Schäfter+Kirchhoff fiber collimators of series 60FC-BC-Q are designed for dichroic beam combination and collimation. They posses two fiber receptacles, an integrated dichroic beam combinerand integrated quarter-wave plate. The fiber collimators of series 60FC-BC-Q are used when the wavelengths for combination are so different that they cannot be transmitted by a common single-mode or PM fiber.
An optics for each application
A large variety of optical designs allows that the optimum focal lengths for the individual sources you need can be selected for each application. All lenses are AR-coated.
The radiation of the two input fibers is collimated to a beam with a diameter in the range Ø 1 - 4 mm, respectively. Either an adjacent dichroic beam combining optics or a polarization beam splitter superimposes the two sources to a common beam. In this collimated beam a dichroic quarter-wave plate changes the state of polarization from linear to left-handed or to right-handed circular for both of the sources simultaneously. Finally the common beam is expanded to the desired diameters. Since the focal lengths can be chosen independently for the two input wavelenghts, the resulting collimated beam diameters can be chosen to differ. Or the focal lengths can be chosen in such a way so that they compansate for different fiber NAs. By defocussing one of the input channels, it is also possible to compensate for chromatic aberration of the output optics.
Adjustment of focus
All fiber collimators of seris 60FC-BC-Q are aligned for the specified wavelengths.
In case of need you can change the distance between fiber end-face and the first collimating optics by means of an eccentric key. The lens does not rotate when adjusting the focus. The final focus setting is locked by means of two radially arranged clamping screws. Additionally attachment optics can be mounted to the front of the collimator.
Optimum lens performance
The angled polish of connectors of type APC is considered by a pre-angled mechanical coupling axis that compensates the beam deflection and you can use the lens centrically. This minimizes aberrations simply resulting from a non-ideal beam path through the lens.
The fiber collimator can be equipped with FC PC (wide key*), FC APC (wide key*), SMA-905 (F-SMA), ST or LSA (compatible with fiber connectors type DIN, AVIO and AVIM) receptacles. In case of FC or LSA with a spring loaded ferrule the fiber coupler has an additional grub screw to increase pointing stability.
The fiber collimators are made of nickel silver, black anodized aluminum and stanless steel.
The collimators series 60FC-BC-Q all are compatible to the multicube™ system (microbench or cage system).
Besides these series 60FC-BC-Q fiber collimators there is the series 60FC-BC. These fiber collimators generate a common collimated beam for two sources. The polarization of the superimposed output beam is linear for both wavelengths.