Once again I have a silly doubt and I would be thankful if someone clarifies in simpler terms..
when we represent binary data using voltage level, we represent 0 by certain voltage level and 1 by some other voltage-level (eg, as in case of NRZ-L) or may be by change of voltage and no change (e.g NRZ-I).
my doubt is:
In optical fiber, data is transmitted through pulses of light so, how 0s and 1s are represented in this case.
is this the right answer?
obtained from the link:
https://networkengineering.stackexchange.com/questions/22676/is-fiber-optic-digital-or-analog-optical-signal-is-digital-or-analog
Aparna Sathya Murthyto you
12 hours ago
Dear Priyadarshini
When we say light , it is a designed source such as laser or LED that takes the electrical signal (modulated or otherwise) and is fed (coupled) to a Optical fiber.
The simplest of modulation is OOK (on-off key) analogous to our amplitude shift keying(ASK) . Where certain voltage level (say 2 V) is represented as 1 and certain other (say 1 V) as 0. It is encoded (or modulated ) and fed to the light source (that flickers) for 0-1 patterns .
What is key here is coupling the light with least loss into the fiber core . For which the numerical aperture gives a area (like a cone) that helps match the laser beam width .
You can think like a flash light (the cone of light with some level darkness due to its head covering ) . In case of laser this is like line and hence least spreading .
Again the electrical voltage is the drive capacity (such as 0 to 2V ) or anything mentioned by the laser manufacturer .
It is a combination of electronic - Optical units for transmission and recovery . What travels is the modulated light pattern originating from the laser /LED and detected by a photo-detector that converts back to electrical . Again not all networks are OFC !!!!!!!
Rgds
Aparna
Priyadarsini Mishra
1 minute ago
Thank you so much madam!
So, in simple terms, the on and off of laser represents 1 and zero?
Once again thanks a lot.
Regards
Priyadarsini
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