To understand how fiber optic cables work, imagine an infinitely long drinking straw or flexible plastic tube. For example, imagine a pipeline that is several kilometers long. Now, suppose the inner wall of the pipe is covered with a total reflection mirror. Then, let's say you look in from one end of the pipe. At the other end, a few kilometers away, a friend of yours turns on a flashlight and shines into the pipe.
Because the inner wall of the pipe is a total reflector, the light from the flashlight will be repeatedly reflected on the inner wall of the pipe (even though the pipe may be twisted), and as a result, you will see the light on the other end. If your friend turns the flashlight on and off in Morse code, he can communicate with you through that conduit. This is the basic principle of fiber optic cables.
Optical fiber is the abbreviation of optical fiber, which is a light transmission tool that utilizes the principle of total reflection of light in fibers made of glass or plastic.
Optical fiber actually refers to a core made of transparent material and a cladding made of a material with a slightly lower refractive index than the core around it. The medium in which the optical signal propagates in the fiber core. It is generally a symmetrical cylinder with a multilayer dielectric structure consisting of a core, cladding and coating layers.
The principle of optical fiber communication is: at the transmitting end, the transmitted information (such as voice) is first converted into an electrical signal, and then modulated onto the laser beam emitted by the laser, so that the intensity of the light changes with the amplitude (frequency) of the electrical signal. And sent out through the optical fiber; at the receiving end, the detector converts the optical signal into an electrical signal after receiving it, and restores the original information after demodulation.
The end of the optical fiber sensing head is doped with Cr3+ ions to realize fluorescence emission during optical excitation. The length of the doped part of the fiber is 8-10 mm. The outer surface of the end fiber is also coated with a black body cavity for radiation temperature measurement. (At this time, the ratio of the length to the diameter of the optical fiber blackbody cavity is greater than 10, which can meet the requirement of constant apparent emissivity of the blackbody cavity). It is worth noting that avoiding or reducing the mutual interference between the fluorescent emission part and the thermal radiation part is very important to ensure the performance of the whole system. After analysis, it can be found that this interference is mainly manifested as: 1) The influence of the radiation background signal in the fluorescence signal on the detection accuracy of the fluorescence lifetime, 2) The effect of fiber surface coating on the fluorescence intensity, 3) The influence of Cr3+ ion doping in the fiber on the thermal radiation signal of the blackbody cavity.
started by susanbelly on 10 Mar 22
Because the inner wall of the pipe is a total reflector, the light from the flashlight will be repeatedly reflected on the inner wall of the pipe (even though the pipe may be twisted), and as a result, you will see the light on the other end. If your friend turns the flashlight on and off in Morse code, he can communicate with you through that conduit. This is the basic principle of fiber optic cables.
Optical fiber is the abbreviation of optical fiber, which is a light transmission tool that utilizes the principle of total reflection of light in fibers made of glass or plastic.
Optical fiber actually refers to a core made of transparent material and a cladding made of a material with a slightly lower refractive index than the core around it. The medium in which the optical signal propagates in the fiber core.
It is generally a symmetrical cylinder with a multilayer dielectric structure consisting of a core, cladding and coating layers.
The principle of optical fiber communication is: at the transmitting end, the transmitted information (such as voice) is first converted into an electrical signal, and then modulated onto the laser beam emitted by the laser, so that the intensity of the light changes with the amplitude (frequency) of the electrical signal. And sent out through the optical fiber; at the receiving end, the detector converts the optical signal into an electrical signal after receiving it, and restores the original information after demodulation.
The end of the optical fiber sensing head is doped with Cr3+ ions to realize fluorescence emission during optical excitation. The length of the doped part of the fiber is 8-10 mm. The outer surface of the end fiber is also coated with a black body cavity for radiation temperature measurement. (At this time, the ratio of the length to the diameter of the optical fiber blackbody cavity is greater than 10, which can meet the requirement of constant apparent emissivity of the blackbody cavity). It is worth noting that avoiding or reducing the mutual interference between the fluorescent emission part and the thermal radiation part is very important to ensure the performance of the whole system.
After analysis, it can be found that this interference is mainly manifested as:
1) The influence of the radiation background signal in the fluorescence signal on the detection accuracy of the fluorescence lifetime,
2) The effect of fiber surface coating on the fluorescence intensity,
3) The influence of Cr3+ ion doping in the fiber on the thermal radiation signal of the blackbody cavity.