**7. Discussion**

The piezo-optical transducer operation was studied in detail theoretically, experimentally, as well as with the help of accurate numerical simulation. In order to compare the main parameters of sensors based on different physical principles, expressions for the gauge factors of strain-resistive, piezoelectric and fiber-optic sensors were proposed and analyzed. Despite the high piezoelectric modules of new piezoelectric materials (electroactive polymers), the piezoelectric sensor gauge factors are similar to strain-resistive sensor gauge factors.

It was shown that the piezo-optical sensor gauge factor, in contrast to sensors of other types, depends on the sensor design and can be improved by optimizing the PE design. The PE cruciform shape allows stresses to be concentrated in its small working volume because fused quartz used has no plastic deformation and the compressive damage threshold is very high. The piezo-optical quartz sensor gauge factor (7389), obtained by numerical simulation of stresses and deformations in the PE, is confirmed by the experimental results (7340) and is two to three orders of magnitude greater than the gauge factors of sensors based on other physical principles.

**Table 2** shows that piezo-optical transducer is superior to the known industrially usable strain gauges. The high sensitivity of the piezo-optical sensor opens up new possibilities in problems of deformation measuring and stress analysis. For example, the use of only one such sensor makes it possible to control all parameters of the elevator movement: acceleration and deceleration, jerk, vibration, sound, according to International standard ISO 18738-1:2012 (E) Measurement of ride quality — Part 1: Lifts (elevators), as well as friction between the elevator car and the rails [45].


#### **Table 2.**

*Comparison of some basic strain sensors parameters.*

#### *Piezo-Optical Transducers in High Sensitive Strain Measurements DOI: http://dx.doi.org/10.5772/intechopen.94082*

The sensor can be used in all cases where winch mechanisms are used, for example, in mines, escalators, moving walks, conveyors, cranes, etc.

Due to its high sensitivity, the sensor can be used for remote deformation monitoring by mounting at a certain distance away from the measured deformations zone: in bridge structures, cars and railway wagons weight remote control, liquids and gases flow control.
