US 6,587,188 B2 · Method and sensor arrangement for measuring temperature and strain using an optical fiber embedded in a cover layer on a substrate

Abstract

In a sensor arrangement for sensing temperature and strain, an optical fiber with a Bragg grating therein is arranged on a substrate and embedded in a cover layer. The fiber is initially adhered onto an adhesive carrier, which then positions and applies the fiber onto the substrate. The fiber is point-wise fixed onto the substrate by a binder applied through holes in the adhesive carrier. Next, the carrier is stripped off to leave the fiber on the substrate. A cover layer is applied over the fiber and the substrate. Temperature and strain variations are transmitted from the cover layer into the fiber as non-circularly-symmetrical strains. The strain and temperature can be independently determined using this single sensor, by feeding quasi-depolarized light into the fiber and measuring the overlapping birefringent reflections from the Bragg grating. The full width at half maximum value indicates the temperature, while the Bragg wavelengths indicate the strain and the temperature.

Claims38

Dependent claims

A sensor arrangement for determining a temperature and a strain, comprising:

a substrate having a substrate surface;
an optical sensor arranged directly or indirectly on said substrate surface, wherein said optical sensor comprises at least one optical fiber including a fiber core and a fiber cladding, and a Bragg grating formed in a sensor section of said optical fiber;
and
a cover layer applied onto said substrate and said optical fiber such that said optical fiber is embedded in and at least partially surrounded by said cover layer and secured thereby onto said substrate, and such that a force-transmitting connection is established between said substrate, said cover layer and said optical fiber;
and
wherein said optical sensor is birefringent due to a non-circularly-symmetrical thermomechanical strain that has been transmitted and induced from said cover layer into said optical fiber.

3 more elements

A method of fabricating a sensor arrangement for determining a temperature and a strain, said sensor arrangement including:

a substrate having a substrate surface;
an optical sensor arranged directly or indirectly on said substrate surface, wherein said optical sensor comprises at least one optical fiber including a fiber core and a fiber cladding, and a Bragg grating formed in a sensor section of said optical fiber;
and
a cover layer applied onto said substrate and said optical fiber such that said optical fiber is embedded in and at least partially surrounded by said cover layer and secured thereby onto said substrate, and such that a force-transmitting connection is established between said substrate, said cover layer and said optical fiber;
and
wherein said optical sensor is birefringent due to a non-circularly-symmetrical thermomechanical strain that has been transmitted and induced from said cover layer into said optical fiber;
said method comprising the following steps:
a) providing an adhesive carrier that has an adhesive on one surface thereof and that has a plurality of holes therein arranged along at least one straight or curved row of said holes;
b) positioning and adhering said optical fiber onto said adhesive to extend along said row of holes;
c) positioning said adhesive carrier with said optical fiber adhered thereon relative to said substrate so that said optical fiber is positioned on said substrate surface;
d) applying a binder substance through said holes in said adhesive carrier, onto said optical fiber and said substrate surface, and then curing said binder substance so as to at least spot-wise secure said optical fiber to said substrate surface by said binder substance;
e) after completion of said step d), peeling said adhesive carrier of f of said optical fiber and said substrate while leaving said optical fiber secured onto said substrate surface;
and
f) after said step e), applying at least one layer of a coating material onto said optical fiber and onto said substrate surface, and then curing said coating material to form thereof said cover layer in which said optical fiber is embedded and by which said optical fiber is fixed onto said substrate surface.

11 more elements

Dependencies are inferred from the claim text.

Method and sensor arrangement for measuring temperature and strain using an optical fiber embedded in a cover layer on a substrate

Life of this patent

Method and sensor arrangement for measuring temperature and strain using an optical fiber embedded in a cover layer on a substrate

Life of this patent

Abstract

Claims38