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公开(公告)号：US11340400B2
公开(公告)日：2022-05-24
申请号：US16809640
申请日：2020-03-05
Applicant: Massachusetts Institute of Technology
Inventor： Boris Kharas , Reuel B. Swint , Cheryl Marie Sorace-Agaskar , Paul William Juodawlkis , Suraj Deepak Bramhavar , Jason Plant
Abstract: Photonic integrated circuits (PICs) enable manipulation of light on a chip for telecommunications and information processing. They can be made with silicon and silicon-compatible materials using complementary metal-oxide-semiconductor (CMOS) fabrication techniques developed for making electronics. Unfortunately, most light sources are made with III-V and II-VI materials, which are not compatible with silicon CMOS fabrication techniques. As a result, the light source for a PIC is either off-chip or integrated onto the PIC after CMOS fabrication is over. Hybrid integration can be improved by forming a recess in the PIC to receive a III-V or II-VI photonic chip. Mechanical stops formed in or next to the recess during fabrication align the photonic chip vertically to the PIC. Fiducials on the PIC and the photonic chip enable sub-micron lateral alignment. As a result, the photonic chip can be flip-chip bonded to the PIC with sub-micron vertical and lateral alignment precision.
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公开(公告)号：US11163116B2
公开(公告)日：2021-11-02
申请号：US16804612
申请日：2020-02-28
Applicant: Massachusetts Institute of Technology
Inventor： Josue Lopez , Samuel Kim , Jamison Sloan , Boris Kharas , Jeffrey Scott Herd , Marin Soljacic , Cheryl Marie Sorace-Agaskar , Suraj Deepak Bramhavar , Steven Glenn Johnson , George Barbastathis
Abstract: An integrated optical beam steering device includes a planar Luneburg lens that collimates beams from different inputs in different directions within the lens plane. It also includes a curved (e.g., semi-circular or arced) grating coupler that diffracts the collimated beams out of the lens plane. The beams can be steered in the plane by controlling the direction along which the lens is illuminated and out of the plane by varying the beam wavelength. Unlike other beam steering devices, this device can operate over an extremely wide field of view—up to 180°—without any aberrations off boresight. In other words, the beam quality is uniform in all directions, unlike with aplanatic lenses, thanks to the circular symmetry of the planar Luneburg lens, which may be composed of subwavelength features. The lens is also robust to misalignment and fabrication imperfections and can be made using standard CMOS processes.
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公开(公告)号：US20180128850A1
公开(公告)日：2018-05-10
申请号：US15807531
申请日：2017-11-08
Applicant: Massachusetts Institute of Technology
Inventor： Suraj Deepak Bramhavar , Paul William Juodawlkis
IPC: G01P15/093 , G01P15/097 , G01P15/03
CPC classification number: G01P15/093 , G01P15/032 , G01P15/097 , G01P21/00
Abstract: An accelerometer may comprise a proof mass, a first tether mechanically coupled to the side of the proof mass and to an anchor, and a ring resonator integrated with the tether to form a sensing tether. The ring resonator and the tether may be configured such that a strain sustained by the sensing tether causes a change of a resonance condition of the ring resonator. The accelerometer may comprise a wavelength locking loop configured to adaptively maintain a center frequency of the light energy at a resonant frequency of the sensing element, and a scale factor calibrator configured to stabilize a scale factor associated with the accelerometer. The accelerometer may further include a detection processor configured to receive the detection signal and produce an acceleration signal therefrom. The acceleration signal may correspond to an amount of change of the resonance condition with respect to a reference resonance condition.
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Patent Agency Ranking
公开(公告)号：US11552595B2
公开(公告)日：2023-01-10
申请号：US17007649
申请日：2020-08-31
Applicant: Massachusetts Institute of Technology
Inventor： Jeffrey Chou , Suraj Deepak Bramhavar , Christopher Roberts , Christopher A. D. Roeser , Siddhartha Ghosh
Abstract: Networks of superharmonic injection-locked (SHIL) electronic oscillators can be used to emulate Ising machines for solving difficult computational problems. The oscillators can be simulated or implemented in hardware (e.g., with LC oscillators) and are coupled to each other with links whose connection strengths are weighted according to the problem being solved. The oscillators' phases may be measured with respect to reference signal(s) from one or more reference oscillators, each of which emits a reference signal but does not receive input from any other oscillator. Sparsely connected networks of SHIL oscillators and reference oscillators can be used as Viterbi decoders that do not suffer from the information bottleneck between logic computational blocks and memory in digital computing systems. Sparsely connected networks of SHIL oscillators and reference oscillators can also be programmed to act as Boolean logic gates that operate in both forward and backward directions, enabling multipliers that can factor numbers.
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公开(公告)号：US10571483B2
公开(公告)日：2020-02-25
申请号：US15807531
申请日：2017-11-08
Applicant: Massachusetts Institute of Technology
Inventor： Suraj Deepak Bramhavar , Paul William Juodawlkis
IPC: G01P15/093 , G01P15/03 , G01P15/097 , G01P21/00
Abstract: An accelerometer may comprise a proof mass, a first tether mechanically coupled to the side of the proof mass and to an anchor, and a ring resonator integrated with the tether to form a sensing tether. The ring resonator and the tether may be configured such that a strain sustained by the sensing tether causes a change of a resonance condition of the ring resonator. The accelerometer may comprise a wavelength locking loop configured to adaptively maintain a center frequency of the light energy at a resonant frequency of the sensing element, and a scale factor calibrator configured to stabilize a scale factor associated with the accelerometer. The accelerometer may further include a detection processor configured to receive the detection signal and produce an acceleration signal therefrom. The acceleration signal may correspond to an amount of change of the resonance condition with respect to a reference resonance condition.
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公开(公告)号：US11698945B2
公开(公告)日：2023-07-11
申请号：US16832056
申请日：2020-03-27
Applicant: Massachusetts Institute of Technology
Inventor： Jeffrey Chou , Suraj Deepak Bramhavar , Siddhartha Ghosh , William Herzog
Abstract: An analog computing system with coupled non-linear oscillators can solve complex combinatorial optimization problems using the weighted Ising model. The system is composed of a fully-connected LC oscillator network with low-cost electronic components and compatible with traditional integrated circuit technologies. Each LC oscillator, or node, in the network can be coupled to each other node in the array with a multiply and accumulate crossbar array or optical interconnects. When implemented with four nodes, the system performs with single-run ground state accuracies of 98% on randomized MAX-CUT problem sets with binary weights and 84% with five-bit weight resolutions. The four-node system can obtain solutions within five oscillator cycles with a time-to-solution that scales directly with oscillator frequency. A scaling analysis suggests that larger coupled oscillator networks may be used to solve computationally intensive problems faster and more efficiently than conventional algorithms.
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公开(公告)号：US11579363B2
公开(公告)日：2023-02-14
申请号：US17496817
申请日：2021-10-08
Applicant: Massachusetts Institute of Technology
Inventor： Josue Lopez , Samuel Kim , Jamison Sloan , Boris Kharas , Jeffrey Scott Herd , Marin Soljacic , Cheryl Marie Sorace-Agaskar , Suraj Deepak Bramhavar , Steven Glenn Johnson , George Barbastathis
Abstract: An integrated optical beam steering device includes a planar Luneburg lens that collimates beams from different inputs in different directions within the lens plane. It also includes a curved (e.g., semi-circular or arced) grating coupler that diffracts the collimated beams out of the lens plane. The beams can be steered in the plane by controlling the direction along which the lens is illuminated and out of the plane by varying the beam wavelength. Unlike other beam steering devices, this device can operate over an extremely wide field of view—up to 180°—without any aberrations off boresight. In other words, the beam quality is uniform in all directions, unlike with aplanatic lenses, thanks to the circular symmetry of the planar Luneburg lens, which may be composed of subwavelength features. The lens is also robust to misalignment and fabrication imperfections and can be made using standard CMOS processes.
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公开(公告)号：US11493530B2
公开(公告)日：2022-11-08
申请号：US16677842
申请日：2019-11-08
Applicant: Massachusetts Institute of Technology
Inventor： Suraj Deepak Bramhavar , Paul William Juodawlkis
IPC: G01P15/097 , H03H3/007 , G01P15/093 , H03H9/24 , H03H9/02
Abstract: The accelerometers disclosed herein provide excellent sensitivity, long-term stability, and low SWaP-C through a combination of photonic integrated circuit technology with standard micro-electromechanical systems (MEMS) technology. Examples of these accelerometers use optical transduction to improve the scale factor of traditional MEMS resonant accelerometers by accurately measuring the resonant frequencies of very small (e.g., about 1 μm) tethers attached to a large (e.g., about 1 mm) proof mass. Some examples use ring resonators to measure the tether frequencies and some other examples use linear resonators to measure the tether frequencies. Potential commercial applications span a wide range from seismic measurement systems to automotive stability controls to inertial guidance to any other application where chip-scale accelerometers are currently deployed.
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