THIS SYSTEM

Technical Field:

The presented invention relates to a low-cost new system design of fiber optic pressure and strain sensors in which ultra-high sensitive fiber loop ringdown spectroscopy technique and its application.

State of the Art:

Pressure and strain sensor studies using fiber optic cables are widely available in the literature. As a system, the light source is formed using fiber and power meters/photodetectors and oscilloscopes. Such systems have disadvantages such as low sensitivity, large margin of error due to the fact that light interacts with the parameter to be measured once. Another system design was created using a light source, a fiber loop, a power meter/photodetector, and an oscilloscope. These systems offer ultra-high accuracy and high accuracy measurement possibilities due to the fact that as a result of traveling the light in the fiber loop, it interacts with the parameter to be measured multiple times. In the literature, fiber loop ringdown spectroscopy (FLRDS) technique, laser/LED light sources with different center wavelength and pressure and voltage sensor studies with different fiber types have been performed. However, the application of a pressure and strain sensor in which the FLRDS technique is used with a 1550 nm LED light source and a single-mode fiber loop is not found in the literature.

The reliability of the results is low due to the high measurement accuracy and the high margin of error in fiber optic sensors that do not use the FLRDS technique. In systems where single-mode fiber is not used, data loss is very large. For this reason, either high- power light sources are used, or short fiber optic sensors are preferred. Li and his team (doi.org/10.1109/JLT.2015.2446652). fiber Bragg Grating for simultaneous measurement of force and temperature that are available in the market (FBG) sensors using Wavelength interrogation technique strength and time have sought to measure the temperature. Because many system components such as working wavelength scanning fiber laser, EDFA fiber amplifier, acusto optical modulator are used, it has a high cost-effective, large volume-occupying, portable, complex and costly system. The technique and sensor used by Li and his team is a design that can be affected by temperature. Therefore, this situation has negative effects on the measurement quality and reliability of the results.

Wang and Scherrer (doi.org/10.1364/OL.29.000352) they performed a pressure sensor study using a 1650 nm center wavelength laser and a single-mode fiber loop. The pressure measurements were carried out by measuring the damping times of the light in the fiber ring. The system design includes a diode laser light source, a single-mode fiber loop formed by 2x1 fiber combiners, a photodetector and an electronic control unit. They determined the sensor performance by studying parameters such as stability, repeatability, dynamic range. Wang and Scherrer's study is a new system design study. They performed a pressure sensor study on a single-mode fiber loop using a 1650 nm center wavelength laser. Although the applied technique has ultra-high accuracy, the laser light source and system equipment used increase the system cost.

Bayuwati and Waluyo (doi.org/10.1063/1.4941617) they conducted a displacement sensor study by examining the relationship between fiber deceleration and optical loss in a standard single-mode fiber with an LED light source with a center wavelength of 1050 nm. Although the displacement sensor is used in the form of a coil or loop in the system in this study, it is a very different design from the FLRDS fiber optic system. One end of the fiber loop was connected to a sliding rod, and the displacement was studied by processing the signals captured by the power meter of the beam coming out of the fiber. The fiber loop created here is very different from the sensor system, where a small part of the beam is employed using the FLRDS technique and couplers. Here the diameter of the ring varies with displacement. In the technique and system used by Bayuwati and Waluyo, both a low- wavelength light source was used and a fiber loop ringdown was not used. The measurement accuracy is very low compared to the accuracy offered by the FHDSS technique.

The document numbered US2005269490A1 describes the ‘Long-term gratings sensor methods and devices’ . The invention relates to optical sensors and systems and methods that use sensors to detect one or more related compounds in a test environment. In one embodiment, an optical sensor comprising a long-period grating and a solid-phase micro extraction (SPME) film is exposed to a test medium such that one or more related compounds are selectively cleaved into the solid-phase micro-extraction film. At least one optical property of the sensor exposed to the test medium is compared with at least one corresponding optical property of the sensor in the absence of a test medium, where a difference in the optical property is indicative of one or more related compounds in the test medium. Methods and systems can use long-term grating sensors with or without SPME film.

In the invention US2005269490A1, the LPG sensor region and the laser light source were also used as the light source. There are many pressure and strain sensor applications in the literature. These applications were carried out using a laser light source and a fiber loop ringdown formed by single-mode fiber. Sensor studies were also carried out using LED light source and single-mode fiber.

Due to the fact that there is no sensor operation in the single-mode fiber loop ringdown using a 1550 nm center wavelength LED beam in the current technique, a new technology is needed.

Description of the Invention:

The difference between fiber loop ringdown spectroscopy (FLRDS) and other studies using a single-mode fiber loop with a 1550 nm center wavelength LED light source and all other applied techniques is that it is quite economical, easy to use, stable, takes up little volume, has a high sensitivity and portable early detection sensor system. The sensor system, which includes a high-precision spectroscopic measurement technique, is widely available due to its low cost. Even if the techniques and sensor systems used in previous studies in the literature have high sensitivity, they have many disadvantages, such as their high cost, cannot be portable, cannot be widely used, and do not have a small volume.

Our system, which is the subject of the invention, will offer the possibility of widespread use, unlike laboratory systems. By etching the sensorhead region, it can also be ensured that the system sensitivity is enhanced. In this way, a sensor system or sensor network that can enable the early detection of many parameters such as erosion, landslides, landslip, floods, cracks, etc. will be designed to minimize serious damage and loss of life.

The simple system design allows easy and quick system setup due to easy assembling of system components. Hence, it is a low cost system due to the short assembly time. In addition, the invention has a solid structure.

Description of the Figures:

The invention will be described with reference to the accompanying figures, so that the features of the invention will be more clearly understood and appreciated, but the purpose of this is not to limit the invention to these certain regulations. On the contrary, it is intended to cover all alternatives, changes and equivalences that can be included in the area of the invention defined by the accompanying claims. The details shown should be understood that they are shown only for the purpose of describing the preferred embodiments of the present invention and are presented in order to provide the most useful and easily understandable description of both the shaping of methods and the rules and conceptual features of the invention. In these drawings;

Figure 1 a schematic representation of the FLRDS sensor system designed in a laboratory environment using a 1550 nm center wavelength LED light source, an optical lens system, a single-mode fiber loop, a power meter, and a computer. Figure 2 a schematic representation of a cost-effective and portable FLRDS fiber optic pressure and strain sensor system using a single-mode fiber loop with a 1550 nm center wavelength LED light source.

Figure 3 a schematic representation of the system that shows the method of operation.

The figures to help understand the present invention are numbered as indicated in the attached image and are given below along with their names.

Description of References:

1. LED light source

2. Optical lens assembly

3. Collimator

4. Couplers

5. Fiber loop

6. Sensor head region

7. Power meter sensor

8. Power meter

9. Computer

10. Power supply

11. Tablet

100. Using the fiber loop as the sensor region

101. Measurement of signal strength with a power meter without external force

102. Recording the measured value as system power

103. Measuring the signal strength within the external force with a power meter

104. Determination of the ratio of the measured new power to the system power

105. Calculation of ringdown time.

106. Processing of values via computer or tablet Detailed Description of The Invention:

Basically the invention of the components of the system; LED Light Source (1) optical lens mechanism (2), collimator (3), couplers (4), the fiber loop (5), the sensorhead region (6), the power meter sensor (7) power meter (8) computer (9), power supply (10) and tablet (11).

The invention relates to LED light source (1) having a center wavelength of 1550 nm. an optical lens assembly (2) used to send light with the lowest loss the collimator (3), which ensures the transmission of light without deviations in a specific direction, is from the collimator (3). fiber loop (5), which provides high-precision measurement by traveling the light pulse in the loop several times fiber loop (5) couplers (4), which allow it to be divided into ratios such as 99.9:0.1, 99: 1 or 90: 10. from the fiber loop (5). the strength of the signal from the power meter sensor (7). provides measurement with the help of power meter (8). power supply (10), which provides electrical supply of all electronic components in the system and the computer that processes the measured values by means of software according to the method of graphical analysis (9). or on the tablet (11).

Figure 2 shows the LED light source (1), power meter (8), power supply (10), fiber loop (5), couplers (4) power meter sensor (7) and tablet (11), which can be located in a portable box.

If the subject of the invention is the method of application of the system:

1. 1550 nm center wavelength LED light source (1), optical lens assembly (2), desired ratio of couplers (4) (99.9:0.1, 99:1, 90:10, etc.) a single-mode fiber loop (5) loop with a power meter (8), a power meter sensor (7), and a computer (9) is constructed using the FHDSS system (Figure 1).

2. After the plastic jacket layer of the selected fiber of different lengths is peeled off from one region of the fiber ring (5), this part is used as the sensor region with etching or without etching (Figure 1). 3. While no external force is applied on the sensor area, the power of the signal coming out of the fiber loop (5) is measured with a power meter (8) and recorded as system power.

4. When an external force is applied on the sensor area, the power of the signal coming out of the fiber loop (5) is measured with a power meter (8) and its ratio to the system power is calculated.

5. The ringdown time is calculated using the obtained power ratio value.

6. The pressure /strain measurement is performed by correlating the applied pressure/strain and the ringdown time change.

7. The FLRDS sensor system can be designed as a portable device as shown in Figure 2. The LED light source (1), the optical lens assembly (2) and the single mode fiber are combined into a single box. All electronic components are supplied with power supply (10).

8. 1. coupler (4) an even smaller amount of a very small signal sent to the fiber loop (5) by the 2. coupler (4) is sent to the power meter (8).

9. With the help of special software installed on the computer (9) or tablet (11), data is collected, processed and recorded.