Ultra-responsive phase shifters for depletion mode silicon modulators
First Claim
1. An optical modulator semiconductor device comprising:
- a substrate;
an optical waveguide disposed upon the substrate;
a p-type region of semiconductor material disposed within said optical waveguide, said p-type region having a p-type contact terminal;
an n-type region of semiconductor material disposed within said optical waveguide, said n-type region having an n-type contact terminal;
wherein said n-type region and said p-type region share a non-planar junction interface as viewed in a cross section taken perpendicular to a light propagation direction in said optical waveguide; and
wherein said non-planar junction interface is configured to form at least two p/n junctions disposed one over the other in a direction normal to the substrate, so as to enhance an overlap between an optical mode in said optical waveguide and said non-planar junction interface when said optical modulator semiconductor device is operational.
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Accused Products
Abstract
A novel phase shifter design for carrier depletion based silicon modulators, based on an experimentally validated model, is described. It is believed that the heretofore neglected effect of incomplete ionization will have a significant impact on ultra-responsive phase shifters. A low VπL product of 0.3 V·cm associated with a low propagation loss of 20 dB/cm is expected to be observed. The phase shifter is based on overlapping implantation steps, where the doses and energies are carefully chosen to utilize counter-doping to produce an S-shaped junction. This junction has a particularly attractive VπL figure of merit, while simultaneously achieving attractively low capacitance and optical loss. This improvement will enable significantly smaller Mach-Zehnder modulators to be constructed that nonetheless would have low drive voltages, with substantial decreases in insertion loss. The described fabrication process is of minimal complexity; in particular, no high-resolution lithographic step is required.
33 Citations
12 Claims
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1. An optical modulator semiconductor device comprising:
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a substrate; an optical waveguide disposed upon the substrate; a p-type region of semiconductor material disposed within said optical waveguide, said p-type region having a p-type contact terminal; an n-type region of semiconductor material disposed within said optical waveguide, said n-type region having an n-type contact terminal; wherein said n-type region and said p-type region share a non-planar junction interface as viewed in a cross section taken perpendicular to a light propagation direction in said optical waveguide; and wherein said non-planar junction interface is configured to form at least two p/n junctions disposed one over the other in a direction normal to the substrate, so as to enhance an overlap between an optical mode in said optical waveguide and said non-planar junction interface when said optical modulator semiconductor device is operational. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification