Incremental Capacity Upgrade of Exisitng Fiber Optic Links - Mitre
Incremental Capacity Upgrade of Exisitng Fiber Optic Links - Mitre
Incremental Capacity Upgrade of Exisitng Fiber Optic Links - Mitre
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Highlight: How Does DPSK Work?<br />
• Transmitted data is encoded on the laser optical phase<br />
differentially between adjacent bits rather than in the amplitude.<br />
• Decoding at the receiver is done via an optical delay-and-add<br />
Mach-Zehnder Interferometer. Here’s how it’s done:<br />
Input DATA<br />
Binary ON/OFF keyed NRZ Data<br />
0 1 0 1 1 0 1 0 0 1 1 0 0 0 1 0<br />
Electrically Pre-Coded Data Out(0) 1 1 0 1 1 0 0 0 1 0 0 0 0 1 1<br />
DPSK Encoded <strong>Optic</strong>al<br />
Signal<br />
Shifted by Demodulator 1-bit<br />
Delay<br />
Demodulator DATA Out<br />
—<br />
ϕ=0<br />
ϕ=π<br />
© 2006, The MITRE Corporation
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