Angle Polish connector

September 9, 2009 1:26 PM

Technical question about Fiber optic cables: Does anybody know why the only make Angle Polish Connectors for singlemode cable and not multimode. What is the purpose of an angle polish connector?

Any sources would be greatly appreciated.

posted by cheechman85 to Technology (4 answers total)

An angle-polished connector prevents light bouncing back down the cable from the face where the two faces meet. Any light reflected from the joint surface bounces out into the cladding - think of the angled joint where the two pieces of fibre meet as being a bit like a mirror. This is only necessary where back-reflection is an issue.

I'm not sure why these are only used for single mode cable, but I'd suspect it's to do with the fact that single mode cables are generally used for high-precision tasks where back-reflection is likely to be a concern.
posted by le morte de bea arthur at 1:53 PM on September 9, 2009

Single mode cables are likely used with single-mode lasers, which are more sensitive to feedback. The angled face prevents light entering the fiber to bounce back into the laser, destabilizing it.
posted by fatllama at 1:58 PM on September 9, 2009

The acceptance angle of a multimode fiber is much larger than that of single mode fiber. So rather than delivering the back reflection into the cladding and reducing the back transmission (as in the single mode case) you would probably make things worse by actually reflecting the light back into counter propagating guided mode of the multimode fiber...
posted by NoDef at 2:27 PM on September 9, 2009

Thank you very much guys...
posted by cheechman85 at 5:09 AM on September 10, 2009