1. Fiber Optic
Gyroscope
Boyang Zhang
Steven Wang

3. Open Loop Setup

4. Phase
Modulator
50/50
Splitter
20 km
loop
Laser
Detector

5. Improvements
- Fusion splice
- Length of fiber loop
- Isolator
- lock-in Amplifier
- Phase modulator

6. Closed-loop Setup

7. - Same old problem with the fiber
breaking issue (phase modulator)
- Working frequency of phase
modulator
- Lack of experience working with
Lock-in Amplifier
- Mach Zehnder interferometer
Difficulties

8. Mach Zehnder interferometer
50/50
Splitter
Phase
Modulator
Isolator

9. What We Learned
- General fiber optic skills: E-Poxy,
fusion splice, etc.
- The closed loop
- Free space power meter
- Deeper understanding of the Sagnac
effect

10. Result
- Our setup demonstrates the
Sagnac Effect to a certain extent.
- We observed a directional
change of voltage on the
oscilloscope.
- But, the PM still doesn’t work
very well.

11. Future advice
- Systematically test phase modulator
- Do not screw the polarization controller
too tight
- Do not throw away polished fiber heads
- Do not set the rotation device faster
than 3°/min
- Always ask Bryan for E-Poxy

12. Systematically test PM
Test power of
1. Fiber
2. Fiber with middle part uncoated
3. Phase modulator without urethane
4. Phase modulator with urethane
5. Test in Mach Zehnder Interferometer