Patent ID: 6912088

Claim:
A system for producing a presettable polarization mode dispersion, comprising: a first polarization splitter/combiner with a first port, a second port, a third port, and a fourth port, wherein an input signal received at the first port is split into two split signals that are in vertical polarization alignment with one another and coupled out the second and third ports, and wherein a first signal coupled into the second port and a second signal coupled into the third port are combined into an output signal that is coupled out of the fourth port; a second polarization splitter/combiner with a fifth port, a sixth port, a seventh, and an eighth port, wherein the fifth port is coupled to receive the first split signal from the second port and the sixth port is coupled to receive the second split signal from the third port, the first split signal and the second split signal being combined to provide a combined signal at the seventh port, and wherein a twisted signal presented at the eighth port is split into two signals that are coupled out of the fifth port and the sixth port; a delay element coupled between the third port and the sixth port; a twisting element coupled between the seventh port and the eighth port and producing the twisted signal, wherein a polarization main axis of the combined signal and a polarization main axis of the twisted signal are rotated towards one another by an appropriate angle.