KR101271571B1 - Ship monitoring system using fiber bragg grating sensor - Google Patents

Abstract

The present invention relates to a ship monitoring system using an optical fiber Bragg grating sensor, and more particularly to a broadband wavelength source for generating an optical wavelength; An optical fiber Bragg grating sensor that reflects only wavelengths satisfying Bragg conditions in an optical wavelength incident from a broadband wavelength source and transmits other wavelengths as they are; A divider configured to receive and distribute a synthesized wavelength obtained by combining the wavelength received from the Bragg grating sensor and the wavelength of the broadband wavelength source; A first photodetector for obtaining a reference wavelength by filtering only wavelengths received from the Bragg grating sensor at the synthesized wavelength received from the splitter, and a second obtaining only a shift wavelength received from the Bragg grating sensor at the synthesized wavelength received from the splitter A photodetector comprising a photodetector; And a unit conversion unit for comparing the wavelengths of the first photodetector with the second photodetector and converting a shift degree of the wavelength into a temperature or a pressure unit. The optical fiber Bragg grating sensor includes a temperature or A ship monitoring system using an optical fiber Bragg grating sensor, which detects a change in pressure, shifts a wavelength by a change in temperature or pressure, and monitors a temperature changed in a unit conversion unit by filtering a shift wavelength and a reference wavelength in a photodetector. It is about.

Description

Ship monitoring system using fiber Bragg grating sensor {SHIP MONITORING SYSTEM USING FIBER BRAGG GRATING SENSOR}

The present invention relates to a ship monitoring system using an optical fiber Bragg grating sensor, and more particularly, to a ship monitoring system using an optical fiber Bragg grating sensor that detects a change in temperature or pressure generated in a ship and monitors it. .

Fiber Bragg Grating is used to engrave several optical fiber Bragg gratings on one strand of fiber according to the length, and then change the refractive index and the wavelength of light reflected from each grating according to ambient temperature or tensile strength. Depending on the characteristics of selectively reflecting or removing light of a specific wavelength. The Fiber Bragg Grating Sensor using this characteristic reflects only wavelengths satisfying Bragg conditions and transmits other wavelengths as it is, thus measuring the wavelength of light reflected from the fiber Bragg grating, thereby measuring temperature, tension, or Pressure, bending, etc. can be detected.

An optical fiber Bragg grating array sensor uses multiple gratings for one strand of optical fiber. In this case, by varying the reflection wavelength of each grating, it is easy to distinguish the physical quantity experienced by a particular grating from the reflected light spectrum.

In the conventional vessel temperature and pressure monitoring system, a temperature or pressure change is sensed using an electrical sensor. However, when the electrical sensor is used to detect a change in the temperature or the pressure of the vessel as described above, there is a disadvantage in that there is noise against electromagnetic interference.

In addition, the use of the electrical sensor has a lot of disadvantages, such as electrical grounding, electrical leakage, etc. in addition to the above disadvantages, a lot of light loss, array sensor is impossible, there are many environmental variables that the sensor can not operate.

An object of the present invention is to provide a ship monitoring system using an optical fiber Bragg grating sensor that can detect the temperature or pressure change of the ship in order to compensate for the above-mentioned disadvantages.

The ship monitoring system using the optical fiber Bragg grating sensor of the present invention for solving the above problems and to achieve the above object,

A broadband wavelength source for generating an optical wavelength; An optical fiber Bragg grating sensor that reflects only wavelengths satisfying Bragg conditions in an optical wavelength incident from a broadband wavelength source and transmits other wavelengths as they are; A divider configured to receive and distribute a synthesized wavelength obtained by combining the wavelength received from the Bragg grating sensor and the wavelength of the broadband wavelength source; A first photodetector for obtaining a reference wavelength by filtering only wavelengths received from the Bragg grating sensor at the synthesized wavelength received from the splitter, and a second obtaining only a shift wavelength received from the Bragg grating sensor at the synthesized wavelength received from the splitter A photodetector comprising a photodetector; And a unit conversion unit for comparing the wavelengths of the first photodetector with the second photodetector and converting a shift degree of the wavelength into a temperature or a pressure unit. The optical fiber Bragg grating sensor includes a temperature or Sensing a change in pressure to shift the wavelength by a change in temperature or pressure, and by filtering the shift wavelength and the reference wavelength in the photodetector is characterized in that it is possible to monitor the changed temperature in the unit conversion unit.

Here, the broadband wavelength source may be either an Er-doped fiber amplifier (EDFA) or a super-luminescent light emitting diode (SLED), and is characterized by generating an optical wavelength of 1270 nm to 1600 nm.

The apparatus may further include a filter in front of the second photodetector of the photodetector, wherein the filter filters the synthesized wavelength received from the splitter according to a straight line of the first function of the wavelength intensity over the wavelength range, and the splitter has three ports. Or circulator 50-50% coupler.

According to the characteristics of the present invention, the ship monitoring system using the optical fiber Bragg grating sensor of the present invention, compared to the existing system by using the optical fiber Bragg grating sensor instead of the electrical sensor, there is no noise for electromagnetic interference, electrical grounding, short circuit There is no effect such as worry.

In addition, it is easy to install because of its small size and light weight, and can be used for measuring almost all kinds of physical quantities.

In addition, the light loss is low, the array sensor can be applied, there is an effect that can be used in an environment where the operation of the sensor is impossible.

1 is a view showing the configuration of a ship monitoring system using an optical fiber Bragg grating sensor according to the present invention,
2 is a view showing the operation characteristics of the light detector of the configuration of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing the configuration of a ship monitoring system using an optical fiber Bragg grating sensor according to the present invention. As shown in Figure 1, the vessel monitoring system using the optical fiber Bragg grating sensor of the present invention is a broadband wavelength source 100, optical fiber Bragg grating sensor 200, distributor 300, light detector 400 and unit conversion unit And 500.

First, the broadband wavelength source 100 is a wavelength source for generating an optical wavelength, and generates an optical wavelength of 1270 nm to 1600 nm, and may be any one of an ED- doped fiber amplifier (EDFA) or a super-luminescent light emitting diode (SLED). This is not limitative.

The optical fiber Bragg grating sensor 200 reflects only wavelengths satisfying the Bragg conditions in the light wavelength incident from the broadband wavelength source 100 and transmits other wavelengths as they are. At this time, the optical fiber Bragg grating sensor 200 detects a change in temperature or pressure in the vessel and shifts the wavelength by a change in temperature or pressure. The change in temperature can be measured in units of 10 pm/° C. and the pressure change is 0.25% FS. Can be measured in units. The optical fiber Bragg grating sensor 200 may detect any one or more of gas, temperature, shape deformation, or vibration in a marine tank, an inboard gas transport pipe, and a marine engine.

The distributor 300 receives a synthesized wavelength obtained by combining the wavelength received from the Bragg grating sensor 200 and the wavelength of the broadband wavelength source 100, and distributes the synthesized wavelength. The distributor 300 may be a three port circulator or 50-50% coupler.

The photodetector 400 includes a first photodetector 410 and a second photodetector 420. The first photodetector 400 filters only the wavelength received from the Bragg grating sensor 200 in the synthesized wavelength received from the distributor 300 to obtain a reference wavelength. The second photodetector 420 filters the shift wavelength received from the Bragg grating sensor 200 in the synthesized wavelength received from the distributor 300 to obtain the shift wavelength. At this time, the filter 450 is further included in front of the second photodetector 420, which filters the synthesized wavelength received from the divider 300 according to a straight line of the linear function of the wavelength intensity over the wavelength range. To filter. The filter 450 may be formed of a thin film of SiO 2 or TiO 2. Hereinafter, an operation characteristic of the light detector 400 will be described in detail with reference to FIG. 2.

2 is a view showing the operating characteristics of the light detector 400 of the configuration of the present invention. As shown in FIG. 2, the photodetector 400 includes a first photodetector 410, a second photodetector 420, and a filter 450. As described above, the first photodetector 410 filters only the reference wavelength from the optical fiber Bragg grating sensor 200 at the synthesized wavelength received from the distributor 300, and the second photodetector 420 receives from the distributor 300. Only the shift wavelength is filtered from the optical fiber Bragg grating sensor 200 in the composite wavelength. Here, the shift wavelength refers to a wavelength of which the wavelength is shifted when there is a temperature or pressure change in the object detected by the optical fiber Bragg grating sensor 200. In addition, the filter 450 located in front of the second photodetector 420 filters the synthesized wavelength received from the distributor 300 by a straight line of the linear function of the wavelength intensity over the wavelength range. For example, when a temperature or pressure change occurs to receive the shift wavelength in the second photodetector 420, the peak value of the wavelength is reduced by the linear function linear. At this time, as shown in A of the graph, the difference in wavelength intensity finally appears in the filtered wavelength of the reference wavelength and the filtered wavelength of the shift wavelength. This A is a measure of how much temperature change has occurred, and is transmitted to the unit conversion unit 500.

The unit conversion unit 500 compares the wavelengths of the first photodetector 410 and the second photodetector 420 of the photodetector 400 to convert the degree of shift of the wavelength into temperature or pressure units. The converted value may be output through a network unit (not shown) and a display unit (not shown).

The display unit receives the temperature or pressure change measurement value converted from the unit conversion unit 500 and displays it, and the network unit is connected between the unit conversion unit 500 and the display unit through an RS-232 or RS-485 serial communication port. Send and receive signals.

While the present invention has been particularly shown and described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of course, this is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the equivalents as well as the claims that follow.

100: broadband wavelength source 200: optical fiber Bragg grating sensor
300: divider 400: photodetector
410: first photodetector 420: second photodetector
450: filter 500: unit conversion unit

Claims (3)

A broadband wavelength source for generating an optical wavelength;
An optical fiber Bragg grating sensor that reflects only wavelengths satisfying Bragg conditions in an optical wavelength incident from a broadband wavelength source and transmits other wavelengths as they are;
A divider configured to receive and distribute a synthesized wavelength obtained by combining the wavelength received from the Bragg grating sensor and the wavelength of the broadband wavelength source;
A first photodetector for obtaining a reference wavelength by filtering only wavelengths received from the Bragg grating sensor at the synthesized wavelength received from the splitter, and a second obtaining only a shift wavelength received from the Bragg grating sensor at the synthesized wavelength received from the splitter A photodetector comprising a photodetector; And
And a unit conversion unit for converting a wavelength shift amount into a temperature or pressure unit by comparing wavelengths of the first photodetector and the second photodetector.
The optical fiber Bragg grating sensor detects a change in temperature or pressure in the vessel, shifts the wavelength by the change in temperature or pressure, and monitors the changed temperature in the unit conversion unit by filtering the shift wavelength and the reference wavelength in the photodetector. Ship monitoring system using optical fiber Bragg grating sensor. The method of claim 1,
The broadband wavelength source may be any one of an ED-doped fiber amplifier (EDFA) or a super-luminescent light emitting diode (SLED),
Ship monitoring system using an optical fiber Bragg grating sensor, characterized in that to generate an optical wavelength of 1270nm to 1600nm. The method of claim 1,
And further comprising a filter in front of the second photodetector of the photodetector,
The filter filters the synthesized wavelength received from the splitter according to the straight line of the linear function of the wavelength intensity over the wavelength range,
The distributor may be a three-port circulator or 50-50% coupler, characterized in that the vessel monitoring system using a fiber Bragg grating sensor.

Images