Mopa laser system with back reflection protection

Abstract

The invention relates to a MOPA laser system having at least one laser oscillator (MO), which generates laser radiation at an emission wavelength (λ), and having an optical amplifier (PA) downstream the laser oscillator (MO) in the propagation direction of the laser radiation, which optical amplifier amplifies the laser radiation and thereby spectrally broadens it to a useful bandwidth (Δλ). It is an object of the invention to provide an improved MOPA laser system which is designed for a high power of the amplified laser radiation and which is insensitive to back-reflection. Unavoidable back-reflections should neither affect the output power of the optical amplifier (PA), nor lead to the destruction of the laser oscillator (MO) or other components of the system. This object is achieved by the invention in that an optical bandpass filter (BPF) is arranged between laser oscillator (MO) and amplifier (PA), which optical bandpass filter is transparent to laser radiation at the emission wavelength (λ), wherein those spectral components of the returning, that is, counter to the propagation direction, laser radiation impinging on the bandpass filter (BPF), which, in terms of wavelength, lie outside the passband (), are reflected at the bandpass filter (BPF) in the propagation direction.