numerical aperture of optical fiber cable

[Kavitha Seetharaman]

hello,

Can anyone help me out with the numerical aperture of optical fiber cables ?

I want to know the values or the range of values of the numerical aperture of any optical fiber cable ?

Is the value always greater than 1 ??

Thanks in advance..
kavitha

 

[unclejed613]

https://www.fiberopticstech.com/technical/numerical_aperture.php

looks like N.A. is always LESS than 1

 

[Kavitha Seetharaman]

Thanks

 

[jpanhalt]

That is a nice link.

Ironically, I just had fiber optic Internet installed and asked the installer some related questions.* The fiber that was used had a "goo" around it, which was removed prior to fusing. The installer mentioned that the cable is also available without the goo.

If the goo was silicone oil (RI = 1.4), then the N.A. would be expected to be <1. But what if the fiber did not have the goo? Then I presume air (RI =1) would be the interface, which would lead to a N.A. of >1.

So, I think to answer Kavitha's question with certainty, one would need to know the construction of the cable.

John

*My question was related to the effects of stress on the glass fiber. The effect of stress on glass is easily visible using a set of polarizing filters. The installer threw out the term, "microkinks," which may be related to that. I have not read much on this, I was just curious based on my prior experience with optics and glass blowing.

 

[Ramussons]

https://www.fiberopticstech.com/technical/numerical_aperture.php

looks like N.A. is always LESS than 1

Good Link.

How does on go about if the fibre is "graded" ? Any input on this?

Ramesh