Polarization beam splitter for guided light

Claim 1

A polarization beam splitter for guided light produced on a substrate (14) comprising: a passive Y-junction (66) having an input and two outputs and which is able to separate or split into two waves of the same amplitude and in phase with one another, an input light wave reaching the input of the Y-junction and which is a combination of two guided optical modes, namely a transverse electric mode TE and a transverse magnetic mode TM, an active phase shifter (68) with two arms respectively having two inputs, which respectively extend the two outputs of the Y-junction and two outputs, said phase shifter being able to induce a phase shift F of the TE mode which is propagated in one of the arms with respect to the TE mode which propagates in the other arm and a phase shift -F of the TM mode which propagates in the said arm with respect to the TM mode propagating in the said other arm, the substrate being made from a material making it possible to induce opposite variations DN and -DN respectively on the refractive index associated with the TE mode and on the refractive index associated with the TM mode and, an active directional coupler (70), independent of the polarization and able to constitute a 3 dB coupler by an appropriate polarization of the electrodes (78,80,82) of said coupler and having two inputs, which respectively extend the two outputs of the phase shifter, as well as two outputs, in such a way that when the coupler constitutes a 3 dB coupler the TM mode of the input wave is obtained at one of the two outputs of the coupler and the TE mode of said input wave is obtained at the other output of the coupler by appropriately polarizing the electrodes (72,74,76) of the phase shifter.