40m QIL Cryo_Lab CTN SUS_Lab CAML OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop

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Tue Jul 2 11:21:24 2013, Erica, DailyProgress, fiber optic, mode matching        Wed Jul 3 09:46:48 2013, Erica, DailyProgress, fiber optic, mode matching           Thu Jul 11 01:40:19 2013, Erica, DailyProgress, fiber optic, mode matching              Fri Jul 12 00:51:39 2013, Erica, Notes, fiber optic, mode matching                 Tue Jul 16 10:27:47 2013, Erica, Notes, fiber optic, mode matching, beam recombination                    Tue Jul 16 11:02:47 2013, Erica, Notes, fiber optic, mode matching, beam recombination                       Wed Jul 17 11:58:47 2013, Erica, Notes, fiber optic, mode matching, beam recombination                          Wed Jul 17 18:29:37 2013, Erica, DailyProgress, fiber optic, reducing drift in the recombined beam                             Sat Jul 20 23:39:09 2013, Erica, DailyProgress, fiber optic, reducing drift in the recombined beam                                Tue Jul 23 10:29:12 2013, Erica, DailyProgress, fiber optic, reducing drift in the recombined beam                                   Tue Jul 23 11:43:00 2013, Evan, DailyProgress, Electronics Equipment, Zach's op-amp recommendations                                   Fri Jul 26 11:07:44 2013, Erica, DailyProgress, BEAT, circuit for measuring temperature fluctations on CTN table                                      Fri Jul 26 11:22:45 2013, Erica, DailyProgress, BEAT, circuit for measuring temperature fluctations on CTN table                                         Fri Jul 26 11:45:28 2013, Erica, DailyProgress, BEAT, circuit for measuring temperature fluctations on CTN table                                            Mon Jul 29 13:30:26 2013, Erica, DailyProgress, BEAT, adding resistor, capacitor, and sockets                                               Tue Jul 30 12:23:41 2013, Erica, DailyProgress, BEAT, addressed noise problem, DC signal                                                  Thu Aug 1 00:25:02 2013, Erica, DailyProgress, fiber optic, insulating foam                                                     Fri Aug 2 12:38:41 2013, tara, DailyProgress, fiber optic, insulating foam                                                        Tue Aug 6 12:31:24 2013, Erica, DailyProgress, fiber optic, insulating foam                                                           Wed Aug 7 13:27:00 2013, Erica, DailyProgress, fiber optic, more foam, calculations for convertion from voltage to frequency                                                              Wed Aug 7 18:53:20 2013, Erica, DailyProgress, fiber optic, noise budget, Matlab notes.                                                                 Tue Aug 13 12:39:36 2013, Erica, DailyProgress, fiber optic, rewrote calculations for converting from voltage noise to frequency noise                                                           Tue Aug 13 12:28:20 2013, Erica, Notes, Electronics Equipment, new AD 590 circuit and its noise calculation, beam alignment                                                              Fri Aug 16 10:35:44 2013, Erica, Notes, Electronics Equipment, AD590 msrmt, conversion to freq noise                       Tue Jul 30 16:19:32 2013, Erica, Notes, fiber optic, setup for beam recombination                       Mon Aug 5 12:21:00 2013, Erica, Notes, fiber optic, calculation: phase change for fiber        Tue Jul 30 15:48:47 2013, Erica, DailyProgress, fiber optic, noise for GYRO

Message ID: 1282     Entry time: Tue Aug 6 12:31:24 2013     In reply to: 1276     Reply to this: 1284   1295 Author: Erica  Type: DailyProgress  Category: fiber optic  Subject: insulating foam

When we turned the laser back on today, the signal was oscillating pretty quickly. We taped white insulating sheets of foam with scotch tape around the spool of fiber so that was sealed. We placed a thicker grey sheet of foam underneath and on top of the spool. The top one was weighted down. Then we pulled down the drapes and let the setup sit, so everything would settle down after we disturbed it. After at least 30 minutes, the signal was oscillating even faster, a period was 7.5s. However, around 6:30pm, the signal had slowed down, so the period was around 80s. We took some data with the spectrum analyzer, pausing at the max and min and continuing whenever we hit a linear region so there was about 30 averages. Will include graph Once we have the noise budget, we'll have to measure various sources of noise and determine which sources cause what part of the noise budget. Types of noise: Temperature -> length Acoustic/Seismic Laser frequency drift We looked at possible circuits to measure the temperature fluctuations on the table, since the current circuit we have has an unaccounted DC value. This is one possible one. AD 587 is a voltage reference. There a low pass filter to get rid of the noise. The potentiometer is to match the 2 voltages goign into the op amp. The values are tentative as is the circuit itself. Got a reply from Thorlabs but they weren't very helpful. The core is doped silica but the doping information is proprietary. They gave me the spec sheet that can be found online as well as a graph displaying the relation between wavelength and attentuation.

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