Single mode fiber coupled tapered laser module with frequency stabilized spectrum

Laser modules for single mode fiber (SMF) coupling of frequency stabilized diode lasers are so far mainly realized with ridge lasers due to their good beam quality. Tapered lasers are beam sources with a beam quality which is nearly as good as that of a ridge laser but with a higher optical output power. Therefore they have the potential for a higher SMF-coupled power than ridge lasers. It will be shown how the radiation of a tapered laser or amplifier can be frequency stabilized and coupled into a SMF in a compactly build module. To couple a tapered laser different coupling systems, using cylindrical lenses either crossed or in combination with rotational lenses are possible. The advantages, problems and coupling results of those systems will be illustrated. For many applications it is necessary to stabilize the frequency of the laser. This can be achieved for example by a fiber bragg grating, written in the SMF in which the laser is coupled or by a volume holographic grating, applied to a lens in the coupling system. Another possibility is the use of a tapered amplifier, which is stabilized by a fiber bragg grating on the backside of the amplifier