What will a blue UPC or a green APC connector reduce?

What will a blue UPC or a green APC connector reduce?

• A. Fresnel reflection
• B. Attenuation
• C. Dispersion
• D. Backscatter

Answer: (A)

End-face geometry at the connector controls how much light is reflected back toward the transmitter. Angled physical contact connectors (green APC) use an end-face that is tilted, so any light that reflects off the boundary between the fiber and the air (a Fresnel reflection) is deflected away from the fiber core and the source. This greatly reduces the amount of light that is sent back down the line, i.e., back-reflection. That reflected light comes from the Fresnel reflection at the end-face due to the refractive index difference. By tilting the facet, the reflected ray does not couple back into the fiber, which is why APC connectors are used where low back-reflection is important. Attenuation and dispersion are properties of the fiber and the propagation of the signal rather than the end-face reflection, and backscatter refers to light scattered backward within the fiber rather than the direct reflection at the interface. So the key effect of blue UPC and green APC types is to reduce Fresnel reflection.

End-face geometry at the connector controls how much light is reflected back toward the transmitter. Angled physical contact connectors (green APC) use an end-face that is tilted, so any light that reflects off the boundary between the fiber and the air (a Fresnel reflection) is deflected away from the fiber core and the source. This greatly reduces the amount of light that is sent back down the line, i.e., back-reflection.

That reflected light comes from the Fresnel reflection at the end-face due to the refractive index difference. By tilting the facet, the reflected ray does not couple back into the fiber, which is why APC connectors are used where low back-reflection is important. Attenuation and dispersion are properties of the fiber and the propagation of the signal rather than the end-face reflection, and backscatter refers to light scattered backward within the fiber rather than the direct reflection at the interface. So the key effect of blue UPC and green APC types is to reduce Fresnel reflection.