Optical modulator having a plurality of modulator segments
First Claim
Patent Images
1. A modulator apparatus comprising:
- a plurality of optical modulator segments sequentially disposed in an optical path of an optical carrier wave and configured to successively modulate the optical carrier wave responsive to an input electrical signal so as to obtain a modulated optical signal; and
,a plurality of segment drivers individually coupled to the plurality of modulator segments and configured to drive each of the optical modulator segments synchronously with propagation of the optical carrier wave therein in accordance with a limiting voltage transfer function that relates a driving voltage Vd applied to an optical modulator segment to a control voltage Vc provided to a corresponding segment driver in response to the input electrical signal, so that the driving voltage Vd transitions between a low voltage Vlow and a high voltage Vhigh when the control voltage Vc passes an offset voltage Vos that is specific to the optical modulator segment, and so that Vd=Vlow when Vc<
(Vos−
Vth), and Vd=Vhigh when Vc>
(Vos+Vth), wherein Vth is a threshold voltage defining the width of a voltage transition region about the offset voltage Vos.
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Abstract
An optical modulator apparatus may include a plurality of segment drivers, each segment driver having a unique offset voltage and driving but a portion or a segment of an electro-optical modulator. A modulating electrical signal may be applied to the segment drivers via a plurality of electrical delays. Parameters of the segment drivers may be selected so as to approximate a pre-defined transfer function, which may include a linear or a non-linear transfer function.
14 Citations
18 Claims
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1. A modulator apparatus comprising:
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a plurality of optical modulator segments sequentially disposed in an optical path of an optical carrier wave and configured to successively modulate the optical carrier wave responsive to an input electrical signal so as to obtain a modulated optical signal; and
,a plurality of segment drivers individually coupled to the plurality of modulator segments and configured to drive each of the optical modulator segments synchronously with propagation of the optical carrier wave therein in accordance with a limiting voltage transfer function that relates a driving voltage Vd applied to an optical modulator segment to a control voltage Vc provided to a corresponding segment driver in response to the input electrical signal, so that the driving voltage Vd transitions between a low voltage Vlow and a high voltage Vhigh when the control voltage Vc passes an offset voltage Vos that is specific to the optical modulator segment, and so that Vd=Vlow when Vc<
(Vos−
Vth), and Vd=Vhigh when Vc>
(Vos+Vth), wherein Vth is a threshold voltage defining the width of a voltage transition region about the offset voltage Vos. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of modulating an optical carrier wave by an electrical signal, the method comprising:
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a) propagating the optical carrier wave through a succession of optical modulator segments; and
,b) driving each of the optical modulator segments in accordance with a limiting voltage transfer function synchronized with propagation of the optical wave therein, wherein the limiting transfer function relates a driving voltage Vd applied to an optical modulator segment to a control voltage Vc defined by the electrical signal, so that the driving voltage Vd transitions between a low voltage Vlow and a high voltage Vhigh when the control voltage Vc passes an offset voltage Vos that is specific to the optical modulator segment, and so that Vd=Vlow when Vc<
(Vos−
Vth), and Vd=Vhigh when Vc>
(Vos+Vth). - View Dependent Claims (15, 16, 17, 18)
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Specification