differences between FC/PC and FC/APC fiber optic connectors
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Posted by Oliwier Bonawenturski on September 20, 2006, 6:44 am
Please log in for more thread options I know what are geometrical differences between FC/PC and FC/APC, but My problem i different. What are losses in fiber optic computer network when I'm use FC/PC or FC/APC?? Is it importan what surface of head of fiber optic cable is used?? I'm working in CableTV and we use fiber optic cables tu send TV signal and second to internet. In CaTV is used FC/APC besause it have reflectance more favourable to send more power ( 8db ). What is effect in use FC/APC in fiber optic computer network?? Sorry for My english, i use it only a year ;-) | |||||||||||||
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Posted by Leslie Sox on September 24, 2006, 6:13 pm
Please log in for more thread options I work with APC fiber optic connectors and cables. Angled connectors are used to elminate back reflections in systems sensitive to errors, such as Video. When the laser light hits the angled end, it is reflected back into the side of the fiber, the cladding, and not back down the length of the fiber to cause problems. It's not good to mix and match PC and APC connectors, you are creating a big air gap, but for short distances and low loss situations it will work, but is not ideal. This is from ( http://www.fiber-optics.info/glossary-a.htm ) APC: Abbreviation for angled physical contact. A style of fiber optic connector with a 5=B0-15=B0 angle on the connector tip for the minimum possible backreflection. This is from: Lennie Lightwave's Guide to Fiber Optics ( http://www.jimhayes.com/lennielw/llguide.pdf) "Beginning with the ST and FC which had keyed ferrules, the connectors were designed to contact tightly, what we now call physical contact (PC) connectors. Reducing the air gap reduced the loss and back reflection (very important to laserbased singlemode systems ), since light has a loss of about 5% (~0.25 dB) at each air gap and light is reflected back up the fiber. While air gap connectors usually had losses of 0.5 dB or more and return loss of 20 dB, PC connectors had typical losses of 0.3 dB and a return loss of 30 to 40 dB. Soon thereafter, it was determined that making the connector ferrules convex would produce an even better connection. The convex ferrule guaranteed the fiber cores were in contact. Losses were under 0.3dB and return loss 40 dB or better. The final solution for singlemode systems extremely sensitive to reflections, like CATV or high bitrate telco links, was to angle the end of the ferrule 8 degrees to create what we call an APC or angled PC connector. Then any reflected light is at an angle that is absorbed in the cladding of the fiber." Oliwier Bonawenturski wrote: | |||||||||||||
>
> I know what are geometrical differences between FC/PC and FC/APC, but My
> problem i different. What are losses in fiber optic computer network
> when I'm use FC/PC or FC/APC?? Is it importan what surface of head of
> fiber optic cable is used?? I'm working in CableTV and we use fiber
> optic cables tu send TV signal and second to internet. In CaTV is used
> FC/APC besause it have reflectance more favourable to send more power (
> 8db ). What is effect in use FC/APC in fiber optic computer network??
>=20
> Sorry for My english, i use it only a year ;-)