Abstract: A narrowband laser transmitter which has a semiconductor laser and an external optical resonator coupled to the semiconductor laser so that the output power of the transmitter can be taken from the resonator, characterized by the laser transmitter being both a micro-optical realization or implementation as well as executed with a free beam propagation. To this end, the resonator is composed of an optical grating arrangement arranged in the beam path of the laser emission from the semiconductor laser and this optical grating arrangement will conduct one part of the supplied laser emission back to the semiconductor laser while conducting the other or second part of the emission to a coupling location at which the other part can be taken as the output power of the transmitter.

Abstract: A laser transmitter comprising a semiconductor laser, and an external resonator in the form of an optical directional coupler characterized by feedback device being allocated to a first waveguide of the directional coupler and also a second feedback device allocated to the second waveguide of the coupler, each of the feedback devices returning a portion of the radiant energy in their respective waveguides back along the waveguide to the directional coupler and the output power of the transmitter being taken from the second waveguide of the directional coupler. Preferably, the section of each of the waveguides between the directional coupler and the respective feedback means has a different length with the difference being substantially in the magnitude of the length of the semiconductor laser. Preferably, the waveguides are strip waveguides integrally formed on a substrate and can include a modulator, as well as having the semiconductor laser also integrated on the substrate.

Abstract: A narrow-band laser transmitter including a semiconductor laser and an external optical resonator in the form of a wavelength-selective fiber directional coupler. A partially reflecting feedback device is provided so that output power of the transmitter can be taken from the resonator. The frequency selective fiber directional coupler is formed by a dispersive double core fiber and the feedback device is supplied with radiant laser energy that is coupled over from one core into the other core and that portion of the radiant energy which has been coupled over is allowed to pass as output power of the transmitter by the feedback device.