Patent•
Enhanced silicon all-optical modulator
09 Feb 2009-
TL;DR: A single-photon absorption all-optical signal processing device, systems employing the same, and methods of making and using the same can be found in this paper, where examples are provided based on silicon semiconductor technology that employs rectangular waveguides fabricated on SOI wafers.
Abstract: A single-photon absorption all-optical signal-processing device, systems employing the same, and methods of making and using the same. Illustrative examples are provided based on silicon semiconductor technology that employs rectangular waveguides fabricated on SOI wafers. In some embodiments, it is observed that the waveguides have surface state density, σ, of not less than 1.5x1018 cm-1s-1mW-1 to provide a single-photon absorption operation mode. In some embodiments, some portion of the ridge waveguide structure has a surface to volume ratio of at least 18 μm-1, computed using a unit length of 1 μm of the waveguide, with the width and depth dimensions of the waveguide being measured in units of microns.
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Patent•
28 May 2009TL;DR: In this article, the authors describe all-optical processing devices that include patterned optically active polymers, such as organic polymers that interact with illumination at a first wavelength to change at least one optical property in a non-linear manner.
Abstract: All-optical processing devices that include patterned optically active polymers. The devices that are constructed according to principles of the invention include at least one optical input port and at least one optical output port, respectively configured to accept optical input signals and provide optical output signals. The devices include optically active material such as organic polymers that interact with illumination at a first wavelength to change at least one optical property in a non-linear manner. The optically active polymer can be placed adjacent one or more waveguides that allow the input illumination to propagate. As the optical property of the optically active material is changed by the incident illumination, the propagating illumination undergoes a modulation or change in phase, thereby providing an optical output signal having a desired relation to the optical input signal, such as the result of a logical or a computational operation.
31 citations
Patent•
27 Jun 2011TL;DR: A Mach-Zehnder interferometer can be configured as an optical device that provides a balanced output as discussed by the authors, where each device uses a silicon split or slotted wave guide having an electrooptically active material present within the slot.
Abstract: A Mach-Zehnder interferometer useful for analog or digital optical signal manipulation. In one example, the MZI is configured as an optical device that provides a balanced output. In another example, the MZI is configured as an optical device that provides a single ended output. Each device uses a silicon split or slotted wave guide having an electro-optically active material present within the slot. The balanced output device uses two slotted wave guides in push-pull configuration.
25 citations
Patent•
IBM1
TL;DR: In this article, a set of trenches in a precursor structure having a silicon substrate having a crystal direction, the silicon substrate substantially abutted by a first oxide, and a silicon germanium (SiGe) layer overlying the SiGe layer are formed.
Abstract: Various methods include: forming a first set of trenches in a precursor structure having: a silicon substrate having a crystal direction, the silicon substrate substantially abutted by a first oxide; a silicon germanium (SiGe) layer overlying the silicon substrate; a silicon layer overlying the SiGe layer; a second oxide overlying the silicon layer; and a sacrificial layer overlying the second oxide, wherein the first set of trenches each expose the silicon substrate and internal sidewalls of the first oxide; undercut etching the silicon substrate in a direction perpendicular to the crystal direction of the silicon substrate to form a cavity corresponding with each of the first set of trenches; and partially filling each cavity with a dielectric, leaving an air gap within each cavity connected with an air gap in an adjacent cavity.
16 citations
Patent•
19 Jan 2010TL;DR: In this article, an optical low drive voltage modulator electric field sensor is configured to provide an optical output signal at the modulated light output having an optical parameter responsive to an electric field at the electric field antenna.
Abstract: An optical low drive voltage modulator electric field sensor device includes an electric field antenna. A low drive voltage modulator has an electrical voltage input electrically coupled to the electric field antenna, a light input, and a modulated light output. The optical low drive voltage modulator electric field sensor is configured to provide an optical output signal at the modulated light output having an optical parameter responsive to an electric field at the electric field antenna. The optical low drive voltage modulator electric field sensor device can also be configured to provide an RF output signal at a location physically remote from said antenna, where the RF output signal is responsive to an electromagnetic wave received at a remote antenna.
4 citations
TL;DR: In this paper, the authors reviewed recent progress in optical waveguides, along with important technological developments in this field, and showed that the chip-scale solution provided by the silicon photonics is the most promising.
Abstract: Silicon on Insulator (SOI) waveguides are attracting considerable attention in recent years, and the devices based on these optical waveguides are important to realize many modern optical signal processing systems. The main driving forces behind these devices are the technological improvements in exploiting the non-linear optical phenomenon and their compatibility with CMOS devices. Although all optical signal processing devices have been investigated inten-sively, the chip-scale solution provided by the silicon photonics is the most promising. Silicon photonic devices are find-ing their applications in telecommunication transmission systems and biomedical instruments and in the new generation of high performance computing systems. Recent progress in patents all over the globe, along with important technological developments in this field are reviewed. Keywords: Nonlinear, optical waveguides, silicon-on-insulator (SOI), optical devices, integrated photonics, wavelength con-version, Raman laser, photodetector, four-wave-mixing (FWM), signal regeneration.
3 citations
References
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TL;DR: The p-i-n photodiode waveguide as discussed by the authors consists of an intrinsic waveguide 500 times250 nm where the optical mode is confined and two thin, 50nm-thick, doped Si wings that extend 5 mum out from either side of the waveguide.
Abstract: Submicrometer silicon photodiode waveguides, fabricated on silicon-on-insulator substrates, have photoresponse from <1270 to 1740 nm (0.8 AW-1 at 1550 nm) and a 3-dB bandwidth of 10 to 20 GHz. The p-i-n photodiode waveguide consists of an intrinsic waveguide 500times250 nm where the optical mode is confined and two thin, 50-nm-thick, doped Si wings that extend 5 mum out from either side of the waveguide. The Si wings, which are doped one p-type and the other n-type, make electric contact to the waveguide with minimal effect on the optical mode. The edges of the wings are metalized to increase electrical conductivity. Ion implantation of Si+ 1times10 13 cm-2 at 190 keV into the waveguide increases the optical absorption from 2-3 dBmiddotcm-1 to 200-100 dBmiddotcm-1 and causes the generation of a photocurrent when the waveguide is illuminated with subbandgap radiation. The diodes are not damaged by annealing to 450 degC for 15 s or 300 degC for 15 min. The photoresponse and thermal stability is believed due to an oxygen stabilized divacancy complex formed during ion implantation
175 citations
Patent•
11 Sep 1995TL;DR: A semiconductor optical waveguide device comprises a stripe-shaped semiconductor infrared waveguide, part of which is an active layer producing gain by electric current injection, and part of the semiconductor IR waveguide being an intra-band resonant absorption layer in which an IR resonant wavelength is arranged within the gain band of the active layer.
Abstract: A semiconductor optical waveguide device comprises a stripe-shaped semiconductor optical waveguide, part of the semiconductor optical waveguide being an active layer producing gain by electric current injection, and part of the semiconductor optical waveguide being an intra-band resonant absorption layer in which an intra-band absorption resonant wavelength is arranged within the gain band of the active layer, and means for injecting electric current into the active layer.
90 citations
TL;DR: High-speed all-optical switching via vertical excitation of an electron-hole plasma in an oxygen-ion implanted silicon-on-insulator microring resonator facilitates optical switching of signal light in the 1.55 mum wavelength range at modulation speeds larger than 5 Gbits/s.
Abstract: We demonstrate high-speed all-optical switching via vertical excitation of an electron-hole plasma in an oxygen-ion implanted silicon-on-insulator microring resonator. Based on the plasma dispersion effect the spectral response of the device is rapidly modulated by photoinjection and subsequent recombination of charge carriers at artificially introduced fast recombination centers. At an implantation dose of 1×1012 cm−2 the carrier lifetime is reduced to 55 ps, which facilitates optical switching of signal light in the 1.55 μm wavelength range at modulation speeds larger than 5 Gbits/s.
85 citations
Patent•
27 Feb 2007
TL;DR: In this article, a method and system for automatic feedback control of integrated optical quadrature modulator for generation of optical quaternary phase-shift-keyed signal in coherent optical communications is presented.
Abstract: The method and system are disclosed for automatic feedback control of integrated optical quadrature modulator for generation of optical quaternary phase-shift-keyed signal in coherent optical communications. The method comprises the steps of detecting at least a part of an output optical signal from the QPSK modulator, extracting of a particular portion of the output signal in frequency domain, and processing the signal in frequency domain to optimize the transmission of an optical link. The system and method of optical communications in fiber or free space are disclosed that implement the quadrature data modulator with automatic feedback control.
46 citations
Patent•
25 Apr 2006TL;DR: In this article, a fast silicon-on-insulator (SOI) waveguide-based optical device enhanced with minority charge carrier lifetime modifiers enables faster modulation speeds in optical attenuators, optical intensity/phase-modulators, and optical switches.
Abstract: A fast silicon-on-insulator (SOI) waveguide-based optical device enhanced with minority charge carrier lifetime modifiers enables faster modulation speeds in optical attenuators, optical intensity/phase-modulators, and optical switches whose operation principles are based on free-carrier injection into a waveguide. The waveguide is doped with gold (Au) or platinum (Pt) such that when a drive voltage (applied to the device) is turned off, the minority charge carriers rapidly annihilate because gold doping reduces the minority carrier lifetime, which improves transient characteristics of the optical device. Integration of the fast active device with passive devices such as WDM demultiplexers/multiplexers on the SOI optical waveguide platform enables realization of monolithic integrated optical components for advanced functionality such as dynamic spectral equalization.
29 citations