Abstract: An untreated fiber section in an optical sensor fiber has a zone which is framed by surface-treated fiber sections, thus making it possible to determine, by metrology, a mixture of light modes in the untreated fiber section that depends on bending. This advantageously makes it possible to measure the bending in the optical sensor fiber in a very accurate manner. The optical sensor fiber may be used in sensor having a laser diode and a photodiode.

Abstract: Disclosed are a method and a device for detecting the impact of a pedestrian on a vehicle. According to the invention, the pressures and/or deformations caused by an impact are measured using a sensor mechanism (1) located on the bumper, a first criterion (19) for deciding whether an impact of a pedestrian has occurred is formed from the output signal (a) of the sensor mechanism (1) with the aid of an evaluation means (2), and a decision as to whether a protective system (3) is to be triggered is made in accordance with said first criterion. The decision to trigger is made conditional upon the existence of a second criterion which is determined by a physical principle that is different from the sensor mechanism (1). The decision to trigger the protective system (3) is made only if both criteria are met.