公开(公告)号：US06208776B1

公开(公告)日：2001-03-27

申请号：US09057067

申请日：1998-04-08

Applicant: John D. Prohaska ,  Lothar U. Kempen ,  Robert A. Lieberman

Inventor： John D. Prohaska ,  Lothar U. Kempen ,  Robert A. Lieberman

IPC: G02B616

CPC classification number: G01L1/246 ,  G01D5/344 ,  G01D5/35383 ,  G01R33/0327 ,  G02B6/021 ,  G02B6/02109 ,  G02B6/02195 ,  G02B6/278 ,  G02B6/29319

Abstract: A sensor system comprises a broadband light source, a birefringent sensor, a detection circuit, and a signal processing unit. The preferred detection circuit further includes a variable frequency oscillator, a modulator, and a photodetector. The modulator modulates the output of the birefringent sensor with a modulation signal from the variable frequency oscillator. The modulation produces an interference signal having a variable interference frequency. By determining the frequency of the modulation signal from the variable frequency oscillator that minimizes the interference frequency, the detection system is able to determine the difference in frequency between first and second spectral components of the output of birefringent sensor. The detector may be constructed using entirely solid state optics/electronics. The preferred fiber grating sensor comprises a birefringent optical fiber having a cladding and a core. The cladding has first and second side holes formed therein that extend substantially parallel to the core, and that are substantially coextensively located with respect to each other along the length of the optical fiber. The first and second side holes are preferable positioned such that, in transverse cross section of the optical fiber, a first radial line that extends from the core to the first side hole is substantially perpendicular to a second radial line that extends from the core to the second side hole.

Abstract translation: 传感器系统包括宽带光源，双折射传感器，检测电路和信号处理单元。 优选的检测电路还包括可变频率振荡器，调制器和光电检测器。 调制器利用来自可变频率振荡器的调制信号来调制双折射传感器的输出。 调制产生具有可变干扰频率的干扰信号。 通过确定使干扰频率最小化的可变频率振荡器的调制信号的频率，检测系统能够确定双折射传感器的输出的第一和第二频谱分量之间的频率差。 检测器可以使用完全固态光学元件/电子元件构造。 优选的光纤光栅传感器包括具有包层和芯的双折射光纤。 包层具有形成在其中的第一和第二侧孔，其基本上平行于芯延伸，并且沿着光纤的长度相对于彼此基本共同设置。 第一和第二侧孔优选地定位成使得在光纤的横截面中，从芯延伸到第一侧孔的第一径向线基本上垂直于从芯延伸到第二侧孔的第二径向线 第二侧孔。

公开(公告)号：US6014215A

公开(公告)日：2000-01-11

申请号：US59872

申请日：1998-04-14

Applicant: Lothar U. Kempen ,  John D. Prohaska ,  Robert A. Lieberman

Inventor： Lothar U. Kempen ,  John D. Prohaska ,  Robert A. Lieberman

IPC: G01D5/26 ,  G01B9/02

CPC classification number: G01D5/266

Abstract: A fiber optic sensor system comprises an optical fiber, a first reflector and a second reflector. The first reflector provides a fixed reference for measuring the optical path length between the second reflector and a reference reflector. The first and second reflectors respectively receive first and second portions of light emitted by the optical fiber and then reflect the light back to the optical fiber. The optical path length between the first and second reflectors varies in accordance with a sensed parameter. In operation, first and second interferograms are acquired that are produced by the interference of light reflected from the first and second reflectors with light reflected from a reference reflector. The first and second interferograms are then used to determine an optical path length between first and second reflectors. Finally, the optical path length between the first and second reflectors is used to determine the value of the sensed parameter.

Abstract translation: 光纤传感器系统包括光纤，第一反射器和第二反射器。 第一反射器提供用于测量第二反射器和参考反射器之间的光程长度的固定参考。 第一和第二反射器分别接收由光纤发射的光的第一和第二部分，然后将光反射回光纤。 第一和第二反射器之间的光程长度根据感测参数而变化。 在操作中，获取由第一和第二反射器反射的光与从参考反射器反射的光的干涉产生的第一和第二干涉图。 然后使用第一和第二干涉图来确定第一和第二反射器之间的光程长度。 最后，使用第一和第二反射器之间的光程长度来确定感测参数的值。