Abstract:
An optical characterisation system is described for characterising optical material. The system typically comprises a diffractive element (104), a detector (106) and an optical element (102). The optical element (102) thereby typically is adapted for receiving an illumination beam, which may be an illumination response of the material. The optical element (102) typically has a refractive surface for refractively collimating the illumination beam on the diffractive element (104) and a reflective surface for reflecting the diffracted illumination beam on the detector (106). The optical element (102) furthermore is adapted for cooperating with the diffractive element (104) and the detector (106) being positioned at a same side of the optical element (102).
Abstract:
An optical demultiplexer comprises an optical fiber, a single collimator lens, a diffraction grating, and a photodetector array including photodetectors, wherein the output light from the optical fiber is demultiplexed through the collimator lens and the diffraction grating and focused on the photodetectors to form a light spot distorted because of the aberration of the optical system of the optical demultiplexer, and the photodetector array receives the substantially whole light spot. The photodetector array can be a linear array where photodetectors are linearly arranged or a matrix array where photodetectors are arranged in a matrix.
Abstract:
A small-sized and low-cost wavelength division multiplexer having little insertion loss, little polarization dependence and a broad wavelength bandwidth, the wavelength division multiplexer adopting a grating configuration in which an incident light is retroreflected, exit lights from respective grooves are enhanced by interference effect in the incident direction of the light, wave surfaces of evanescent waves in the grooves are parallel to the normal direction of the grating and phases of the evanescent waves in the respective grooves agree with each other. The wavelength division multiplexer has high diffraction efficiency in each of TM and TE polarized lights at a several-order diffraction order and accordingly has a broad wavelength bandwidth and remarkably low polarization dependence.
Abstract:
An optical demultiplexer has an optical fiber, a single collimator lens, a diffraction grating, and an array of photodetectors. A light beam emitted from the optical fiber is demultiplexed by the collimator lens and the diffraction grating into light beams, and the light beams are focused by the collimator lens as beam spots deformed due to an aberration of an optical system of the optical demultiplexer onto the photodetectors. The photodetectors are arranged to accommodate and detect all the deformed focused beam spots. The array of photodetectors comprises a linear array of photodetectors or a matrix of photodetectors.
Abstract:
A light beam (6) is applied to a waveguide (3) in order to measure properties of the beam (6), e.g. the wavelength. According to the invention, the waveguide (3) has locally and/or time-varying resonances, e.g. by suitably designed grid couplers (4, 5). A light signal (7) is thus generated in the waveguide (3) as a direct measurement of the property to be measured and can be further processed by suitable means or evaluated. It is thus possible, for example, advantageously to produce a simple and inexpensive spectrometer.
Abstract:
Gase lassen sich wegen ihrer gasspezifischen Absorption im infraroten Spektralbereich mittels eines Spektrometers selektiv nachweisen. Die bekannten Geräte liefern zwar recht genaue Ergebnisse, sie sind jedoch im allgemeinen teuer, von beachtlicher Größe und stellen erhöhte Anforderungen an die Bedienung und Wartung. Für die kontinuierliche Überwachung eines Gasstromes oder eines Gasraumes wird ein spektrometrischer Sensor angegeben, der aus einem als Mikrostrukturkörper hergestellten einstückigen Formteil besteht. Der Raum zwischen Spiegelgitter und Eintritts- bzw. Austrittsspalt für die IR-Strahlung enthält das nachzuweisende Gas. Der Sensor ist kompakt und robust; er ist auch für transportable Geräte geeignet. Er läßt sich in großer Stückzahl kostengünstig herstellen und ist in Metall-Ausführung auch bei erhöhter Temperatur einsetzbar. Mit dem neuen Sensor kann man die Sicherheit von Anlagen, in denen brennbare, giftige oder andere Gase enthalten sind oder auftreten können, auf wirtschaftliche Weise erhöhen.