Abstract: The subject-matter of the present invention is a wavelength-coded fiber Bragg grating pressure sensor 1 which is suitable, in particular, for use in the case of high pressures and temperatures in oil drill holes. The sensor principle according to the invention is based on the fact that the hydrostatic pressure of a liquid or gaseous medium 11 is converted with the aid of a transducer 1 into a longitudinal fiber elongation or fiber compression. The transducer 1 comprises a measuring or pressure cylinder 7a which exchanges pressure with the medium 11, and a reference cylinder 7b which is shielded from the medium 11 or oppositely pressure-loaded. Temperature-compensated transducers 1 with a temperature-independent Bragg wavelength &lgr;B can be realized by introducing a suitable temperature dependence of the mechanical prestressing of the pressure sensor fiber 3 by selecting the materials, lengths and arrangements of the fiber holder supports 5a, 5b.