Pressure compensation of the temperature shift of the emission wavelength of a distributed-feedback laser

A new method of the emission wavelength stabilisation was proposed and developed for a holographic distributed-feedback laser with a dye solution. This method was based on pressure compensation of the temperature-induced change in the refractive index of the active solution. The compensation was achieved in a hermetically sealed two-section cell: one section was filled with the active dye solution and the other, separated from the former by a flexible impermeable membrane, was filled with a pressure-compensation liquid. A correct selection of the thermophysical characteristics of the components ensured that a temperature rise in both sections increased the pressure more rapidly in the active medium than in the absence of the compensator. This device made it possible to stabilise the refractive index of the active medium and to reduce the temperature drift of the emission wavelength by more than two orders of magnitude.