modulation in optical comm

Status
Not open for further replies.
B

bramin19

Member level 1
Joined
Jan 18, 2011
Messages
36
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,512
what is the use of modulator in optical communication?



I studied that the data can be given to the LASER and the LASER can transmit light for binary 1 and no light for binary 0.
 

bramin19 said:
I studied that the data can be given to the LASER and the LASER can transmit light for binary 1 and no light for binary 0.
Click to expand...

You are right but it is only one of modulation schemas. It is called OOK (on-off keying). It is true that it is popular type of modulation in optical communication however there are some other. These schemas are used for improving spectral efficiency (multilevel modulation) or for decreasing required signal to noise ratio on the input of receiver (e.g. PSK with coherent detection) .
 




In OOK, the binary data will drive the laser. usually the binary data is at lower rate than the modulated carrier signal rate. will the laser and the photo detector work finely at those high frequencies?


will the light emitted by the pulse as input and a high frequency sinusoidal signal as input are same?
 


Well, You should remember that in optical communication a light is a carrier, i.e. a light has some frequency (very heigh), amplitude and phase. It is still a sinusoidal signal which can be modulated in a different ways.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…