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Message ID: 158     Entry time: Tue Jul 7 16:49:05 2009
Author: Michelle Stephens, Connor Mooney 
Type: Laser 
Category: General 
Subject: Noise Measurements 

We used an SRS Spectrum Analyzer in parallel with an oscilloscope to measure various sources of noise in the 495 mW NPRO laser. We sent the beam into a PDA10CS photodetector and fed that signal to the spec analyzer and the scope. We measured the dark noise, and then the total noise at 2 mW, 4 mW, 7mW, and 9mW. We then did a theoretical calculation for the shot noise, as follows:

N = (Po*dt) / (h*f)

dN = sqrt(Po*dt / h*f)

dE = sqrt(h*f*Po*dt)

dI = dE*(Responsivity of PD)

dV = dI*(Gain of PD)

We plotted all three of these noise sources in matlab. The plot and the code are attached. The directories are:




Attachment 1: 495mW_NPRO_Noise.pdf  21 kB  | Hide | Hide all
Attachment 2: NPRONoise.m  1 kB  | Hide | Hide all
load -mat SRS003.MAT
load -mat SRS005.MAT
load -mat SRS006.MAT
load -mat SRS007.MAT
load -mat SRS008.MAT

h = 6.626E-34;
mu = 3E8/1.604E-6;
deltaT = 1.0;

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