Self-Repairing Packaged Strain Sensor With High Repeatability

We present experimental demonstrations of a self-repairing polymer waveguide strain sensor packaged in a polyimide capillary. The waveguide is fabricated between two multi-mode optical fibers through an ultraviolet curable resin and operates as a strain sensor by interrogation of the infrared power transmission through the waveguide. The packaging improves the performance of the sensor as compared to a previous unpackaged version, by removing previous “no-response” zones. The resulting sensor output is monotonic throughout the measurement range. The hysteresis in the sensor behavior among multiple loading cycles is also significantly reduced. A jump in the sensor output voltage is observed after the sensor self-repair process, which presents challenges for calibration of the sensor.