Silicon double-injection electro-optic modulator with insulated-gate and method of using same
First Claim
1. Apparatus for changing the refractive index of a light transmitting semiconductor waveguide having a longitudinal axis comprising:
- (a) a light transmitting semiconductor waveguide;
(b) injection means for producing a flow of free carriers along a carrier conduction channel within said light transmitting semiconductor waveguide; and
(c) gate control means for controlling the effective cross-sectional area of said carrier conduction channel by inducing at least one depletion region within said light transmitting semiconductor waveguide.
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Accused Products
Abstract
A double-injection transistor structure with an MOS gate is utilized as a guided-wave electro-optic phase modulator at infrared wavelengths in a silicon-on-insulator (SOI) waveguide. Cathode, gate and anode regions are integrated in the waveguide, longitudinally. The effective phase modulation is given by the voltage-variable overlap of the guided-mode optical field with carrier-induced local changes in the silicon refractive index. An electron-hole plasma is injected under the gate by cathode and anode. Using depletion-layer widening, the plasma channel width and mode overlap are controlled very rapidly by one or two low-power gate electrodes.
110 Citations
39 Claims
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1. Apparatus for changing the refractive index of a light transmitting semiconductor waveguide having a longitudinal axis comprising:
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(a) a light transmitting semiconductor waveguide; (b) injection means for producing a flow of free carriers along a carrier conduction channel within said light transmitting semiconductor waveguide; and (c) gate control means for controlling the effective cross-sectional area of said carrier conduction channel by inducing at least one depletion region within said light transmitting semiconductor waveguide. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of phase modulating a light beam comprising the steps of:
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(a) propagating a light beam along the longitudinal axis of a light transmitting semiconductor waveguide; (b) injecting a flow of free carriers into said light transmitting semiconductor waveguide, overlapping the lowest-order fundamental guided mode optical field of said light beam; (c) producing at least one depletion region within said light transmitting semiconductor waveguide adjacent to said flow of free carriers; and (d) altering the size of said depletion region for controlling the effective cross-sectional area of said flow of free carriers. - View Dependent Claims (21, 22, 23, 24, 25)
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26. An optical phase modulator comprising:
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(a) first and second carrier injection means formed with a semiconductor light propagating waveguide for forming an electron-hole plasma therein; (b) a direct current forward biasing first voltage source having a first terminal coupled to the first carrier injection means and a second terminal coupled to the second carrier injection means; (c) a second voltage source having a first terminal coupled to a gate electrode means positioned upon said semiconductor light propagating waveguide and a second terminal coupled to said waveguide for increasing at least one depletion zone therein upon the increase of voltage applied to said gate electrode means, thereby to alter the phase of light propagated through said semiconductor waveguide. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. Apparatus for changing the refractive index of a light transmitting semiconductor waveguide having a longitudinal axis comprising:
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(a) a light transmitting n type semiconductor waveguide; (b) injection means for injecting both holes and electrons along a carrier conduction channel within said light transmitting semiconductor waveguide; (c) gate control means for controlling the effective cross-sectional area of said carrier conduction channel by inducing at least one depletion region within said light transmitting semiconductor waveguide, and wherein said injection means comprises an anode electrode and a cathode electrode both mounted upon said light transmitting semiconductor waveguide, first voltage supply means electrically coupled between said anode electrode and said cathode electrode, and wherein said gate control means includes a gate electrode means, together with a gate control second voltage supply source electrically coupled thereto, said gate electrode means further comprising a p+/n junction formed within said waveguide. - View Dependent Claims (39)
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Specification