OPTICAL SENSOR AND METHOD FOR MEASURING THE PRESSURE OF A FLUID

摘要

Optical sensor (1) for measuring the pressure of a fluid comprises a transducer (3) with a deformable membrane to which membrane two fibre Bragg gratings (FBG) are attached, one at each side of the membrane. The sensor further comprises a tuneable small band light source (2) for providing light with a small band wavelength varying in time to the fibre Bragg gratings, a photodetector (5) for detecting light diffracted from the fibre Bragg gratings, and a timer (7) for determining at which points in time the diffracted light is detected. This optical sensor does not require a reference light source and neither a temperature sensor. The sensor can be used to measure the level of a liquid. Method for measuring the pressure of a fluid, comprises the step of providing light with a small band wavelength varying in time to two fibre Bragg gratings attached to the opposite sides of a membrane. The method further comprises the step of detecting the light diffracted by the fibre Bragg gratings and the step of determining at which points in time the diffracted light is detected. The method can be used to measure the level of a liquid.

主权项

1. An optical sensor for measuring a pressure of a fluid comprising:
a transducer comprising
a membrane that is deformable as a result of a difference in pressure at a first side of the membrane and a second, opposite side of the membrane,a first fibre Bragg grating (33) situated at the first side of the membrane in such a way that a deformation of the membrane results in a deformation of this first fibre Bragg grating, anda second fibre Bragg grating situated at the second side of the membrane in such a way that a deformation of the membrane results in a deformation of this second fibre Bragg grating;the optical sensor further comprising:
a light source for providing light to the first and the second fibre Bragg grating, a photodetector for detecting light coming from the first and the second fibre Bragg grating, wherein the light source is a tuneable light source for providing light at a wavelength that is swept in time, and wherein the optical sensor comprises a timer for determining a time interval that lapses between the points in time at which the photodetector detects the light coming from the first and the second fibre Bragg grating.