Frequency stabilized high brightness tapered amplifier and laser modules

For many applications a frequency stabilized beam source with high output power and a good beam quality is needed. Tapered lasers and amplifiers can provide a high output power, whereas they have a slightly lower beam quality than ridge lasers. In a single mode fiber (SMF) coupled module, the beam quality provided by the module is predetermined by the fiber. The technological progress of tapered lasers should allow a high enough coupling efficiency to give SMF coupled modules using a tapered laser or amplifier the potential for a higher output power than modules using a ridge laser. It will be shown how this potential can be exploited by using different coupling systems for example with cylindrical lenses either crossed or in combination with rotational lenses. The advantages, problems and coupling results of those systems will be illustrated. Two approaches of frequency stabilization will be shown. To stabilize a tapered amplifier the external cavity has been set up by a fiber bragg grating on the backside of the amplifier. A volume holographic grating, which is written in the fast axis collimation lens of the coupling system, was used to stabilize a tapered laser.