A new fiber optic, pulse pressure sensor with a Bragg grating, in the structure of which the operating principle of the
Hopkinson bar is applied, is presented in the paper. The delivery of the measured pressure to the sensor is realized by
means of a measuring head with truncated cone, made of silica glass and fusion-spliced to the grating's fiber. The optical
and the electronic setup of the sensor is given. The sensor was employed to measure pulse pressure generated by an
electric discharge in water. The obtained measurement results and the conclusions arising from them are presented.
The article presents the influence of the length of fiber Bragg grating with linear changeable period on processing accuracy of impulsive excitations acting along the longitudinal fiber axis. Using transfer matrix method the power reflectivity spectrums caused by impulsive strains are obtained. On this basis, assuming that grating's output signal is of centroidal frequency, the mean square error was evaluated as a function of the ratio of the length of the grating to the length of impulse, for different shapes of impulsive strains.
A new impulsive pressure sensor based on the elastic bar, is presented in this paper. As the elastic bar a piece of single mode optical fiber with photo-inscribed Bragg gratings is used. The grating is an optical strain gauge that converts the stress waves in the fiber into the changes of the Bragg wavelength. Experimental setup for the proposed sensor is demonstrated. The sensor was used to measure the pressure produced by an electric discharge in water.
In the paper the results of simulation and experimental investigation are presented of an optical frequency discriminator with an apodized, fiber Bragg grating of a constant period, cooperating with an identical grating of the sensor. Assuming the nonlinearity of the discriminator's conversion characteristic not greater than 1%, a conversion range of 0.30 nm was achieved, for gratings with a 3 dB bandwidth of 0.45 nm. Discriminators of such a type can be useful in many problems of dynamic measurements of mechanical quantities. Their certain inconvenience is the necessity of using an optical circulator, which is more expensive than a fiber optic coupler.