The Fiber Port Clusters are compact opto-mechanical units that combine two fiber-coupled sources with differing wavelengths and then splits the combined radiation into multiple output fiber cables with high efficiency and variable splitting ratio.Optical Setup
The two input ports are fiber-coupled to PM fiber cables
. Polarizers define the input polarization which is necessary for a long term stable splitting ratio.
Two photo diodes right after each input port allow for a continuous monitoring of the radiation. The two differing input sources are superimposed either by means of a dichroic mirror (long pass) or by a polarization beam splitter followed by a dichroic wave plate.
Subsequently, the radiation splitting is achieved by using a cascade of rotary half-wave plates in combination with polarization beam splitters. By use of the rotary half-wave plates, almost any desired splitting ratio can be achieved.
At the output ports further polarizers are placed in order to define the polarization at output of the system.Fiber Couplers
A fundamental component of a Fiber Port Cluster is the Laser Beam Coupler
, which is the input into the opto-mechanical unit collimating the input radiation and, finally, couples the radiation back into the polarization-maintaining fiber cables. The stability
of the total Fiber Port Cluster is determined by the stability
of the laser beam coupler.