Patents by Inventor Radhakrishnan L. Nagarajan
Radhakrishnan L. Nagarajan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20220263289Abstract: A tunable laser for a transceiver includes a silicon photonics substrate, first and second patterned regions each being defined in the substrate a step lower than a flat surface region of the substrate, first and second laser diode chips arranged in the first and second patterned regions, the patterned regions being configured to align the gain regions of the first and second laser diode chips with integrated couplers formed in the substrate adjacent to the first and second patterned regions to facilitate flip-bonding the first and second laser diode chips within the patterned regions, and a tuning filter coupled to the first laser diode chip and the second laser diode chip via the integrated couplers. The tuning filter is configured to receive laser light from each of the first and second laser diode chips and generate a laser output having a gain determined by each of the gain regions.Type: ApplicationFiled: May 9, 2022Publication date: August 18, 2022Inventors: Radhakrishnan L. NAGARAJAN, Masaki Kato, Nourhan Eid, Kenneth Ling Wong
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Publication number: 20220255295Abstract: A high-power tunable laser includes a gain medium configured to emit light and amplify light intensity. The gain medium has a length equal to or greater than 1.5 mm between a backend and a frontend configured to be an output port for outputting light with amplified intensity. The high-power tunable laser further includes a wavelength tuner optically coupled to the backend to receive light from the gain medium and configured to tune wavelength for the light and have a high-reflectivity reflector to reflect the light with a tuned wavelength back to the gain medium.Type: ApplicationFiled: February 5, 2021Publication date: August 11, 2022Inventors: Xiaoguang HE, Radhakrishnan L. NAGARAJAN
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Patent number: 11394464Abstract: An coherent transceiver includes a single silicon photonics substrate configured to integrate a laser diode chip flip-mounted and coupled with a wavelength tuning section to provide a laser output with tuned wavelengths which is split in X:Y ratio partly into a coherent receiver block as local-oscillator signals and partly into a coherent transmitter block as a light source. The coherent receiver includes a polarization-beam-splitter-rotator to split a coherent input signal to a TE-mode signal and a TM*-mode signal respectively detected by two 90-deg hybrid receivers and a flip-mounted TIA chip assisted by two local-oscillator signals from the tunable laser device.Type: GrantFiled: July 14, 2020Date of Patent: July 19, 2022Assignee: Marvell Asia Pte Ltd.Inventor: Radhakrishnan L. Nagarajan
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Patent number: 11392534Abstract: The present invention provides an optical module for communicating a peer to peer transaction to transmit cryptocurrency. The optical module includes a substrate, a memory resource formed on the substrate, and a cryptocurrency wallet provided on the memory resource. Additionally, the optical module includes an optical communication block configured to generate an optical signal based on an electrical signal carrying a transaction message about an order of executing a plurality of transactions of cryptocurrency. The optical module includes an internal encryption block for encrypting the optical signal in the quadrature phases using an optical Quantum Key Generation encryption protocol.Type: GrantFiled: June 25, 2020Date of Patent: July 19, 2022Assignee: Marvell Asia Pte Ltd.Inventor: Radhakrishnan L. Nagarajan
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Publication number: 20220221668Abstract: An apparatus for dissipating heat from a photonic transceiver module. The apparatus includes a top-plate member disposed in a length direction of a package for the photonic transceiver module. The apparatus further includes multiple fins formed on the top-plate member along the length direction from a backend position to a frontend position except at least one fin with a shorter length, forming an elongated void from the backend position to one backend of the at least one fin. Additionally, the apparatus includes a cover member disposed over the multiple fins with a horizontal sheet, two vertical side sheets, and a flange bent vertically from a middle portion of backend of the horizontal sheet. Furthermore, the apparatus includes a spring loaded in the elongated void between the flange and the one backend of the at least one fin to minimize an air gap at the backend of the horizontal sheet.Type: ApplicationFiled: March 28, 2022Publication date: July 14, 2022Inventors: Chris TOGAMI, Radhakrishnan L. NAGARAJAN, Gary SASSER, Brian TAYLOR
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Patent number: 11388268Abstract: A first processing unit for a computer server apparatus includes a first circuit configured to process a first type of data to be transmitted and received over a communication channel in accordance with a peripheral component interconnect express (PCIe) protocol, a second circuit configured to process a second type of data to be transmitted and received over the communication channel in accordance with a compute express link (CXL) protocol, and an optical communication interface configured to modulate the first type of data and the second type of data into a first signal in a PAM format to be transmitted over the communication channel to a second processing unit and receive, from the second processing unit over the communication channel, a second signal including either one of the first type of data and the second type of data modulated in the PAM format.Type: GrantFiled: January 30, 2020Date of Patent: July 12, 2022Assignee: Marvell Asia Pte Ltd.Inventors: Kumaran David Siva, Arash Farhoodfar, Radhakrishnan L. Nagarajan
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Patent number: 11381313Abstract: An integrated optical transceiver includes a transmitter unit and a receiver unit each provided on a surface region of a substrate member. The transmitter unit includes four laser devices configured to output four laser lights and a set of four power splitter devices coupled to the four laser lights to split each of the four laser lights to two replicated transmit paths. The receiver unit has two replicated receive paths each including a photodetector device and a transimpedance amplifier device coupled to the photodetector device. A planar light circuit block is mounted on the substrate member and includes a multiplexer device configured to couple the four laser lights of the transmitter unit and multiplex to one output light delivered to an optical output port and a demultiplexer device configured to receive an input light from an optical input port and demultiplex to four input optical signals for the receiver unit.Type: GrantFiled: December 9, 2020Date of Patent: July 5, 2022Assignee: MARVELL ASIA PTE LTD.Inventors: Ding Liang, Mark Patterson, Roberto Coccioli, Radhakrishnan L. Nagarajan
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Patent number: 11367687Abstract: A method for forming a silicon photonics interposer having through-silicon vias (TSVs). The method includes forming vias in a front side of a silicon substrate and defining primary structures for forming optical devices in the front side. Additionally, the method includes bonding a first handle wafer to the front side and thinning down the silicon substrate from the back side and forming bumps at the back side to couple with a conductive material in the vias. Furthermore, the method includes bonding a second handle wafer to the back side and debonding the first handle wafer from the front side to form secondary structures based on the primary structures. Moreover, the method includes forming pads at the front side to couple with the bumps at the back side before completing final structures based on the secondary structures and debonding the second handle wafer from the back side.Type: GrantFiled: January 9, 2020Date of Patent: June 21, 2022Assignee: MARVELL ASIA PTE LTD.Inventors: Liang Ding, Radhakrishnan L. Nagarajan
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Publication number: 20220190560Abstract: A gain medium for semiconductor optical amplifier in high-power operation includes a substrate with n-type doping; a lower clad layer formed overlying the substrate; a lower optical confinement stack overlying the lower clad layer; an active layer comprising a multi-quantum-well heterostructure with multiple well layers characterized by about 0.8% to 1.2% compressive strain respectively separated by multiple barrier layers characterized by about ?0.1% to ?0.5% tensile strain. The active layer overlays the lower optical confinement stack. The gain medium further includes an upper optical confinement stack overlying the active layer, the upper optical confinement stack being set thinner than the lower optical confinement stack; an upper clad layer overlying the upper optical confinement stack; and a p-type contact layer overlying the upper clad layer.Type: ApplicationFiled: December 15, 2020Publication date: June 16, 2022Inventors: Xiaoguang HE, Radhakrishnan L. NAGARAJAN
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Patent number: 11355900Abstract: A packaged transmitter device includes a base member comprising a planar part mounted with a thermoelectric cooler, a transmitter, and a coupling lens assembly, and an assembling part connected to one side of the planar part. The device further includes a circuit board bended to have a first end region and a second end region being raised to a higher level. The first end region disposed on a top surface of the planar part includes multiple electrical connection patches respectively connected to the thermoelectric and the transmitter. The second end region includes an electrical port for external connection. Additionally, the device includes a cover member disposed over the planar part. Furthermore, the device includes a cylindrical member installed to the assembling part for enclosing an isolator aligned to the coupling lens assembly along its axis and connected to a fiber to couple optical signal from the transmitter to the fiber.Type: GrantFiled: December 8, 2020Date of Patent: June 7, 2022Assignee: MARVELL ASIA PTE LTD.Inventors: Radhakrishnan L. Nagarajan, Peng-Chih Li, Pi-Cheng Law
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Patent number: 11341083Abstract: The present invention includes an integrated system-on-chip device configured on a substrate member. The device has a data input/output interface provided on the substrate member and configured for a predefined data rate and protocol. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The input/output block comprises a SerDes block, a CDR block, a compensation block, and an equalizer block. The SerDes block is configured to convert a first data stream of N having a first predefined data rate at a first clock rate into a second data stream of M having a second predefined data rate at a second clock rate. The device has a driver module provided on the substrate member and coupled to a signal processing block, and a driver interface provided on the substrate member and coupled to the driver module and a silicon photonics device.Type: GrantFiled: November 3, 2020Date of Patent: May 24, 2022Assignee: Marvell Asia Pte Ltd.Inventors: Radhakrishnan L. Nagarajan, Chao Xu
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Patent number: 11329452Abstract: A tunable laser device based on silicon photonics includes a substrate configured with a patterned region comprising one or more vertical stoppers, an edge stopper facing a first direction, a first alignment feature structure formed in the patterned region along the first direction, and a bond pad disposed between the vertical stoppers. Additionally, the tunable laser includes an integrated coupler built in the substrate located at the edge stopper and a laser diode chip including a gain region covered by a P-type electrode and a second alignment feature structure formed beyond the P-type electrode. The laser diode chip is flipped to rest against the one or more vertical stoppers with the P-type electrode attached to the bond pad and the gain region coupled to the integrated coupler. Moreover, the tunable laser includes a tuning filter fabricated in the substrate and coupled via a wire waveguide to the integrated coupler.Type: GrantFiled: March 13, 2020Date of Patent: May 10, 2022Assignee: Marvell Asia Pte Ltd.Inventors: Radhakrishnan L. Nagarajan, Masaki Kato, Nourhan Eid, Kenneth Ling Wong
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Publication number: 20220140899Abstract: The present invention is directed to communication systems and methods. According to an embodiment, a receiving optical transceiver determines signal quality for signals received from a transmitting optical transceiver. Information related to the signal quality is embedded into back-channel data and sent to the transmitting optical transceiver. The transmitting optical transceiver detects the presence of the back-channel data and adjusts one or more of its operating parameters based on the back-channel data. There are other embodiments as well.Type: ApplicationFiled: January 14, 2022Publication date: May 5, 2022Inventors: Todd ROPE, Radhakrishnan L. NAGARAJAN
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Publication number: 20220123852Abstract: An in-packaged multi-channel light engine is packaged for four or more sub-assemblies of optical-electrical sub-modules. Each is assembled with at least four laser chips, one or more driver chip, and one or more trans-impedance amplifier (TIA) chip separately flip-mounted on a silicon photonics interposer and is coupled to an optical interface block and an electrical interface block on a sub-module substrate. The in-packaged multi-channel light engine further includes a first frame fixture holding the four or more sub-assemblies and a second frame fixture configured to hold the first frame fixture with the four or more sub-assemblies. The in-packaged multi-channel light engine further includes an interposer plate inserted between the sub-module substrates and a module substrate and is compressed between a backplate member attached to a bottom side of the module substrate and a top plate member configured as a heatsink with a plurality of fin structures.Type: ApplicationFiled: December 28, 2021Publication date: April 21, 2022Inventors: Radhakrishnan L. NAGARAJAN, Liang DING, Mark PATTERSON, Roberto COCCIOLI
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Publication number: 20220123518Abstract: A laser chip for flip-chip bonding on a silicon photonics chip with passive alignment features. The laser chip includes a chip body made of a p-region and a n-region in vertical direction and extended from a front facet to a rear facet in longitudinal direction, a pair of first vertical stoppers formed respectively beyond two sides of the chip body based on a wider width of the n-region, an active region buried in the chip body between the p-region and the n-region in the vertical direction and extended from the front facet to the rear facet in the longitudinal direction, an alignment mark formed on a top surface of the p-region near the front facet with a lateral distance defined in sub-micron precision relative to the active region; and a thin metal film on the surface of the p-region having a cleaved edge shared with the front facet.Type: ApplicationFiled: October 21, 2020Publication date: April 21, 2022Inventors: Xiaoguang He, Radhakrishnan L. Nagarajan
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Patent number: 11287586Abstract: An apparatus for dissipating heat from a photonic transceiver module. The apparatus includes a top-plate member disposed in a length direction of a package for the photonic transceiver module. The apparatus further includes multiple fins formed on the top-plate member along the length direction from a backend position to a frontend position except at least one fin with a shorter length, forming an elongated void from the backend position to one backend of the at least one fin. Additionally, the apparatus includes a cover member disposed over the multiple fins with a horizontal sheet, two vertical side sheets, and a flange bent vertically from a middle portion of backend of the horizontal sheet. Furthermore, the apparatus includes a spring loaded in the elongated void between the flange and the one backend of the at least one fin to minimize an air gap at the backend of the horizontal sheet.Type: GrantFiled: November 11, 2020Date of Patent: March 29, 2022Assignee: Marvell Asia Pte Ltd.Inventors: Chris Togami, Radhakrishnan L. Nagarajan, Gary Sasser, Brian Taylor
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Publication number: 20220085575Abstract: A semiconductor optical amplifier for high-power operation includes a gain medium having a multilayer structure sequentially laid with a P-layer, an active layer, a N-layer from an upper portion to a lower portion in cross-section thereof. The gain medium is extendedly laid with a length L from a front facet to a back facet. The active layer includes multiple well layers formed by undoped semiconductor material and multiple barrier layers formed by n-doped semiconductor materials. Each well layer is sandwiched by a pair of barrier layers. The front facet is characterized by a first reflectance Rf and the back facet is characterized by a second reflectance Rb. The gain medium has a mirror loss ?m about 40-200 cm?1 given by: ?m=(½L)ln{1/(Rf×Rb)}.Type: ApplicationFiled: September 17, 2020Publication date: March 17, 2022Applicant: Inphi CorporationInventors: Xiaoguang HE, Radhakrishnan L. NAGARAJAN
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Patent number: 11238428Abstract: The present invention is directed to an optical module based on silicon photonics. The optical module provides a cyptocurrency wallet stored in a memory resource and includes an optical communication block with a direct-to-cloud interface for connecting to entities in a cloud infrastructure. The optical module further includes an application block to enable a cryptocurrency transaction via the direct-to-cloud interface. The optical module is configured to be an optical Quantum Key Generation Distribution device using a quantum key generation encryption protocol to encrypt a private key protected transaction in an encrypted transaction envelope. Furthermore, the optical module includes an external interface connecting the application block to a user/host via a physical layer to establish a secure link before executing a peer-to-peer transaction between entities in the cloud infrastructure.Type: GrantFiled: April 25, 2018Date of Patent: February 1, 2022Assignee: Marvell Asia Pte, Ltd.Inventor: Radhakrishnan L. Nagarajan
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Patent number: 11239912Abstract: The present invention is directed to communication systems and methods. According to an embodiment, a receiving optical transceiver determines signal quality for signals received from a transmitting optical transceiver. Information related to the signal quality is embedded into back-channel data and sent to the transmitting optical transceiver. The transmitting optical transceiver detects the presence of the back-channel data and adjusts one or more of its operating parameters based on the back-channel data. There are other embodiments as well.Type: GrantFiled: October 15, 2020Date of Patent: February 1, 2022Assignee: MARVELL ASIA PTE LTD.Inventors: Todd Rope, Radhakrishnan L. Nagarajan
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Publication number: 20220013978Abstract: A method for improving wide-band wavelength-tunable laser. The method includes configuring a gain region between a first facet and a second facet and crosswise a PN-junction with an active layer between P-type cladding layer and N-type cladding layer. The method further includes coupling a light excited in the active layer and partially reflected from the second facet to pass through the first facet to a wavelength tuner configured to generate a joint interference spectrum with multiple modes separated by a joint-free-spectral-range (JFSR). Additionally, the method includes configuring the second facet to have reduced reflectivity for increasing wavelengths. Furthermore, the method includes reconfiguring the gain chip with an absorption layer near the active layer to induce a gain loss for wavelengths shorter than a longest wavelength associated with a short-wavelength side mode. Moreover, the method includes outputting amplified light at a basic mode via the second facet.Type: ApplicationFiled: July 7, 2020Publication date: January 13, 2022Inventors: Xiaoguang HE, Radhakrishnan L. NAGARAJAN