# US 8,543,961 B2 · Computer implemented design of device for electro-optical modulation of light incident upon device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,543,961 B2 - Document ID: US8543961B2 - Status: Granted - Kind: B2 - Application number: 13/492,964 - Filed: 2012-06-11 - Published: 2012-09-27 - Granted: 2013-09-24 - Earliest claimed: 2008-11-10 - Assignees: International Business Machines Corporation - Applicants: Matthias Fertig; Nikolaj Moll; Thomas E. Morf; Thomas Pflueger - Inventors: Matthias Fertig; Nikolaj Moll; Thomas E. Morf; Thomas Pflueger - Web page: https://patentgrep.com/patent/US8543961B2 ## CPC - H10F 30/223: the potential barrier being a PIN barrier - B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals - G02F 1/015: based on semiconductor elements having potential barriers, e.g. having a PN or PIN junction (G02F1/03 takes precedence) - H04N 21/23424: {involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement} - H04N 21/42202: {environmental sensors, e.g. for detecting temperature, luminosity, pressure, earthquakes} - H04N 21/44016: {involving splicing one content stream with another content stream, e.g. for substituting a video clip} - H04N 21/44218: {Detecting physical presence or behaviour of the user, e.g. using sensors to detect if the user is leaving the room or changes his face expression during a TV programme (methods or arrangements for recognising human body or animal bodies or body parts G06V40/10; methods or arrangements for acquiring or recognising human faces, facial parts, facial sketches, facial expressions G06V40/16; methods or arrangements for recognising movements or behaviour G06V40/20; arrangements for identifying users in broadcast systems H04H60/45)} - G02F 1/0154: {using electro-optic effects, e.g. linear electro optic [LEO], Pockels, quadratic electro optical [QEO] or Kerr effect} - G02F 1/01708: {in an optical wavequide structure} - G02F 2201/124: interdigital - G02F 2201/305: diffraction grating - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method and apparatus for designing a device to operate in a coupling mode, a detection mode, or a reflection mode for incident light. The incident light has a wavelength λ and is incident upon a semiconductor structure of the device at an angle of incidence (θi). A voltage (V) is applied to the device. Each mode may be designed for an ON state and/or OFF state. For the coupling mode and detection mode, the ON state and OFF state is characterized by high and low absorption of the incident light, respectively, by the semiconductor structure in conjunction with the applied voltage V and angle of incidence θi. For the reflection mode, the OFF state and ON states is characterized by a shift in the optical path length of λ/2 and about zero, respectively, in conjunction with the applied voltage V and angle of incidence θi. ## Claims ### Claim 1 A method for designing an electro-optical modulator device to operate in a coupling mode or a detection mode in which light having a wavelength λ is incident upon a semiconductor structure comprised by the electro-optical modulator device at an incident angle (θi) with respect to a direction opposite to a Z direction, said method comprising: receiving input, by a processor of a computer system, for designing the electro-optical modulator device to operate in the coupling mode or the detection mode, wherein the semiconductor structure comprises a semiconductor layer having a thickness (r) in the Z direction and a plurality of grating structures on a top surface of the semiconductor layer, wherein the Z direction is perpendicular to the top surface of the semiconductor layer, wherein the semiconductor layer comprises a plurality of semiconductor channel regions, wherein the grating structures are distributed in a periodic pattern having a pitch (p1) in an X direction that is orthogonal to the Z direction, wherein each grating structure comprises a notch and is above a corresponding channel region of the plurality of semiconductor channel regions and has a height (hg) in the Z direction above the top surface of the semiconductor layer, wherein each notch comprises a width (w1) in the X direction, wherein a voltage V applied between each notch and a corresponding doped semiconductor region in the semiconductor layer induces a change Δa of an absorption coefficient (a) and a change Δn of an index of refraction of a semiconductor domain comprising each notch and its corresponding channel region to generate a changed absorption coefficient and a changed index of refraction of the semiconductor domain, and wherein said receiving input comprises receiving a value of λ, r, hg, an absorption coefficient threshold (Ath1), an index of refraction threshold (nth1), and acceptance criteria; said processor ascertaining P solution sets at which the electro-optical modulator device operates in an ON state in which V=V1 for causing the changed absorption coefficient to exceed Ath1 and causing the changed index of refraction to exceed nth1 and at which the acceptance criteria are satisfied, wherein said ascertaining comprises calculating Δa according to Δa(V) and calculating Δn according to Δn(V), wherein Δa(V) is a specified function of V and Δn(V) is a specified function of V, wherein each solution set of the P solution sets comprises p1, w1, θ1, and V1, and wherein P≧1; determining a design set for the ON state; said processor transmitting the design set for the ON state to an output device. ### Claim 2 (depends on 1) The method of claim 1, wherein said receiving input further comprises receiving a value of performance criteria, and wherein: if P=1 such that the P solution sets consist of a single solution set, then said processor determining the design set for the ON state comprises said processor determining the design set for the ON state as being the single solution set; if P>1, then said processor computing a performance count with respect to the performance criteria for each solution set and determining the design set for the ON state comprises said processor determining the design set for the ON state as being a solution set of the P solution sets having the highest computed performance count. ### Claim 3 (depends on 1) The method of claim 1, wherein θi is within a range defined by θi,min≦θi≦θi,max, wherein V is within a range defined by Vmin≦V≦Vmax, and wherein said receiving input further comprises receiving a value of θi,min, θi,max, Vmin, and Vmax. ### Claim 4 (depends on 1) The method of claim 1, wherein said receiving input comprises receiving a value of an absorption coefficient threshold (Ath0) and an index of refraction threshold (nth0), wherein the method further comprises determining that the electro-optical modulator device is switchable from the ON state to an OFF state and from the OFF state to the ON state by setting the applied voltage V to V1 for the ON state and to V0 for the OFF state, wherein V0 causes the absorption coefficient of the semiconductor domain to be less than Ath0 and the index of refraction of the semiconductor domain to be less than nth0, which defines a design combination of p1, w1, θi, and V0 for the OFF state, wherein Ath0n3 and n2>n1, wherein the semiconductor layer further comprises a plurality of doped semiconductor regions in an alternating sequence of channel regions in which each channel region comprises a second semiconductor material and is disposed between and in direct mechanical contact with a N+ doped semiconductor region of the plurality of doped semiconductor regions and a P+ doped semiconductor region of the plurality of doped semiconductor regions, wherein each grating structure further comprises a gate insulator disposed between and in direct mechanical contact with the notch and a corresponding channel region of the plurality of channel regions, and wherein the notch comprises a third semiconductor material. ### Claim 11 An apparatus comprising a computer program product, said computer program product comprising a computer readable memory device having a computer readable program code embodied therein, said computer readable program code containing instructions configured to be executed by a processor of a computer system to implement a method for designing an electro-optical modulator device to operate in a coupling mode or a detection mode in which light having a wavelength λ is incident upon a semiconductor structure comprised by the electro-optical modulator device at an incident angle (θi) with respect to a direction opposite to a Z direction, said method comprising said processor receiving input for designing the electro-optical modulator device to operate in the coupling mode or the detection mode, wherein the semiconductor structure comprises a semiconductor layer having a thickness (r) in the Z direction and a plurality of grating structures on a top surface of the semiconductor layer, wherein the Z direction is perpendicular to the top surface of the semiconductor layer, wherein the semiconductor layer comprises a plurality of semiconductor channel regions, wherein the grating structures are distributed in a periodic pattern having a pitch (p1) in an X direction that is orthogonal to the Z direction, wherein each grating structure comprises a notch and is above a corresponding channel region of the plurality of semiconductor channel regions and has a height (hg) in the Z direction above the top surface of the semiconductor layer, wherein each notch comprises a width (w1) in the X direction, wherein a voltage V applied between each notch and a corresponding doped semiconductor region in the semiconductor layer induces a change Δa of an absorption coefficient (a) and a change Δn of an index of refraction of a semiconductor domain comprising each notch and its corresponding channel region to generate a changed absorption coefficient and a changed index of refraction of the semiconductor domain, and wherein said receiving input comprises receiving a value of λ, r, hg, an absorption coefficient threshold (Ath1), an index of refraction threshold (nth1), and acceptance criteria; said processor ascertaining P solution sets at which the electro-optical modulator device operates in an ON state in which V=V1 for causing the changed absorption coefficient to exceed Ath1 and causing the changed index of refraction to exceed nth1 and at which the acceptance criteria are satisfied, wherein said ascertaining comprises calculating Δa according to Δa(V) and calculating Δn according to Δn(V), wherein Δa(V) is a specified function of V and Δn(V) is a specified function of V, wherein each solution set of the P solution sets comprises p1, w1, θi, and V1, and wherein P≧1; determining a design set for the ON state; said processor transmitting the design set for the ON state to an output device. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the apparatus comprises the computer system, and wherein the computer system comprises the computer program product. ### Claim 13 A method for designing an electro-optical modulator device to operate in a reflection mode in which light having a wavelength λ is incident upon a semiconductor structure comprised by the electro-optical modulator device at an incident angle (θi) with respect to a direction opposite to a Z direction, said method comprising: receiving input, by a processor of a computer system, for designing the electro-optical modulator device to operate in the reflection mode, wherein the semiconductor structure comprises a semiconductor layer having a thickness (r) in the Z direction and a plurality of grating structures on a top surface of the semiconductor layer, wherein the Z direction is perpendicular to the top surface of the semiconductor layer, wherein the semiconductor layer comprises a plurality of semiconductor channel regions, wherein the grating structures are distributed in a periodic pattern having a pitch (p1) in an X direction that is orthogonal to the Z direction, wherein each grating structure comprises a notch and is above a corresponding channel region of the plurality of semiconductor channel regions and has a height (hg) in the Z direction above the top surface of the semiconductor layer, wherein each notch comprises a width (w1) in the X direction, wherein a voltage V applied between each notch and a corresponding doped semiconductor region in the semiconductor layer induces a change Δa of an absorption coefficient and a change Δn of an index of refraction of a semiconductor domain comprising each notch and its corresponding channel region to generate a changed absorption coefficient (a), a changed index of refraction (n), and a change in an optical path length (ΔOPL) of the semiconductor domain, wherein ΔOPL=(2π/λ)*Δn*δr, wherein δr is a total physical path length of the semiconductor domain traversed by the light incident upon the semiconductor structure at the angle θi, and wherein said receiving input comprises receiving a value of λ, r, hg, an absorption coefficient threshold (Ath0), index of refraction thresholds (n0min and n0max) such that n0min1, then said processor computing a performance count with respect to the performance criteria for each solution set and determining the design set for the OFF state comprises said processor determining the design set for the OFF state as being a solution set of the P solution sets having the highest computed performance count. ### Claim 15 (depends on 14) The method of claim 14, wherein the semiconductor structure comprises a passivation layer on both the grating structure and portions of the semiconductor layer and comprising an electrically insulating material and having an index of refraction n1, wherein the semiconductor layer further comprises a plurality of doped semiconductor regions in an alternating sequence in which each channel region is disposed between a N+ doped semiconductor region of the plurality of doped semiconductor regions and a P+ doped semiconductor region of the plurality of doped semiconductor regions, wherein each channel region comprises a semiconductor material, wherein the method further comprises constraining each solution set of the P solution sets to satisfy p1=λ/(n2 sin θp1−n1 sin θi), wherein θp1 is a propagation angle for a propagation component of the light in the X direction inside the semiconductor layer, and wherein n2 is an index of refraction of the semiconductor layer. ### Claim 16 (depends on 13) The method of claim 13, wherein θi is within a range defined by θi,min≦θi≦θi,max, wherein V is within a range defined by Vmin≦V≦Vmax, and wherein said receiving input further comprises receiving a value of θi,min, θi,max, Vmin, and Vmax. ### Claim 17 (depends on 13) The method of claim 13, wherein said receiving input comprises receiving a value of an absorption coefficient threshold (Ath1) and index of refraction thresholds (n1min and n1max) such that n1minn3 and n2>n1, wherein the semiconductor layer further comprises a plurality of doped semiconductor regions in an alternating sequence of channel regions in which each channel region comprises a second semiconductor material and is disposed between and in direct mechanical contact with a N+ doped semiconductor region of the plurality of doped semiconductor regions and a P+ doped semiconductor region of the plurality of doped semiconductor regions, wherein each grating structure further comprises a gate insulator disposed between and in direct mechanical contact with the notch and a corresponding channel region of the plurality of channel regions, and wherein the notch comprises a third semiconductor material. ### Claim 19 An apparatus comprising a computer program product, said computer program product comprising a computer readable memory device having a computer readable program code embodied therein, said computer readable program code containing instructions configured to be executed by a processor of a computer system to implement a method for designing an electro-optical modulator device to operate in a reflection mode in which light having a wavelength λ is incident upon a semiconductor structure comprised by the electro-optical modulator device at an incident angle (θi) with respect to a direction opposite to a Z direction, said method comprising: said processor receiving input for designing the electro-optical modulator device to operate in the reflection mode, wherein the semiconductor structure comprises a semiconductor layer having a thickness (r) in the Z direction and a plurality of grating structures on a top surface of the semiconductor layer, wherein the Z direction is perpendicular to the top surface of the semiconductor layer, wherein the semiconductor layer comprises a plurality of semiconductor channel regions, wherein the grating structures are distributed in a periodic pattern having a pitch (p1) in an X direction that is orthogonal to the Z direction, wherein each grating structure comprises a notch and is above a corresponding channel region of the plurality of semiconductor channel regions and has a height (hg) in the Z direction above the top surface of the semiconductor layer, wherein each notch comprises a width (w1) in the X direction, wherein a voltage V applied between each notch and a corresponding doped semiconductor region in the semiconductor layer induces a change Δa of an absorption coefficient and a change Δn of an index of refraction of a semiconductor domain comprising each notch and its corresponding channel region to generate a changed absorption coefficient (a), a changed index of refraction (n), and a change in an optical path length (ΔOPL) of the semiconductor domain, wherein ΔOPL=(2π/λ)*Δn*δr, wherein δr is a total physical path length of the semiconductor domain traversed by the light incident upon the semiconductor structure at the angle θi, and wherein said receiving input comprises receiving a value of λ, r, hg, an absorption coefficient threshold (Ath0), index of refraction thresholds (n0min and n0max) such that n0min