a first beam along a first optical path and a second beam along a second optical path, and recombine the first beam and the second beam to a recombined beam, a detector to receive the recombined beam and to provide a detector signal based on the received recombined beam, and a processing unit, wherein a first optical path length of the first optical path and a second optical path length of the second optical path have an optical path length difference, and wherein the processing unit is arranged to determine a mode hop of the laser source on the basis of a phase shift in the detector signal.

A system for stabilizing a scale factor associated with an optic rotation sensor comprises an optic rotation sensor that generates an optic signal in response to a rotation of the optic rotation sensor. A sensor detection system produces a rotation signal as a function of the optic signal and rotation of the optic rotation sensor. A first waveguide guides a portion of the optic signal for an interaction length, and produces a first processed optic signal. A second waveguide receives a portion of the optic signal from first waveguide through evanescent coupling, and produces a second processed optic signal. A wavemeter detector receives the optic signals and measures the effective interferometric wavelength (EIW) of the light based on the optic signals. A scale factor correction system receives the rotation signal and the EIW, and measures the correct rotation signal by processing the rotation signal and the EIW.

Various implementations of the invention compensate for “phase wandering” in tunable laser sources. Phase wandering may negatively impact a performance of a lidar system that employ such laser sources, typically by reducing a coherence length/range of the lidar system, an effective bandwidth of the lidar system, a sensitivity of the lidar system, etc. Some implementations of the invention compensate for phase wandering near the laser source and before the output of the laser is directed toward a target. Some implementations of the invention compensate for phase wandering in the target signal (i.e., the output of the laser that is incident on and reflected back from the target). Some implementations of the invention compensate for phase wandering at the laser source and in the target signal.

Various implementations of the invention compensate for “phase wandering” in tunable laser sources. Phase wandering may negatively impact a performance of a lidar system that employ such laser sources, typically by reducing a coherence length/range of the lidar system, an effective bandwidth of the lidar system, a sensitivity of the lidar system, etc. Some implementations of the invention compensate for phase wandering near the laser source and before the output of the laser is directed toward a target. Some implementations of the invention compensate for phase wandering in the target signal (i.e., the output of the laser that is incident on and reflected back from the target). Some implementations of the invention compensate for phase wandering at the laser source and in the target signal.

Provided are various embodiments related to an electronic device. According to an embodiment, an electronic device may comprise: an IR (infrared light) transmission unit for outputting IR light; an IR reception unit for receiving IR light; and processor. The processor is configured to: identify a first IR transmission signal to be transmitted to an external device; identify a first time interval and a second time interval, which correspond to the first IR transmission signal; output first IR light corresponding to at least a part of the first IR transmission signal through the IR transmission unit in the first time interval; identify whether second IR light having the intensity larger than or equal to a threshold is received by the IR reception unit in the second time interval; and when the second IR light having the intensity larger than or equal to the threshold is received by the IR reception unit in the second time interval, interrupt transmission of the IR transmission signal. In addition, other embodiments may be possible.