My Project For Attenuators Used In Optical Fibers

I am going to develop a project with attenuators used in optical fibers at home. Before making, I need to make clear the working principles for attenuators used in optical fibers, in other words, through which technologies can attenuators be applied into optical fibers.

Here are my understandings:

1, Air isolation technology

Light transmission in the fiber by the total reflection of the law constraints, can not be scattered out to maintain the strength of the relatively stable. And once it is separated from the fiber, in the fiber and fiber to join the air between the interval, the light will be scattered out, causing light attenuation. As the light from the ordinary fiber into the air scattering is very strong, so to control the attenuation of a certain range, we must ensure that the isolation distance and maintain the alignment of the two ends of the fiber. Through this principle can be made flange fixed attenuator and adjustable attenuator. Flange fixed attenuator using isolation attenuator, according to the curve to produce a certain thickness of the attenuation film, the attenuation film implanted in the flange, can play a fixed light attenuation effect. Flange type adjustable optical attenuator using mechanical rotation principle, through the mechanical rotation to adjust the distance between the two ends of the connector can make the light attenuation between 0 ~ 30dB.

2, Displacement dislocation technology, this method is the two fiber core of the micro-shift misalignment, so as to achieve the effect of power loss.

Through the use of ordinary pigtail, with the welding machine to the two pigtail core in the case of dislocation welding work, so that the light in the transmission process occurs in the core loss, the connector-type fixed attenuator, also known as on-line fixed attenuator.

3, Attenuation of fiber technology, according to the metal ions on the absorption of light, developed a mixed metal ion attenuation fiber, and ordinary fiber attenuation coefficient per kilometer, this attenuation fiber also has a fixed attenuation coefficient, but this attenuation The coefficient is not calculated in kilometers, but in millimeters. Will the attenuation of fiber into the ceramic ferrule? After a special process? Can be made of yin-yang fixed attenuator.

4, Absorption of glass method

The optically polished neutral absorbing glass sheet can also be applied to the fabrication of optical attenuators. The use of material absorption of light characteristics, made of sheet or strip of neutral dark glass, placed on the optical path, you can light intensity attenuation. The absorptive glass is distinguished by the transmittance T and the decay rate expressed in decibels. Transmittance T = transmitted light intensity / incident light intensity, decay rate η = 1 / T, decay rate in decibels β = 10 x logη = - 10 x logT, attenuation rate in decibels can be easily estimated The decay rate of the decay rate is the decay rate of the combined attenuator group, expressed in decibels. The sheet is made of a fixed attenuation value, and the strip is different depending on the attenuation of the different parts of the dark matter in its continuous increments. A single piece of sheet-shaped light-absorbing glass can be used to make a fixed attenuator. A plurality of sheet-shaped absorptive glasses can be made into a sub-configurable fader by roulette conversion, while the strip-shaped absorbing glass can be made into a continuously adjustable attenuator by continuous displacement.

5, Solid-state light attenuation technology

Air isolation and absorption of glass in the form of adjustable optical attenuator are using mechanical methods to complete the attenuation of the adjustable, and now also have a small amount of solid light attenuation technology, such as adjustable diffraction grating technology, MEMS technology, liquid crystal technology , Magneto-optical technology, planar optical waveguide technology.

After getting to know the theories of attenuators used in optical fibers, I have outlined a circuit that does not work. I have no ideas why it does not work or where something goes wrong.

So I need your help: how could the circuit be possible to make it correct and work well ? What is your idea ? Any of your ideas would be highly appreciated.

May someone would like to help ?

thanks in advance.