Integrated optics polarization beam splitter using form birefringence
A method for separating the orthogonal polarization components of an incident optical signal into two spatially separated output ports is described. The method comprises a Mach-Zehnder interferometer where one of the two branches has a section of waveguide that exhibits form-birefringence. This integrated optic Polarization Beam Splitter (PBS) is broadband, has high extinction ratio, and has characteristics that are tunable.
1. An optics polarization beam splitter for separating orthogonal components of an incident optical signal using an asymmetric Mach-Zehnder interferometer, comprising
an input optical coupler to split an incident optical signal, which has two orthogonal polarization states, into a first waveguide branch and a second waveguide branch wherein said first waveguide branch has a birefringent section that exhibits form birefrigence to separate said two orthogonal polarization states and is of core material selected from the group consisting of silicon oxynitride (SiON), silicon nitride, silicon oxycarbide, silicon (Si) and tantalum oxide-silica Ta 2 O 5: SiO 2 ); the upper cladding is of silica (SiO 2 ); and lower cladding is of thermal oxide; and
an output optical coupler to combine the optical signals outputted from said first waveguide branch and said second waveguide branch and to output two orthogonal output optical signals, wherein said two orthogonal polarization states are transverse electric (TE) mode and transverse magnetic (TM) mode.
2. An optics polarization beam splitter for separating orthogonal components of an incident optical signals using an asymmetric Mach-Zehnder interferometer, comprising
an input optical coupler to split an incident optical signal, which has two orthogonal polarization states, into a first waveguide branch and second waveguide branch wherein said waveguide branch has birefringent section that exhibits form birefringence to segregate said two orthogonal polarization states, and has a core material deposited by a process selected from the group consisting of flame hydrolysis, sputtering, and chemical vapor deposition; and
an output optical coupler to combine the optical signals outputted from said first waveguide branch and said second waveguide branch and to output two orthogonal polarization output optical signals, wherein said birefringent section is coated with a birefringent layer.