Abstract: A device is used for generating error signals for regulating the optical alignment of two lightwaves in connection with coherent heterodyne reception and comprises a receiver device (2, 3, 4) arranged focused opposite a front face at the end of a lightwave fiber (7) in order to make possible the transmission of the received information lightwave through the lightwave fiber (7) to an optical waveguide coupler (6), which is connected via a further lightwave fiber (13) with a local laser (12) and via two further lightwave fibers (8, 9) with respectively one detector (10, 11) for generating at least one error signal (Sr). A piezoelectric deflection unit (5) acts on this front face of the lightwave fiber (7) located in the focusing area of the receiving device.

Abstract: In a single-frequency laser and amplifier system, the radiation of a single-frequency, diode-pumped solid-state laser, preferably of a low power microcrystal laser or a monolithic ring-laser consisting of rare-earth-doped or transition-metal-doped crystal or glass materials, is coupled into a semiconductor amplifier chip (preferably GaAlAs, InGaAs or InGaAsP). The material system and the epitaxial structuring of the amplifier chip are selected to adapt it to the emission wavelength of the solid-state laser, so that it amplifies the single-frequency radiation of the solid-state laser and therefore generates an output beam which is intensified with respect to the coupled-in laser radiation.