Abstract: The invention is a passively mode-locked ultrashort pulse fiber laser for generating ultrashort laser pulses, including a resonator in a figure-of-eight configuration, wherein the resonator has a main ring and a secondary ring optically coupled thereto designed as a non-linear Sagnac interferometer, and wherein the main ring and the secondary ring are constructed of polarization-maintaining optical fibers, and the main ring and/or secondary ring have a fiber section designed as a laser-active medium, wherein the laser-active medium is optically pumped through an externally-coupled pump light source which is also comprised, wherein the ultrashort pulse fiber laser is developed in that a separate optical unit is provided in the resonator as a dispersion compensation unit for compensating a group delay dispersion of the ultrashort laser pulses.

Abstract: The invention is a passively mode-locked ultrashort pulse fiber laser for generating ultrashort laser pulses, including a resonator in a figure-of-eight configuration, wherein the resonator has a main ring and a secondary ring optically coupled thereto designed as a non-linear Sagnac interferometer, and wherein the main ring and the secondary ring are constructed of polarization-maintaining optical fibers, and the main ring and/or secondary ring have a fiber section designed as a laser-active medium, wherein the laser-active medium is optically pumped through an externally-coupled pump light source which is also comprised, wherein the ultrashort pulse fiber laser is developed in that a separate optical unit is provided in the resonator as a dispersion compensation unit for compensating a group delay dispersion of the ultrashort laser pulses.

Abstract: The present invention is directed to a chirped dichroic mirror comprising a stack of alternating high refractive index and low refractive index layers, a front end portion including an antireflective coating followed by an impedance matching region in which the ratio of the optical thickness of a high refractive index layer to the optical thickness of the next following low refractive index layer is adiabatically increasing to a first value, the impedance matching region being followed by a chirped mirror region where the Bragg wavelength of the layer pair is generally increasing or generally decreasing, characterized in that the layers in a back end region form a second impedance matching region in which the ratio of the optical thickness of a high refractive index layer to the optical thickness of the next following low refractive index layer starts at the value of this ratio in the adjacent chirped mirror region and is then adiabatically decreasing in order to provide matched impedance to the surrounding m