Bend radius for normal SMF...

Have a question or want to start a discussion? Post it! No Registration Necessary.  Now with pictures!

Threaded View
I suspect I'm good, from what I can find, but I'm not finding exactly  
what I'd like to find, so I'm going to ask here and see if anyone still  
reads the group while I'm at it...

I bought an ADC/Tyco Electronics MST-12MH00-A1500A fiber drop mostly for  
the cable, from ebay, since I couldn't find any more reasonable cost  
source for drop fiber. It's (from what I recall when researching before  
buying it) normal single-mode fibers in a loose tube, with the  
fiberglass rods on either side that make it drop cable and delightfully  
robust. Certainly will be harder to kink than normal cable.

It's an ADC/Tyco product, but uses Corning flat drop cable (made in  
2012.) All the current Corning flat drop cable documents I can find are  
for their newer bend-insensitive products, and don't actually admit to a  
bend radius anyway. The ADC/TE documentation is also not mentioning a  
bend radius, or much about the cable at all, really.

SFM28e+ claims to be good out to 1625 wrapped on a 60mm (diameter)  
mandrel (bare fiber)

Commscope flat drop claims to be good with an installed (radius) of 3.2  
inches/8.1cm. Not the brand I have, but the same type of cable, with a  
useful data sheet I can actually find.

I need to either put the cable in a 2" weatherhead with an effective  
radius of about 3.5 inches/8.5cm, or come up with some cockamamie scheme  
to give it a larger radius. This would only be installed radius - the  
weatherhead top pops off for pulling. The cable, tested at an end,  
physically does this fine. Given the mandrel-radius for the bare fiber  
test, I have to suspect that this will be fine - it's loose tube cable,  
the fibers will not be pinched.

Anyone with practical experience? I know it will be less affected at  
1310 where most of my stuff runs, but one piece may be used at longer  
wavelengths, and I'd like to sanity-check before I install it.

--  
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

Bend radius for normal SMF...
Hi,  

I remember reading that the standard smf 28 bare fiber has a bend radius of ~16mm and at this bend the fiber has a life of over 10years. Any jacketed fiber must have a bend radius greater than this.  

Of course there is also a minimum loss associated with bending but I don't suppose you have to really worry about that.  

Hope this helps.  

SY

Site Timeline