Applying draw tower FBGs to characterize fiber drawing processes

Fiber Bragg gratings (FBGs) inscribed during the fiber drawing (DTG) have an increased importance in the sensing market because of their outstanding properties, especially robustness, multiplex ability and efficient production of higher counts. A sensing system to characterize and optimize the DTG production process was developed and tested successfully. It uses the produced DTG itself as sensors to monitor drawing processes. The dynamic of drawing force variations and influences of different curing techniques at coating materials can be examined excellently with high time resolution. Analyzing the data on the variation of inscribed DTG Bragg wavelengths leads to optimization possibilities to decrease these variations. Temperature increases in the coating curing lamp were measured for different lamp powers. Because of a short throughput-time in the draw tower, a fast and multipeak interrogation unit was developed to get an appropriate dynamic time resolved measurement.