Abstract
In this study a new algorithm for modulating a PZT stack using a sine-wave signal instead of a saw-tooth signal was developed in order to resolve the flyback problem in a PZT driver. An improved synthetic heterodyne demodulator circuit was designed and arranged to interrogate the output signal from an interferometric sensor with a sine-wave modulation (phase-generated carrier). A depth of modulation or a gain amplifier to the circuit design was adjusted such that the standard heterodyne signal could be formed. The result is a conventional PM modulated carrier that can be demodulated using standard techniques, followed by a lock-in amplifier or a phase meter, to recover the phase shift in the sensing information. Implementing it into a path-matching differential interferometer (PMDI) for the signal modulation validates this new method. The new synthetic heterodyne is applied to a differential optical fiber refractometer for measuring the refractive index change. A lock-in amplifier is chosen as the demodulator to extract the phase shift. Therefore, the resolution of this sensing system is 7.52 × 10-7 refractive index unit (RIU) in 120 μm length of the sensing cavity.
| Original language | English |
|---|---|
| Pages (from-to) | 15-22 |
| Number of pages | 8 |
| Journal | Proceedings of SPIE - The International Society for Optical Engineering |
| Volume | 4328 |
| DOIs | |
| Publication status | Published - 2001 |
| Event | Smart Structures and Materials 2001- Sensory Phenomena and Measurement Instrumentation for Smart Structures and Materials - Newport Beach, CA, United States Duration: 2001 Mar 5 → 2001 Mar 6 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering