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SIGNAL-TO-NOISE-RATIO (SNR) (Signal shot noise (quantum noise arising from…
SIGNAL-TO-NOISE-RATIO (SNR)
Signal shot noise
quantum noise arising from discrete nature of incident signal
photon absorption is non-continuous process
Number of absorption fluctuates statistically
Photocurrent fluctuation conforms to Poisson statistic
Means square noise current:
Dark current shot noise
arising from discrete nature of incident nature of photodiode dark current, Idark
current with no incident light
Dark current - buld dark current + surface leakage current
Mean square dark current shot noise:
Thermal noise
fluctuation due to random motion of electrons
arise from random thermal motion of carriers in resistive circuit elements
Means square thermal current:
SNR & detection sensitivity
ratio of signal urrent squared to total mean square noise current
total mean square noise current:
SNR:
the dominant noise component will determine the minimum detectable power, Pmin at the receiver/ the detection sensitivity of the detector
SNR for an APD
UMMI SHOBIRAH BINTI ALI
