High speed lithium niobate polarization independent modulators

An optical modulator comprising:

• a substrate;
• first, second, and third electrically conductive electrodes formed substantially parallel to each other on the substrate, the first and third electrodes being coupled to a predetermined fixed potential, and the second electrode is coupled to receive an electrical driving voltage signal to form a travelling wave therealong;
• first and second lithium niobate optical waveguides formed on the substrate and oriented substantially parallel to each other, the first lithium niobate optical waveguide being located between the first and second electrodes and coupled at a first end thereof to receive an optical channel signal from a remote source, and the second lithium niobate optical waveguide is located between the second and third electrodes and coupled at a second end thereof for use in forming an output signal from the modulator;
• and
• cross splice/delay line means for interconnecting a second end of the first lithium niobate optical waveguide to a first end of the second lithium niobate optical waveguide for introducing a predetermined rotation of TE and TM modes in the optical channel signal so that polarization components at a second end of the second lithium niobate optical waveguide experience a same amount of phase modulation.

An optical modulator comprising:

• a substrate;
• first, second, third, fourth, and fifth electrically conductive electrodes formed substantially parallel to each other on the substrate, the second and fourth electrodes being coupled to a predetermined fixed potential, the first and fifth electrodes being coupled to receive a first electrical driving voltage signal to form a travelling wave therealong, and the third electrode being coupled to receive a second electrical driving voltage signal to form a travelling wave therealong;
• and
• the first and second lithium niobate optical waveguides formed on the substrate and oriented substantially parallel to each other, the first lithium niobate optical waveguide being coupled at a first end thereof to receive an optical channel signal from a remote source and is then divided into first and second optical paths which extend between the first and second electrodes and the second and third electrodes, respectively, before being coupled together at a second end thereof, and the second lithium niobate optical waveguide is divided at a first end thereof into first and second optical paths which extend between the third and fourth electrodes and the fourth and fifth electrodes, respectively, before being coupled together at a second end thereof to form an output channel signal from the modulator;
• and
• cross splice/delay line means for interconnecting a second end of the first lithium niobate optical waveguide to a first end of the second lithium niobate optical waveguide for introducing a predetermined rotation of TE and TM modes in the optical channel signal so that polarization components at a second end of the second lithium niobate optical waveguide experience a same amount of phase modulation.