Apparatus and method for linearized cascade coupled integrated optical modulator
AssigneeCrystal Technology, Inc.
InventorHalvor Skeie
Life of this patent
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Abstract
A Y-branch type first interferometric modulator, and a coupler structure type second interferometric modulator are connected in cascade. The levels of DC bias voltages applied to the first and second interferometric modulators, respectively, are adjusted for maximizing the linearity of a modulated output light signal. The configuration of input and output coupler structures of the second interferometric modulator are predetermined for also contributing to maximizing the linearity of the output signal.
Claims23
An integrated electro-optical modulator for providing a linearly modulated light signal, comprising:
- a substrate;
- a plurality of Mach-Zehnder type interferometric modulators formed on said substrate and coupled in cascade, each of said modulators including a plurality of electrode means for continuous connection to a source of reference potential, for receiving a modulating voltage, and for continuous connection to a DC bias voltage, respectively;
- a first one in a chain of said cascaded modulators further including an input waveguide segment for receiving an input light signal;
- and
- a last one of the chain of said cascaded modulators including an output waveguide segment providing an output light signal, whereby the levels of said DC bias voltages are predetermined for maximizing the linearity of a modulated output light signal.
The integrated electro-optical modulator of claim wherein said plurality of Mach-Zehnder type interferometric modulators includes a combination of cascaded coupler structure type, Y-branch type, and 2X1 switch type interferometric modulators.
In an integrated electro-optical modulator for providing a linearly modulated light signal, a method for maximizing the linearity thereof comprising the steps of:
- forming a first Mach-Zehnder type interferometric modulator on a substrate as an input stage;
- forming a second Mach-Zehnder type interferometric modulator on said substrate as output stage coupled in cascade with said first modulator;
- applying first and second modulating voltages to said first and second modulators, respectively;
- continuously applying first and second DC bias voltages to said first and second modulators, respectively;
- and
- adjusting the levels of said first and second DC bias voltages, for maximizing the linearity of said integrated electro-optical modulator.
An integrated optical modulator for providing a linearly modulated light signal, comprising:
- a cascade of optical modulators formed on a substrate, each modulator having a plurality of electrode means for receiving a modulating voltage, and for continuously receiving a bias voltage, respectively;
- and
- means for continuously supplying bias voltage to said electrode means for linearizing a light output from the cascaded optical modulator as a function of said modulating voltage.
Dependencies are inferred from the claim text.