Abstract: Optical-waveguide coils are used in rotation rate measuring instruments. To protect the optical-waveguide coil (1) from external influences, such as sound waves, pressure, and temperature changes, which may result in measurement errors, it is wound on a coil form (2) of soft elastomer under low tension. The coil unit so formed (1/2) is then placed in the annular groove (4) of a housing (3/5). Spacers at the coil form (2) position the coil unit (1/2) in the annular groove in such a way that the coil (1) is exactly in the middle of the annular groove (4). The remaining free space of the annular groove (4) is then filled with a sealing compound (6) in a vacuum. The sealing compound also spreads between the windings of the coil (1). It is preferably the same material as that from which the coil form (2) is made.