Background: Optically Coherent vs' Differential Detection

1
Background Optically Coherent vs. Differential
Detection
Courtesy of M. Nazarathy
2
Building block for coherent and differential
detection The Balanced Detector
Proof
2
3
A pair of BALANCED DETECTORs in
quadratureimplements the MIXING PRODUCT
mixing product
3
4
Coherent Homodyne Receiver Front-End (e.g. for
QPSK)
Local Oscillator (LO)
4
5
Building block for coherent and differential
detection Balanced detector
Coherent Homodyne BPSK Receiver
5
6
Binary Differential Phase Shift Keying (B-DPSK)
DELAY INTERFEROMETER (DI)
6
7
Building block for coherent and differential
detection Balanced detector
QDPSK receiver front-end
7
8
Building block for coherent and differential
detection Balanced detector
QDPSK receiver front-end
8
9
Building block for coherent and differential
detection Balanced detector
QDPSK receiver front-end
I-DI
Q-DI
9