CN206573235U - A kind of sagnac interferometer temperature sensor based on optical fiber ring laser - Google Patents

Abstract

The utility model discloses a kind of sagnac interferometer temperature sensor based on optical fiber ring laser, it is characterised in that：The sagnac interferometer for the photonic crystal fiber for pouring into liquid alcohol containing one section of part is fused in wavelength division multiplexer, optoisolator, sagnac interferometer, light polarizer, the optical fiber ring laser resonator of 1*2 types fiber coupler composition.On the one hand the photonic crystal fiber that part pours into liquid alcohol plays a part of TEMP, on the other hand as optical filter.Using when, the photonic crystal fiber that one section of part is poured into alcohol is placed in the environment of different temperatures, utilize fiber spectrometer measure optical fiber ring laser output laser center wavelength, you can determine temperature.Using the modeling characteristic of laserresonator, with detectable signal is strong, signal to noise ratio is high, line width, high sensitivity the characteristics of, can be applied in all kinds of Practical Projects.

Description

A Sagnac Interferometer Temperature Sensor Based on Fiber Ring Laser

technical field

The utility model belongs to the technical field of optical fiber sensing, in particular to a Sagnac interferometer temperature sensor based on an optical fiber ring laser.

Background technique

There are many ways to measure temperature, and the traditional temperature measurement technology has been very mature in various fields, such as thermistor, semiconductor and other types of temperature sensors. However, in some special environments, such as high temperature, high pressure, flammability, explosion, strong electromagnetic field interference, etc., the above-mentioned traditional temperature sensors based on electrical signal measurement are greatly limited. At this time, the optical fiber temperature sensing system is gradually favored by people because of its unique advantages and superior performance.

The interferometric fiber optic temperature sensor is a phase modulation fiber optic sensor. It uses the interference fringes of some interferometers such as Mach-Zehnder interferometer, Fabry-Perot interferometer, and Sagnac interferometer to realize temperature sensing. When the temperature changes, the interference fringes will shift, and the temperature is measured by determining the central wavelength. However, since the commonly used light sources are all broadband light sources, the detection signal, that is, a specific resonance peak in the output spectrum, corresponds to a relatively weak light intensity. On the other hand, the contrast of the interference spectrum output by the interferometer is low, and the 3dB bandwidth of the resonant peak is large, so it is difficult to accurately determine the central wavelength of the resonant peak, resulting in a large temperature measurement error.

Contents of the invention

In order to solve the above-mentioned deficiencies in the prior art, the utility model provides a Sagnac interferometer temperature sensor based on a fiber optic ring laser, and the Sagnac interferometer is connected to the ring laser. On the one hand, the optical fiber interferometer plays the role of temperature sensing, and on the other hand, it acts as an optical filter, so that the central wavelength of the laser output laser is modulated by temperature. The temperature of the measured environment can be obtained by measuring the center wavelength of the laser output from the laser. The output laser of the laser has the characteristics of strong light and ultra-narrow line width, which provides a guarantee for the accurate determination of its central wavelength.

The technical scheme adopted by the utility model: a Sagnac interferometer temperature sensor based on an optical fiber ring laser, including a pump laser, a wavelength division multiplexer, an erbium-doped optical fiber, an optical isolator, and a Sagnac interferometer , Optical polarizer, 1*2 type fiber coupler, fiber optic spectrometer.

Among them, the output wavelength of the pump laser can be 980nm, and the corresponding wavelength division multiplexer can be a 980/1550nm fiber optic wavelength division multiplexer; the photonic crystal fiber partly filled with liquid alcohol is 5-10mm; the connecting fiber can be G .652, G.653, and G.655 single-mode fiber.

The beneficial effects of the utility model are:

1. On the one hand, the Sagnac interferometer plays the role of temperature sensing, and on the other hand, it acts as an optical filter, so that the central wavelength of the laser output laser is modulated by temperature.

2. Connect the Sagnac interferometer to the resonator optical path of the fiber ring laser to form a temperature sensing and measurement system based on the fiber ring laser. Since the laser output by the fiber laser has the characteristics of light intensity and ultra-narrow linewidth, it is conducive to the accurate determination of its central wavelength, which provides a guarantee for accurate measurement of the temperature of the measured environment, and finally can realize high-precision sensing and measurement of temperature.

Description of drawings

Below in conjunction with accompanying drawing and specific mode, the utility model is further described.

Figure 1 is a structural diagram of a photonic crystal fiber partially filled with liquid alcohol. Among them, Figure 1(a) shows the cross-sectional view in the longitudinal direction; Figure 1(b) shows the cross-sectional view in the transverse direction.

Fig. 2 is a schematic diagram of the temperature sensing structure of a Sagnac interferometer based on a photonic crystal fiber partially filled with liquid alcohol;

Fig. 3 is a schematic diagram of the application and implementation of the Sagnac interferometer temperature sensor based on the fiber ring laser.

In the figure: 1. 2*2 single-mode fiber coupler, 2. Photonic crystal fiber partially filled with liquid alcohol, 3. Pump laser, 4. Wavelength division multiplexer, 5. Erbium-doped fiber, 6. Optical isolator, 7. Optical polarizer, 8.1*2 type fiber coupler, 9. Fiber optic spectrometer.

detailed description

The left and right connection ends of the 2*2 single-mode fiber coupler (1) are respectively fused with the two ends of the photonic crystal fiber (2) partially filled with liquid alcohol to form a Sagnac interferometer, as shown in Figure 2; The two ports of the demultiplexer (4) are connected with the pump laser (3) and the erbium-doped optical fiber (5) respectively; the other end of the erbium-doped optical fiber (5) is connected with the optical circulator (6), and the optical circulator The other end of the device (6) is connected with the 2*2 single-mode fiber coupler (1), the other end of the 2*2 single-mode fiber coupler (1) is connected with the optical polarizer (7), and the optical polarizer (7 ) is connected with the 1*2 type fiber coupler (8), and the other end of the 1*2 type fiber coupler (8) is connected with the fiber optic spectrometer (9) and the wavelength division multiplexer (4) respectively, such as Figure 3; Then place the sensing Sagnac interferometer in different ambient temperatures for sensing measurements. Temperature changes will cause changes in the refractive index of the poured liquid, which will eventually cause the central wavelength of the laser output laser to drift . At the same time, the laser output by the fiber laser has the characteristics of high light intensity and ultra-narrow line width, which is conducive to the accurate determination of its central wavelength and the realization of high-precision temperature measurement.

Claims (2)

1. A Sagnac interferometer temperature sensor based on fiber ring laser, including pump laser, wavelength division multiplexer, erbium-doped fiber, optical isolator, Sagnac interferometer, optical polarizer, 1* Type 2 fiber optic coupler and fiber optic spectrometer, characterized in that the Sagnac interferometer includes 2*2 single-mode fiber couplers and photonic crystal fibers partially filled with liquid alcohol, wherein the 2*2 single-mode fiber coupling The left and right connecting ends of the device are respectively fused with the two ends of the photonic crystal fiber to form a Sagnac interferometer; the two ports of the wavelength division multiplexer are respectively connected with the pump laser and the erbium-doped fiber, and the erbium-doped fiber The other end of the optical isolator is connected to the optical isolator, the other end of the optical isolator is connected to the Sagnac interferometer, the other end of the Sagnac interferometer is connected to the optical polarizer, and the other end of the optical polarizer is connected to the 1* Type 2 fiber coupler is connected, and the other end of type 1*2 fiber coupler is connected with fiber optic spectrometer and wavelength division multiplexer respectively. 2. A Sagnac interferometer temperature sensor based on a fiber ring laser according to claim 1, characterized in that: the photonic crystal fiber partially filled with liquid alcohol is 5-10mm; the connecting fiber can be G.652 , G.653 and G.655 single-mode fiber.