Integrated optical device adjustable as a polarization splitter by means of a Mach-Zehnder interferometer

Passive optical polarisation splitting device having a pre-adjustable polarisation splitting function for a predetermined wavelength of light, said device comprising:

• an input waveguide,
• a Mach-Zehnder interferometer connected to the input waveguide, the interferometer having two monomodal waveguide branches which diverge from each other to beyond their mutual interaction spacing and which subsequently merge again,
• a waveguiding output section connected to the interferometer, the output section including a bimodal waveguiding coupling section which branches asymmetrically into a first and a second outgoing monomodal waveguide, and
• a region of glassy polable material incorporated, at least locally, in one of the two waveguide branches of the Mach-Zehnder interferometer outside said interaction spacing, the glassy polable material in said region having a predefined degree of poling, which is adjustable by a process of thermal relaxation for providing an optical phase difference between the two waveguide branches of the interferometer, said phase difference being required for polarisation splitting in the waveguide output section.

Method for adjusting an adjustable passive Mach-Zehnder interferometer incorporated in an adjustable passive optical device, which device comprises an input waveguide, a Mach-Zehnder interferometer connected to the input waveguide and having two waveguide branches which diverge from each other to beyond their interaction spacing and which subsequently merge again, and a waveguiding output section connected to the interferometer, a region of glassy polable polymer material being incorporated, at least locally, in one of the two waveguide branches outside said interaction spacing, the glassy polable polymer material having a predefined degree of poling, which method comprises the following steps:

• launching a specific input signal into said input waveguide,
• continuously measuring and/or analyzing an output signal exiting from said output section,
• decreasing the degree of poling by heating the polable polymer material in said region to a temperature below the glass transition temperature of the polymer material, and
• fixing a degree of poling during heating of the polable polymer material by cooling of the polable polymer material in said region when a desired output signal is obtained.