RZ & NRZ Moduation in Optical fiber

[Adil Israr]

Hello Freinds,

can any one help me about modulation technique in optical fiber? which technique is used in optical fiber nw either NZR or RZ??

regards
Adil

 

[jiripolivka]

A typical modulation on optical fibers is on/off, so it is RZ- return to zero. Sometimes the light is sent all the time and detected at two levels- higher and lower, but the lower level is not a zero. Then you can talk about NRZ.

NRZ is typical in copper cables where you can send signals with alternating polarity, NRZ.

 

[Adil Israr]

Ya thanx but if u have any documents related to the topic plz share with me.
theses are intensity modulation in optical communication,, but which one is more preferred NRZ or RZ??

 

[jiripolivka]

I am not so familiar with the installed optical systems. In principle, you can use both methods , then convert into electrical signals for processing.

 

[Adil Israr]

Ya thanx but if u have any documents related to the topic plz share with me.
theses are intensity modulation in optical communication,, but which one is more preferred NRZ or RZ??

 

[dincay]

RZ modulation is used for long reach fiber communications, because light disperses in fiber and RZ modulation provides larger headroom for dispersion. However RZ modulation requires more bandwidth because actual pulse width is shorter than one period of data.
NRZ is classic on-off modulation. It is used for short reach fiber communications.

For a good document about fiber optical communication
Broadband Circuits for Optical Fiber Communication - Eduard Sackinger

First chapters have the information about modulations.

 

[Adil Israr]

sir thanks for your reply but i am unable to download the book though it isn't free anymore.and kindly if have any simulation regarding my thesis "RZ & NRZ Moduation"