A spectroscope for measuring a spectrum of input light includes a fringe former that forms first fringes having a first pitch by splitting the input light, a diffraction grating that disperses each of the first fringes, a moire pattern former that forms a moire pattern by overlaying the first fringes that have been dispersed, on second fringes having a second pitch different from the first pitch, and an image pickup device that measures the spectrum of the input light by detecting the moire pattern. At least one of the fringe former and the moire pattern former includes a cylindrical lens array.

An optical system comprising a randomizer that has a plurality of randomly positioned scatterers for scattering and thereby randomizing light to generate a speckle pattern and a detector for detecting the speckle pattern to determine at least one property of the light and/or change in at least one property of the light.

A process for characterizing an optical source including a fixed cavity having a free spectral range, the process including: generating a first radiation; receiving at least a portion of this first radiation by at least one sensor; measuring a signal by each sensor and for each scanned state of the source; on the basis of the signals measured, and for each scanned state of the source, calculating a first data item which represents the wavelength of the first radiation, the calculation including, for each scanned state of the source, a selection of a selected value of the first data item from a plurality of possible values, the selection including the elimination of the values of the first data item which do not correspond to a modulo constant of the free spectral range of the fixed cavity expressed according to the units of the first data item.

A phase modulation structure includes a recording surface including phase angle recording regions in a plurality of calculated element regions corresponding to reconstruction points of an image on a one-to-one basis, each phase angle recording region being formed of a plurality of unit blocks in each of which a phase angle is recorded, the phase angle being calculated based on a phase that is a sum of a plurality of phases of light from the corresponding reconstruction points; and a representative area that is one of divisions of the calculated element region, the representative area being obtained by radially dividing the calculated element region centered on a point on the calculated element region, the point being obtained by extending a normal line from the corresponding reconstruction point to the calculated element region on the recording surface.

According to one embodiment, a quality control method of a position measurement light source includes irradiating light of the position measurement light source on a plurality of marks having different heights and measuring a relationship between the height of the mark and an intensity of light reflected by the mark. The quality control method includes identifying a wavelength of the position measurement light source by comparing measurement data acquired by the measuring to reference data of a relationship between the height of the mark and an intensity of reflected light for each of a plurality of wavelengths.

An interferometer for use in remote sensing systems includes a beam splitter that separates an input wave into a reflected wave, which travels along a first optical path within an upper interferometer arm, and a transmitted wave, which travels along a second optical path within a lower interferometer arm. The reflected and transmitted waves are subsequently recombined by the beam splitter for imaging onto a sensor. A highly dispersive element is incorporated into at least one of the pair of interferometer arms. Due to anomalous dispersion, a frequency shift in a wave transmitted through a dispersive element changes the optical path length within its corresponding arm. As a result, the recombined wave produces an interference pattern with a measurable phase change that can be utilized to calculate the original frequency shift in the input wave with great precision and potential sub-Hertz sensitivity.

Described are various configurations of integrated wavelength lockers including asymmetric Mach-Zehnder interferometers (AMZIs) and associated detectors. Various embodiments provide improved wavelength-locking accuracy by using an active tuning element in the AMZI to achieve an operational position with high locking sensitivity, a coherent receiver to reduce the frequency-dependence of the locking sensitivity, and/or a temperature sensor and/or strain gauge to computationally correct for the effect of temperature or strain changes.

Described are various configurations of integrated wavelength lockers including asymmetric Mach-Zehnder interferometers (AMZIs) and associated detectors. Various embodiments provide improved wavelength-locking accuracy by using an active tuning element in the AMZI to achieve an operational position with high locking sensitivity, a coherent receiver to reduce the frequency-dependence of the locking sensitivity, and/or a temperature sensor and/or strain gauge to computationally correct for the effect of temperature or strain changes.

Conventionally, wavelength locking and monitoring has been achieved used various components, including calibrated etalon filters, gratings, and arrays of color filters, which offer fairly bulky solutions that require complicated controls. An improved on-chip wavelength monitor comprises: a combination comb filter comprising a plurality of comb filters, each for receiving a test beams, and each comb filter including a substantially different FSR, e.g. 10 to 20 the next closest FSR. A controller dithers a phase tuning section of each comb filter to generate a maximum or minimum output in a corresponding photodetector indicative of the wavelength of the test signal.

The invention relates to a three-dimensional interferometer (100) for measuring a light field generated by an object (110), in particular the determination of an electric field (E1.sub.ij, E2.sub.ij), especially of the phase (1.sub.ij, 2.sub.ij) or of the phase (1.sub.ij, 2.sub.ij) and of the intensity or the absolute value of the electric field (E1.sub.ij, E2.sub.ij), having a first interferometer arm (150), which can be so configured or adjusted, especially configured, that a first light beam runs through it, a second interferometer arm (152) so configurable or adjustable, especially configured, that a second light beam runs through it, a beam splitter (101)that is configuredlocated between an object point (112) of the object (110) on the one hand and the first interferometer arm (150) and the second interferometer arm (152) on the other hand, to split a light beam emanating from the object point (112) at the beam splitter (101) into the first light beam and the second light beam, a detection plane (131) or detection surface, which is located after the first interferometer arm (150) and the second interferometer arm (152) and which is configured so that on it the first light beam and the second light beam are brought into inference in an interference area (132), and an overlap device (106) located between the detection plane (131) on the one hand and between the first interferometer arm (150) and the second interferometer arm (152) on the other hand, wherein the beam splitter (101), the first interferometer arm (150), the second interferometer arm (152), the overlap device (106) and the detection plane (131) can be configured or adjusted, especially configured so that there is an object point (112) of the object (110) exactly a central ray (114) emanating from the object point (112) which is split at the beam splitter (101) into a first central ray (120) and a second central ray (121), wherein the central ray (114) is a part of the light beam, the first central ray (120) is part of the first light beam and runs through the first interferometer arm (150) and the second central ray (121) is part of the second beam and runs through the second interferometer arm (152), and wherein the first central ray (120) and the second central ray (121) overlap in a central image point (133) on the detection plane (131) in the interference a