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公开(公告)号：US20210349068A1
公开(公告)日：2021-11-11
申请号：US17274270
申请日：2019-09-03
申请人： Cranfield University
摘要： An interferometric fluid sensing system is provided. The system comprises: a laser; a plurality of first fibre portions arranged to receive laser light from the laser, wherein each of the first fibre portions comprises a void and an opening to allow fluid from the environment around the corresponding first fibre portion to enter the void, wherein the first fibre portions are configured such that the laser light received by each first fibre portion passes through the corresponding void; a second fibre portion configured to provide a reference arm for the interferometric fluid sensing system; and a detector arranged to receive light from the first and second fibre portions, wherein the system is configured such that the laser light that passes through the void of each first fibre portion is caused to interfere with the light passing through the second fibre portion at or before reaching the detector, wherein each of the first fibre portions is arranged such that that light passing through the void of each first fibre portion travels from the laser to the detector over a different path length from the light passing through the voids of the other first fibre portions, wherein the system is configured such that the wavelength of light provided by the laser varies with time according to a modulated function, the modulated function comprising a first function, which varies through a range of wavelengths, modulated by a second, cyclical carrier function. An interferometric fluid detection method is also provided.
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公开(公告)号：US20180156715A1
公开(公告)日：2018-06-07
申请号：US15572765
申请日：2016-03-22
申请人： Cranfield University
CPC分类号： G01N21/0303 , G01N21/05 , G01N21/31 , G01N21/85 , G01N2021/8578 , G01N2201/08
摘要： This disclosure relates to hollow fibre waveguide spectroscopic gas cells built using connectors and the method for making them. The connectors are used to construct gas cell end pieces which allow gas and light to enter the hollow fibre waveguide simultaneously thus creating a gas cell. The connectors comprise a window which intersects or is in close proximity to a junction of bores within the connector, the bores transmitting gas through the connector to or from the hollow fibre waveguide. Connectors may also be used to connect two sections of fibre together in order to produce longer gas cells which enhance the signal-to-noise ratio of spectroscopic measurements. The window, which is at least partially transparent at the wavelength of the light used for spectroscopic purposes, is affixed so as to maintain a gas tight seal for the gas cell. These gas cells provide a combination of long path length and low volume and are well suited to mid-infrared spectroscopic applications which require a fast response time or low flow rate.
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公开(公告)号：US20170047709A1
公开(公告)日：2017-02-16
申请号：US15304153
申请日：2015-04-09
申请人： Cranfield University
CPC分类号： H01S5/06808 , G01N21/27 , G01N21/39 , G01N33/0047 , G01N2021/399 , G01N2201/062 , H01S5/02415 , H01S5/06804
摘要： This invention generally relates to a method of controlling emission wavelength of a light emitting device, and a system for wavelength control of a light emitting device, for example for wavelength stabilisation of a laser diode. One method of controlling emission wavelength of a light emitting device comprises: determining an indication of series resistance of the device, the series resistance comprising ohmic resistance of the device; providing a current through the device to maintain light emission of the device; measuring a forward voltage of the device during said light emission, the forward voltage being across an impedance comprising impedance of an active region of the device and the series resistance; determining an indicator of active region voltage on the basis of the measured forward voltage and the determined indicator of series resistance; and controlling a temperature of the device on the basis of the determined indicator of active region voltage.
摘要翻译： 本发明一般涉及一种控制发光器件的发射波长的方法，以及用于发光器件的波长控制的系统，例如用于激光二极管的波长稳定。 控制发光器件的发射波长的一种方法包括：确定器件串联电阻的指示，串联电阻包括器件的欧姆电阻; 提供通过该装置的电流以维持装置的发光; 在所述发光期间测量所述器件的正向电压，所述正向电压跨过包括所述器件的有源区域的阻抗和所述串联电阻的阻抗; 基于所测量的正向电压和确定的串联电阻指示器确定有源区电压的指示; 以及基于所确定的有源区电压的指示器来控制所述装置的温度。
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