Laser Gyroscope - Revision history

Wenxin: /* Conclusion */

2025-04-28T10:31:47Z

Conclusion

← Older revision		Revision as of 18:31, 28 April 2025
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	In summary, we managed to construct a fiber-optic laser gyroscope that can clearly differentiate between CW and CCW rotations, and also different rotation rates. We also observed an increase in sensitivity when using a longer fiber spool, albeit limited by high noise floor which prevented us from reaching the expected ~600 times increase in sensitivity.		In summary, we managed to construct a fiber-optic laser gyroscope that can clearly differentiate between CW and CCW rotations, and also different rotation rates. We also observed an increase in sensitivity when using a longer fiber spool, albeit limited by high noise floor which prevented us from reaching the expected ~600 times increase in sensitivity.

	For possible improvements, the first would probably be to isolate the 20 km fiber spool from external sources of noise, for example coating the walls of the container with rockwool. Another improvement would be to construct a platform that spins using an electric motor, so that we can reliably keep the rotation rate constant. Beyond that, other possible measurements include measuring the long-term stability of the gyroscope, such that we can evaluate the Allan deviation of the ~~setup~~.		For possible improvements, the first would probably be to isolate the 20 km fiber spool from external sources of noise, for example coating the walls of the container with rockwool. Another improvement would be to construct a platform that spins using an electric motor, so that we can reliably keep the rotation rate constant. Beyond that, other possible measurements include measuring the long-term stability of the gyroscope, such that we can evaluate the Allan deviation of the gyroscope.

Wenxin at 10:31, 28 April 2025

2025-04-28T10:31:11Z

← Older revision		Revision as of 18:31, 28 April 2025
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	We suspect that the lower-than-expected increase in sensitivity is due to a high noise floor. While there are various factors such as detector noise, we think that the most significant factor might be environmental noise affecting the fiber spool. Going from a cladded 50m fiber spool to a uncladded 20 km spool, the laser gyroscope is sensitive enough that we observe fluctuations in the laser gyroscope voltage that coincides with conversations in the other side of the room.		We suspect that the lower-than-expected increase in sensitivity is due to a high noise floor. While there are various factors such as detector noise, we think that the most significant factor might be environmental noise affecting the fiber spool. Going from a cladded 50m fiber spool to a uncladded 20 km spool, the laser gyroscope is sensitive enough that we observe fluctuations in the laser gyroscope voltage that coincides with conversations in the other side of the room.


			==Conclusion==

			In summary, we managed to construct a fiber-optic laser gyroscope that can clearly differentiate between CW and CCW rotations, and also different rotation rates. We also observed an increase in sensitivity when using a longer fiber spool, albeit limited by high noise floor which prevented us from reaching the expected ~600 times increase in sensitivity.

			For possible improvements, the first would probably be to isolate the 20 km fiber spool from external sources of noise, for example coating the walls of the container with rockwool. Another improvement would be to construct a platform that spins using an electric motor, so that we can reliably keep the rotation rate constant. Beyond that, other possible measurements include measuring the long-term stability of the gyroscope, such that we can evaluate the Allan deviation of the setup.

Wenxin: /* Fourth Setup */

2025-04-28T10:14:53Z

Fourth Setup

← Older revision		Revision as of 18:14, 28 April 2025
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	Again, we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW" plot (not the "CCW" plot, as it seems like the laser gyroscope readout plateaued at several points), and estimate a conversion factor of 60(4) V/rad/s (again assuming we remained in the linear range). With rms voltage fluctuations of <math> V_{rms} </math> = 54.6 mV at zero rotation, we estimate that with the 20 km fiber spool, our setup is limited to measuring > 0.0009 rad/s, or 0.05 deg/s rotations.		Again, we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW" plot (not the "CCW" plot, as it seems like the laser gyroscope readout plateaued at several points), and estimate a conversion factor of 60(4) V/rad/s (again assuming we remained in the linear range). With rms voltage fluctuations of <math> V_{rms} </math> = 54.6 mV at zero rotation, we estimate that with the 20 km fiber spool, our setup is limited to measuring > 0.0009 rad/s, or 0.05 deg/s rotations.

	We suspect that the lower-than-expected increase in sensitivity is due to a high noise floor. While there are various factors such as detector noise, we think that the most significant factor might be environmental noise. Going from a cladded 50m fiber spool to a uncladded 20 km spool, the laser gyroscope is sensitive enough that we observe fluctuations in the laser gyroscope voltage that coincides with conversations in the other side of the room.		We suspect that the lower-than-expected increase in sensitivity is due to a high noise floor. While there are various factors such as detector noise, we think that the most significant factor might be environmental noise affecting the fiber spool. Going from a cladded 50m fiber spool to a uncladded 20 km spool, the laser gyroscope is sensitive enough that we observe fluctuations in the laser gyroscope voltage that coincides with conversations in the other side of the room.

Wenxin: /* Fourth Setup */

2025-04-28T09:30:23Z

Fourth Setup

← Older revision		Revision as of 17:30, 28 April 2025
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	Again, we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW" plot (not the "CCW" plot, as it seems like the laser gyroscope readout plateaued at several points), and estimate a conversion factor of 60(4) V/rad/s (again assuming we remained in the linear range). With rms voltage fluctuations of <math> V_{rms} </math> = 54.6 mV at zero rotation, we estimate that with the 20 km fiber spool, our setup is limited to measuring > 0.0009 rad/s, or 0.05 deg/s rotations.		Again, we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW" plot (not the "CCW" plot, as it seems like the laser gyroscope readout plateaued at several points), and estimate a conversion factor of 60(4) V/rad/s (again assuming we remained in the linear range). With rms voltage fluctuations of <math> V_{rms} </math> = 54.6 mV at zero rotation, we estimate that with the 20 km fiber spool, our setup is limited to measuring > 0.0009 rad/s, or 0.05 deg/s rotations.

	We suspect that the lower-than-expected increase in sensitivity is due to a high noise floor. While there are various factors such as detector noise, we think that the most significant factor might be environmental noise. ~~With the~~ 20 km spool, the laser gyroscope is sensitive enough that we ~~observed~~ fluctuations in the voltage ~~readings~~ that ~~coincided~~ with conversations in the other side of the room.		We suspect that the lower-than-expected increase in sensitivity is due to a high noise floor. While there are various factors such as detector noise, we think that the most significant factor might be environmental noise. Going from a cladded 50m fiber spool to a uncladded 20 km spool, the laser gyroscope is sensitive enough that we observe fluctuations in the laser gyroscope voltage that coincides with conversations in the other side of the room.

Wenxin: /* Third setup */

2025-04-28T08:34:05Z

Third setup

← Older revision		Revision as of 16:34, 28 April 2025
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	[[File:ThirdSetup_CCW_smallrotation.jpeg\|400px]]		[[File:ThirdSetup_CCW_smallrotation.jpeg\|400px]]

	Lastly, we would like to quantitatively infer how sensitive our laser gyroscope is. Sensitivity is defined as the smallest rotation rate that can be detected by our gyroscope setup. To measure this, first we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the first "CW/CCW" plot, and estimate a conversion factor of 42.2(2) mV/rad/s (assuming we remained in the linear range). We then calculate the root-mean-square voltage fluctuations of the laser gyroscope readings at zero rotation, at <math> V_{rms} = 1.26 mV ~~</math>~~. Therefore, we estimate that our setup is limited to measuring > 0.03 rad/s, or 1.7 deg/s rotations.		Lastly, we would like to quantitatively infer how sensitive our laser gyroscope is. Sensitivity is defined as the smallest rotation rate that can be detected by our gyroscope setup. To measure this, first we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the first "CW/CCW" plot, and estimate a conversion factor of 42.2(2) mV/rad/s (assuming we remained in the linear range). We then calculate the root-mean-square voltage fluctuations of the laser gyroscope readings at zero rotation, at <math> V_{rms} </math> = 1.26 mV. Therefore, we estimate that our setup is limited to measuring > 0.03 rad/s, or 1.7 deg/s rotations.

	== Fourth Setup ==		== Fourth Setup ==

Wenxin: /* Fourth Setup */

2025-04-28T08:33:46Z

Fourth Setup

← Older revision		Revision as of 16:33, 28 April 2025
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	As expected, we see that the 20km fiber spool laser gyroscope is much more sensitive to rotations, where it is clearly sensitive to rotation rates well below 0.01rad/s. In theory, from the larger spool radius and the longer fiber length, we expect a ~600 times increase in the phase shift sensitivity.		As expected, we see that the 20km fiber spool laser gyroscope is much more sensitive to rotations, where it is clearly sensitive to rotation rates well below 0.01rad/s. In theory, from the larger spool radius and the longer fiber length, we expect a ~600 times increase in the phase shift sensitivity.

	Again, we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW/CCW" plot, and estimate a conversion factor of 60(4) V/rad/s (again assuming we remained in the linear range). With rms voltage fluctuations of <math> V_{rms} </math> = 54.6 mV at zero rotation, we estimate that with the 20 km fiber spool, our setup is limited to measuring > 0.0009 rad/s, or 0.05 deg/s rotations.		Again, we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW" plot (not the "CCW" plot, as it seems like the laser gyroscope readout plateaued at several points), and estimate a conversion factor of 60(4) V/rad/s (again assuming we remained in the linear range). With rms voltage fluctuations of <math> V_{rms} </math> = 54.6 mV at zero rotation, we estimate that with the 20 km fiber spool, our setup is limited to measuring > 0.0009 rad/s, or 0.05 deg/s rotations.

	We suspect that the lower-than-expected increase in sensitivity is due to a high noise floor. While there are various factors such as detector noise, we think that the most significant factor might be environmental noise. With the 20 km spool, the laser gyroscope is sensitive enough that we observed fluctuations in the voltage readings that coincided with conversations in the other side of the room.		We suspect that the lower-than-expected increase in sensitivity is due to a high noise floor. While there are various factors such as detector noise, we think that the most significant factor might be environmental noise. With the 20 km spool, the laser gyroscope is sensitive enough that we observed fluctuations in the voltage readings that coincided with conversations in the other side of the room.

Wenxin: /* Fourth Setup */

2025-04-28T08:32:42Z

Fourth Setup

← Older revision		Revision as of 16:32, 28 April 2025
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	== Fourth Setup ==		== Fourth Setup ==

	Since we have a 20km fiber spool lying around, we decided to replace the 50m fiber spool with the 20km fiber spool, with a spool diameter of ~~~18cm~~.		Since we have a 20km fiber spool lying around, we decided to replace the 50m fiber spool with the 20km fiber spool, with a spool diameter of ~15cm.

	[[File:FourthSetup_image.jpeg\|400px]]		[[File:FourthSetup_image.jpeg\|400px]]
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	[[File:FourthSetup_CW&CCWslow.jpeg\|800px]]		[[File:FourthSetup_CW&CCWslow.jpeg\|800px]]

	As expected, we see that the 20km fiber spool laser gyroscope is much more sensitive to rotations, where it is clearly sensitive to rotation rates well below 0.01rad/s. In theory, from the larger spool radius and the longer fiber length, we ~~expected~~ a ~~~700~~ times increase in the phase shift sensitivity.		As expected, we see that the 20km fiber spool laser gyroscope is much more sensitive to rotations, where it is clearly sensitive to rotation rates well below 0.01rad/s. In theory, from the larger spool radius and the longer fiber length, we expect a ~600 times increase in the phase shift sensitivity.

	Again, we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW/CCW" plot, and estimate a conversion factor of 60(4) V/rad/s (again assuming we remained in the linear range). With rms voltage fluctuations of <math> V_{rms} = 54.6 mV ~~</math>~~ at zero rotation, we estimate that with the 20 km fiber spool, our setup is limited to measuring > 0.0009 rad/s, or 0.05 deg/s rotations.		Again, we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW/CCW" plot, and estimate a conversion factor of 60(4) V/rad/s (again assuming we remained in the linear range). With rms voltage fluctuations of <math> V_{rms} </math> = 54.6 mV at zero rotation, we estimate that with the 20 km fiber spool, our setup is limited to measuring > 0.0009 rad/s, or 0.05 deg/s rotations.

			We suspect that the lower-than-expected increase in sensitivity is due to a high noise floor. While there are various factors such as detector noise, we think that the most significant factor might be environmental noise. With the 20 km spool, the laser gyroscope is sensitive enough that we observed fluctuations in the voltage readings that coincided with conversations in the other side of the room.

Wenxin: /* Fourth Setup */

2025-04-28T08:21:07Z

Fourth Setup

← Older revision		Revision as of 16:21, 28 April 2025
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	[[File:FourthSetup_CW&CCWslow.jpeg\|800px]]		[[File:FourthSetup_CW&CCWslow.jpeg\|800px]]

	As expected, we see that the 20km fiber spool laser gyroscope is much more sensitive to rotations, where it is clearly sensitive to rotation rates well below 0.01rad/s. In theory, from the larger spool radius and the longer fiber length, we expected a ~700 times increase in the phase shift sensitivity. By correlating the peak values of the laser gyroscope readings and the phone gyroscope readings (note that we only applied this to the CW measurement, as the CCW laser gyroscope readings seems to have plateaued), we estimate a sensitivity of 60(5) V/rad/s. That's weird.		As expected, we see that the 20km fiber spool laser gyroscope is much more sensitive to rotations, where it is clearly sensitive to rotation rates well below 0.01rad/s. In theory, from the larger spool radius and the longer fiber length, we expected a ~700 times increase in the phase shift sensitivity.

	~~Based on~~ the laser gyroscope ~~noise~~ at zero rotation, we estimate ~~a minimum rotation rate of~~ 0.~~003rad~~/s, or 0.~~17deg~~/s ~~for us to pick up signals above the noise~~.		Again, we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW/CCW" plot, and estimate a conversion factor of 60(4) V/rad/s (again assuming we remained in the linear range). With rms voltage fluctuations of <math> V_{rms} = 54.6 mV </math> at zero rotation, we estimate that with the 20 km fiber spool, our setup is limited to measuring > 0.0009 rad/s, or 0.05 deg/s rotations.

Wenxin: /* Third setup */

2025-04-28T08:14:23Z

Third setup

← Older revision		Revision as of 16:14, 28 April 2025
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	[[File:ThirdSetup_CCW_smallrotation.jpeg\|400px]]		[[File:ThirdSetup_CCW_smallrotation.jpeg\|400px]]

	Lastly, we would like to quantitatively infer how sensitive our laser gyroscope is. Sensitivity is defined as the smallest rotation rate that can be detected by our gyroscope setup. To measure this, first we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW/CCW" plot, and estimate a conversion factor of 42.2(2) mV/rad/s (assuming we remained in the linear range). We then calculate the root-mean-square voltage fluctuations of the laser gyroscope readings at zero rotation, at <math> V_{rms} = 1.26 mV </math>. Therefore, we estimate that our setup is limited to measuring > 0.03 rad/s, or 1.7 deg/s rotations.		Lastly, we would like to quantitatively infer how sensitive our laser gyroscope is. Sensitivity is defined as the smallest rotation rate that can be detected by our gyroscope setup. To measure this, first we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the first "CW/CCW" plot, and estimate a conversion factor of 42.2(2) mV/rad/s (assuming we remained in the linear range). We then calculate the root-mean-square voltage fluctuations of the laser gyroscope readings at zero rotation, at <math> V_{rms} = 1.26 mV </math>. Therefore, we estimate that our setup is limited to measuring > 0.03 rad/s, or 1.7 deg/s rotations.

	== Fourth Setup ==		== Fourth Setup ==

Wenxin: /* Third setup */

2025-04-28T08:13:42Z

Third setup

← Older revision		Revision as of 16:13, 28 April 2025
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	[[File:ThirdSetup_CWCCW_Imin&Imax.jpeg\|800px]]		[[File:ThirdSetup_CWCCW_Imin&Imax.jpeg\|800px]]

	~~Lastly, we would like to see how sensitive our laser gyroscope is.~~ With a slow CCW rotation, we can see that our setup ~~is sensitive to rotation~~ on the order of 0.1 rad/s or 5.7 deg~~/s. By correlating the peak measurements from the laser gyroscope and the phone gyroscope, we estimate a sensitivity of 42.2(2) mV/rad~~/s.		With a slow CCW rotation, we can see in the plot below, that our setup can observe rotations on the order of 0.1 rad/s or 5.7 deg/s.

	We can also look at the detection noise while the setup is not spinning, and estimate the smallest rotation that the laser gyroscope can sense above the detection noise. Based on the maximum fluctuations of the laser gyroscope readings when the setup is at rest (~3 mV), we estimate that our setup is limited to measuring > 0.07 rad/s, or 4.0 deg/s rotations.		[[File:ThirdSetup_CCW_smallrotation.jpeg\|400px]]

	~~[[File:ThirdSetup_CCW_smallrotation~~.~~jpeg\|400px]]~~		Lastly, we would like to quantitatively infer how sensitive our laser gyroscope is. Sensitivity is defined as the smallest rotation rate that can be detected by our gyroscope setup. To measure this, first we correlate the peak measurements from the laser gyroscope and the phone gyroscope in the "CW/CCW" plot, and estimate a conversion factor of 42.2(2) mV/rad/s (assuming we remained in the linear range). We then calculate the root-mean-square voltage fluctuations of the laser gyroscope readings at zero rotation, at <math> V_{rms} = 1.26 mV </math>. Therefore, we estimate that our setup is limited to measuring > 0.03 rad/s, or 1.7 deg/s rotations.

	== Fourth Setup ==		== Fourth Setup ==