Fiber optic sensor types, features and product introduction
The fiber optic sensor consists of a light source, an incident fiber, an exit fiber, a light modulator, a photodetector, and a demodulator. The basic principle is that the light of the light source is sent to the modulation area through the incident optical fiber, and the light interacts with the measured parameters of the outside in the modulation area, so that the optical properties (such as intensity, wavelength, frequency, phase, and normality change) become The modulated signal light is sent to the photodetector and demodulator through the outgoing fiber to obtain the measured parameter.
Optical fiber sensors can be divided into two categories according to the sensing principle: one is a light-transmitting type (non-functional type) sensor, and the other is a sensing type (functional type) sensor. In the optical transmission type optical fiber sensor, the optical fiber acts only as a transmission medium for light, and the feeling of the measured signal is completed by other sensitive components. In this sensor, the outgoing optical fiber and the incident optical fiber are discontinuous, and the A modulator is a sensitive component of a spectral change or a sensitive component of other nature.
In the sensing type optical fiber sensor, the optical fiber has both the sensitivity to the signal to be measured and the transmission of the optical signal, and the "sensing" and "transmission" of the signal are combined into one. Therefore, the optical fiber in such a sensor is continuous. Due to the different roles played by the fibers in the two sensors, the requirements for the fibers are different.
In the light-transmitting type sensor, the optical fiber only transmits light, and the communication fiber or even the ordinary multi-mode fiber can meet the requirements, and the sensitive component can be flexibly selected by using high-quality materials, so the sensitivity of such a sensor can be achieved. Very high, but requires more optical coupling devices, the structure is more complicated.
The structure of the sensing fiber sensor is relatively simple, and some coupling devices can be used less. However, the requirements for the fiber are relatively high, and it is often necessary to use a special fiber that is sensitive to the signal to be measured and has good transmission characteristics. So far, the majority of the actual use of the former, but with the improvement of the optical fiber manufacturing process, the sensing optical fiber sensor will also be widely used.
Optical fiber sensors can be classified into intensity modulation type, phase modulation type, polarization modulation type, frequency modulation type, and wavelength modulation type. To date, fiber optic sensors have been able to measure more than seventy physical quantities.
Fiber optic sensors offer unique advantages over traditional sensors:
(1) High sensitivity
Since light is an electromagnetic wave with a very short wavelength, its optical length is obtained by the phase of the light. Taking a fiber interferometer as an example, since the diameter of the fiber used is small, the optical length changes when subjected to a small mechanical external force or a temperature change, thereby causing a large phase change.
Assuming a 10 m fiber, a 1 °C change causes a phase change of 1000 ard. If the minimum phase change that can be detected is 0.01 ard, the minimum temperature change that can be measured is 10 ° C, and the sensitivity is high.
(2) Anti-electromagnetic interference, electrical insulation, corrosion resistance, intrinsic safety
Because the fiber optic sensor transmits information by using optical waves, and the optical fiber is electrically insulated and corrosion-resistant transmission medium, and is safe and reliable, it can be conveniently and effectively used in various large electromechanical, petrochemical, mine and other strong electromagnetic interference and easy. In a harsh environment such as burning and explosion.
(3) Fast measurement speed
Light travels at the fastest speed and transmits two-dimensional information, so it can be used for high-speed measurements. The analysis of signals such as radar requires a very high detection rate, which is difficult to implement by electronic methods, and can be solved by high-speed spectrum analysis of the diffraction phenomenon of light.
(4) Large information capacity
The signal to be measured is based on light waves, and the frequency of the light is extremely high. The frequency band accommodated is wide, and the same fiber can transmit multiple signals.
(5) Suitable for harsh environments
Optical fiber is a kind of dielectric material that is resistant to high voltage, corrosion and electromagnetic interference and can be used in harsh environments where other sensors are not suitable. In addition, the optical fiber sensing 嚣 also has the characteristics of light weight, small volume, flexible winding, wide measuring object, good reusability and low cost.
Fiber Optic Temperature Sensors - FOT-L-SD and Fiber Optic Temperature Sensors - FOT-L-BA is a class of fiber optic temperature sensors that are ideal for measuring temperature in extreme environments, including low temperature, nuclear environment, microwave and high intensity. RF, etc. The FOT-L combines all the great features you'd expect from an ideal sensor body. Therefore, such sensors provide high accuracy and reliable temperature measurement even under extreme temperatures and adverse conditions.
The main features of both FOT-L temperature sensors are completely immune to EMI and RFI, while they are small in size, built-in safety devices for hazardous environments, high temperature resistance, corrosion resistance and high accuracy. Based on fiber optic technology, sensors are inherently immune to EMI and RFI. The light sensor is not electronically active, so it does not emit or be affected by any type of EM radiation, whether it is microwave, RF or NMR.
Fiber Optic Pressure Sensor - FOP-M260, FOP-M260 Fiber Optic Pressure Sensor is a small-volume, high-precision sensor designed for the medical field. It is completely resistant to electromagnetic interference and is completely intrinsically safe to the human body. Widely used in cardiovascular, gastroenterology, pharmacology and other medical fields.
Fiber optic pressure sensor FOP-M260 specific parameters:
Pressure range: 300mmHg~300mmHg
System accuracy: ±3mmHg
Sensitivity thermal effect: <0.3mmHg/°C
Withstand voltage: 4500mmHg
Wire sheath: nylon sheath, outer diameter 0.9mm
Top terminal: bare unprotected / with protection / with gel protection / custom
Standard sensor length: 2m
Connector: SCAI, SCAI is an SCA connector with smart chip communication calibration data connected to the signal reading module