Distance or power over fiber optic
I′m making a pcb to send some data over fiber and is my first design. I have no knowledge of fiber optics and communications on this. Now the problem I have is how can I tell how far can this communication. Anyone can recommend me some reading or similar to calculate distances on fiber types, wavelengths, power, etc..? Thank you.
greetings
The main factor while choosing optical fiber type is the distance: multimode (limited to roughly 5km), or single-mode (>5km) ..
Of course you can use single-mode for all applications, but multimode option (for <5km) is just more cost-effective ..
The rest is just basic Fiber Optic Budget Calculations (see attached TX budget sheet) and there’re plenty of examples on how to perform these estimations/calculations; google for “fiber+optical+budget” ..
Eg.
http://sensing.honeywell.com/index.c...ment/1/re_id/0
or
http://cc.uoregon.edu/cnews/summer2000/fiber.html
Also, there is a choice of devices for both most commonly used frequency ranges, namely 850nm (blue) and 1310nm(red), so select a pair (transmitter&receiver) that nicely fits into system power budget: transmitter power – link loss - receiver sensitivity + safety margin ..
Rgds,
IanP
Hi,
Thank you very much for your response. I am developing this module to my school and have never worked on optical fiber, but it seems to me interesting and so I have chosen this mode of communication. The problem is that no such estimate to say that the transmission reaches about 60km, 50km or whatever. So wondering if there is any relation to when to transmit, to windows, wavelengths, "Broadcast power?, Multimode or single mode, core diameter, etc., have to choose and how to calculate. I have read also that according to the distance to be calculated dispersion. This fiber is very new to me . Thank you very much.
Greetings
There are not many choices of diameters in multimode and single-mode ..
Multimode fiber can be 50, 62.5, and 100um, whereas single-mode is 8.5-10um ..
More about that stuff here:
http://www.arcelect.com/fibercable.htm
and here:
http://www.telebyteusa.com/foprimer/foch2.htm#2.4
As I said before, if the distance is more than 5km you choose single-mode cable, below that you can use any of them, but multimode is cheaper ..
What you do first is you estimate the distance; that gives you the number of dB that you loose over that distance ..
Then you add the loss of connectors at both ends (and possible splices or patch cables that you may have in the link, if none of those the loss is 0dB) ..
The next step is to go to manufacturer data sheets (for example Honeywell given in my previous post) and identify a pair (transmitter and receiver) that have enough power and sensitivity + safety margin of at least 3dB ..
That’s all ..
Rgds,
IanP