Electro-optical integrated transmitter chip for arbitrary quadrature modulation of optical signals

An optical device, comprising:

• a first Mach-Zehnder modulator that produces a first output;
• a second Mach-Zehnder modulator that produces a second output;
• a third Mach-Zehnder modulator that produces a third output;
• a fourth Mach-Zehnder modulator that produces a fourth output;
• a first input splitter coupled to the first and second Mach-Zehnder modulators;
• a first phase shifter coupled to at least one of the first and second outputs;
• a first output combiner positioned to combine the first and second outputs from the first and second Mach-Zehnder modulators;
• a second input splitter coupled to the third and fourth Mach-Zehnder modulators;
• a second phase shifter coupled to at least one of the third and fourth outputs;
• a second output combiner positioned to combine the third and fourth outputs;
• wherein
• the first input splitter splits an incoming light having linear polarization state into two beams having the same polarization state, and
• the second input splitter splits an incoming light having linear polarization state into two beams having the same polarization state.

A method of producing an optical output, comprising:

• providing an optical device with first and second Mach-Zehnder modulators formed as part of a single planar chip made of electro-optical material;
• splitting an incoming light having linear polarization state into two beams having the same polarization state;
• producing a first output from the first Mach-Zehnder modulator;
• producing a second output from the second Mach-Zehnder modulator;
• and
• combining the first and second outputs to produce a combined output.

A method for dual polarization transmission, comprising:

• a polarization splitting of light having arbitrary polarization state into a first polarization beam and a second polarization beam each having linear polarization state, wherein polarization states of these beams are orthogonal to each other;
• splitting the first polarization beam into two beams having the same polarization state;
• splitting the second polarization beam into two beams having the same polarization state;
• providing a device that includes a first optical device with first and second Mach-Zehnder modulators, and
• a second optical device with third and fourth Mach-Zehnder modulators,
• the first and second optical devices being formed as part of a single planar chip made of electro-optical material;
• producing from the first optical device of a first output with a first polarization;
• producing from the second optical device a second output with a second polarization;
• combining the first and second outputs to produce a beam with two orthogonal polarization signals.