The principle of optical fiber transmission signal
Optical transmission between sender and receiver is transmitted in optical signal form of technology.The working process of the optical transmission of television signals is between the optical transmitter, optical fiber and optical receiver;In the room of the light of the input RF television signals into optical signals, it is composed of the electrical/optical converter (Electric - OpticalTransducer, E/O) completion, transform into optical signal by optical fiber transmission direction receiving equipment, optical receiver, optical receiver of the obtained from the optical fiber optical signal transform back into electrical signals.So the base principle of optical transmission signal is the whole process of electrical/optical and optical/electrical transformation, also known as the optical link.
Using light intensity modulation optical transmission methods at present.If use laser light hair device in phase of so-called coherent light, have taken the overall change of luminous intensity modulation method, which USES the optical output power corresponding to the change of the electrical/optical current transducer input signal and the characteristics of the linear change.
In Optical/electric converter (Optical - ElectricTransducer, O/E), the output current is proportional to input Optical signal strength, Optical/electric converter output current waveform and thus similar to electrical/Optical converter input current waveform, achieve the goal of the signal transmission.
So, what is how to guide the light signal optical fiber?Currently using cylinder is the optical fiber optical fiber cable TV system, it is composed of optical fiber cylinder and cladding, is quartz glass material.Cladding plays a closely enclosed the light in the optical fiber, protect the fiber core, enhance the strength of the fiber itself.The function of the fiber core is transmission optical signals.Fiber core and cladding are quartz glass material production and become, but in production when doping component is there a difference between the two, and thus lead to the refractive index produced by different sizes (fiber core is 1.463 ~ 1.463, the cladding was 1.45 ~ 1.46), and also related to the materials adopted by the different of course.When the laser emission light source into the fiber core, light incident to the cladding interface, as long as the Angle of incidence is greater than the critical Angle, would have a total reflection in the fiber core, shoot the light does not leak to the cladding, so get into the inside the fiber core optical signal will be continuously spread bottom go to,
Until the guided optical receiver.This process is the base of optical signals in the optical fiber transmission.
This paper released by Wan Shuo optoelectronic equipment co., LTD.