The Laser Beam Combiner takes each beam, coupled into its individual polarization-maintaining singlemode fiber, and combines them together as a single output in a single polarization-maintaining fiber. This representative modular system combines up to four wavelengths in the 400–660 nm range. The individual laser power sources of each wavelength can be attenuated separately so that any desired power relationship can be obtained.
The fully optimized dichroics from Schäfter+Kirchhoff superimpose the individual laser beams and have a 0.3° wedge profile to avoid interference from back-reflected light (Etalon effect). Propagation through parallel plates causes a beam offset, which is corrected by a compensatory axial displacement of the laser beam couplers. An attenuator allows adjustment of the combined laser output.
The tilt adjustment and inner focussing mechanism of the laser beam couplers, as well as the tilt adjustment of the dichroics, provide all of the degrees of freedom needed for alignment.
The design ensures a highly stable structure that can be immediately and confidently put to discriminatory use.