Correcting Unwanted Amplitude Modulation in Electro-optic Modulators

...............................................................................................1 Chapter 1: Gravitational Waves & LIGO.......................................................2 1.1 Gravitational Waves.....................................................................2 1.2 LIGO......................................................................................2 1.3 A Source of Noise............................................................................................4 Chapter 2: Electro-optic Modulators...........................................................5 2.1 The Electro-optic Effect................................................................5 2.2 Phase Modulation........................................................................7 2.3 Amplitude Modulation..................................................................8 2.4 Experimental Verification..............................................................9 Chapter 3: The Error Signal Generator .......................................................11 3.1 Basic Design of the Feedback Control Systems...................................11 3.2 Error Signal Generator: Mixer.......................................................11 3.3 Error Signal Generator: Attenuator..................................................13 Chapter 4: Actuators..............................................................................16 4.1 Two Possible Actuators...............................................................16 4.2 Faraday Rotator........................................................................16 4.3 Picomotor...............................................................................18 Chapter 5: Experimental Performance........................................................20 5.1 Experimental Set-up...................................................................20 5.2 Faraday Rotator Performance........................................................20 5.3 Picomotor Performance...............................................................21 Chapter 6: Conclusions...........................................................................22 References...........................................................................................23