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11.发明公开公开(公告)号：US20230208628A1
公开(公告)日：2023-06-29
申请号：US18146085
申请日：2022-12-23
Applicant: Massachusetts Institute of Technology
Inventor： Stefan Ivanov Krastanov , Hamza Raniwala , Hanfeng WANG , Matthew Edwin TRUSHEIM , Laura KIM , Dirk Robert ENGLUND
CPC classification number: H04L9/0855 , H04B10/70
Abstract: A 1D diamond nanobeam can act as a coherent mechanical interface between spin defect centers in diamond and telecom optical modes. The nanobeam includes embedded mechanical and electric field concentrators with mechanical and optical mode volumes of Vmech/Λp3 ˜10−5 and Vopt/λ3 ˜10−3, respectively. With a Group IV vacancy in the concentrator, the nanobeam can operate at spin-mechanical coupling rates approaching 40 MHz with high acousto-optical couplings. This nanobeam, used in an entanglement heralding scheme, can provide high-fidelity Bell pairs between quantum repeaters. Using the mechanical interface as an intermediary between the optical and spin subsystems enables addressing the spin defect center with telecom optics, bypassing the native wavelength of the spin. As the spin is never optically excited or addressed, the device can operate at temperatures up to 40 K with no appreciable spectral diffusion, limited by thermal losses. Optomechanical devices with high spin-mechanical coupling can be useful for quantum repeaters.
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公开(公告)号：US20210240016A1
公开(公告)日：2021-08-05
申请号：US17216272
申请日：2021-03-29
Applicant: Massachusetts Institute of Technology
Inventor： Christopher Louis Panuski , Dirk Robert ENGLUND
IPC: G02F1/025
Abstract: A spatial light modulator (SLM) comprised of a 2D array of optically-controlled semiconductor nanocavities can have a fast modulation rate, small pixel pitch, low pixel tuning energy, and millions of pixels. Incoherent pump light from a control projector tunes each PhC cavity via the free-carrier dispersion effect, thereby modulating the coherent probe field emitted from the cavity array. The use of high-Q/V semiconductor cavities enables energy-efficient all-optical control and eliminates the need for individual tuning elements, which degrade the performance and limit the size of the optical surface. Using this technique, an SLM with 106 pixels, micron-order pixel pitch, and GHz-order refresh rates could be realized with less than 1 W of pump power.
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公开(公告)号：US20180335574A1
公开(公告)日：2018-11-22
申请号：US15982035
申请日：2018-05-17
Applicant: Massachusetts Institute of Technology
Inventor： Gregory R. STEINBRECHER , Dirk Robert ENGLUND
Abstract: A method of nonblocking optical switching includes guiding a first optical beam from a first input to a first output via a first path through an optical switching fabric. The first path traverses a phase shifter disposed between a pair of cascaded Mach-Zehnder interferometers. The method also includes receiving a second optical beam for a second path intersecting with the first path through the optical switching fabric. The method also includes moving the first optical beam from the first path to a third path connecting the first input to the first output without intersecting the second path. The method also includes shifting a phase of the first optical beam, with the phase shifter, while moving the first optical beam from the first path to the third path to prevent the first optical beam from interfering with the second optical beam.
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公开(公告)号：US20250085100A1
公开(公告)日：2025-03-13
申请号：US18956238
申请日：2024-11-22
Inventor： Ryan HAMERLY , Saumil Bandyopadhyay , Dirk Robert ENGLUND
IPC: G01B9/02055 , G01B9/02001
Abstract: Component errors prevent linear photonic circuits from being scaled to large sizes. These errors can be compensated by programming the components in an order corresponding to nulling operations on a target matrix X through Givens rotations X→T†X, X→XT†. Nulling is implemented on hardware through measurements with feedback, in a way that builds up the target matrix even in the presence of hardware errors. This programming works with unknown errors and without internal sources or detectors in the circuit. Modifying the photonic circuit architecture can reduce the effect of errors still further, in some cases even rendering the hardware asymptotically perfect in the large-size limit. These modifications include adding a third directional coupler or crossing after each Mach-Zehnder interferometer in the circuit and a photonic implementation of the generalized FFT fractal. The configured photonic circuit can be used for machine learning, quantum photonics, prototyping, optical switching/multicast networks, microwave photonics, or signal processing.
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15.发明公开公开(公告)号：US20240078462A1
公开(公告)日：2024-03-07
申请号：US18493257
申请日：2023-10-24
Applicant: Massachusetts Institute of Technology
Inventor： Hyeongrak CHOI , Dirk Robert ENGLUND
Abstract: Quantum information processing involves entangling large numbers of qubits, which can be realized as defect centers in a solid-state host. The qubits can be implemented as individual unit cells, each with its own control electronics, that are arrayed in a cryostat. Free-space control and pump beams address the qubit unit cells through a cryostat window. The qubit unit cells emit light in response to these control and pump beams and microwave pulses applied by the control electronics. The emitted light propagates through free space to a mode mixer, which interferes the optical modes from adjacent qubit unit cells for heralded Bell measurements. The qubit unit cells are small (e.g., 10 μm square), so they can be tiled in arrays of up to millions, addressed by free-space optics with micron-scale spot sizes. The processing overhead for this architecture remains relatively constant, even with large numbers of qubits, enabling scalable large-scale quantum information processing.
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Patent Agency Ranking
16.发明公开公开(公告)号：US20230344516A1
公开(公告)日：2023-10-26
申请号：US17412877
申请日：2021-08-26
Applicant: Massachusetts Institute of Technology
Inventor： Eric Alexander Bersin , Carlos Errando Herranz , Dirk Robert ENGLUND
CPC classification number: H04B10/29 , G02F1/353 , G02F1/3551 , H04B10/70
Abstract: A spectrally multiplexed quantum repeater (SMuQR) based on spatially arrayed nodes of frequency-multiplexed multi-qubit registers uses the natural inhomogeneous distribution of optical transition frequencies in solid state defect centers. This distribution enables spectrally selective, individual addressing of large numbers of defect centers within an optical diffraction limited spot along a long cavity or waveguide. The spectral selection relies on frequency shifting an incident optical field at a rate as fast as once per defect center lifetime. The defect centers are resonant at visible frequencies and emit visible single photons which are down-converted to a wavelength compatible with long-distance transmission via conventional optical fiber. The down-converted photons are all at the same telecommunications wavelength, with the different spectral bins mapped to different temporal bins to preserve the multiplexing in the time domain, for distribution to other nodes in the quantum network.
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公开(公告)号：US20230342650A1
公开(公告)日：2023-10-26
申请号：US18172431
申请日：2023-02-22
Applicant: Massachusetts Institute of Technology
Inventor： Kevin Chen , Prajit Dhara , Saikat Guha , Dirk Robert ENGLUND
Abstract: We disclose optical entanglement distribution in quantum networks based on a quasi-deterministic entangled photon pair source. Combining heralded photonic Bell pair generation with spectral mode conversion to interface with quantum memories eliminates switching losses due to multiplexing in the source. This zero-added-loss multiplexing (ZALM) Bell pair source is especially useful for the particularly challenging problem of long-baseline entanglement distribution via satellites and ground-based memories, where it unlocks additional advantages: (i) the substantially higher channel efficiency η of downlinks versus uplinks with realistic adaptive optics, and (ii) photon loss occurring before interaction with the quantum memory—i.e., Alice and Bob receiving rather than transmitting—improve entanglement generation rate scaling by (√{square root over (η)}). Numerical analyses suggest that this protocol can achieve >10 ebit/s at memory multiplexing of 102 spin qubits for ground distance >102 km, with the spin-spin Bell state fidelity exceeding 99%.
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18.发明公开公开(公告)号：US20230281437A1
公开(公告)日：2023-09-07
申请号：US18149249
申请日：2023-01-03
Applicant: Massachusetts Institute of Technology
Inventor： Ronald A. Davis , Dirk Robert ENGLUND
CPC classification number: G06N3/0675 , G06N3/065
Abstract: A multiplicative analog frequency transform optical neural network (MAFT-ONN) encodes data in the frequency domain, achieves matrix-vector products in a single shot using photoelectric multiplication, and uses a single electro-optic modulator for the nonlinear activation of all neurons in each layer. Photoelectric multiplication between radio frequency (RF)-encoded optical frequency combs allows single-shot matrix-vector multiplication and nonlinear activation, leading to high throughput and ultra-low latency. This frequency-encoding scheme can be implemented with several neurons per hardware spatial mode and allows for an arbitrary number of layers to be cascaded in the analog domain. For example, a three-layer DNN can compute over four million fully analog operations and implement both a convolutional and fully connected layer. Additionally, a MAFT-ONN can perform analog DNN inference of temporal waveforms like voice or radio signals, achieving bandwidth-limited throughput, speed of light-limited latency, and fully analog complex-valued matrix operations.
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公开(公告)号：US20220236113A1
公开(公告)日：2022-07-28
申请号：US17335017
申请日：2021-05-31
Applicant: Massachusetts Institute of Technology
Inventor： Jordan Goldstein , Christopher Louis Panuski , Dirk Robert ENGLUND
Abstract: Optical microcavity resonance measurements can have readout noise matching the fundamental limit set by thermal fluctuations in the cavity. Small-heat-capacity, wavelength-scale microcavities can be used as bolometers that bypass the limitations of other bolometer technologies. The microcavities can be implemented as photonic crystal cavities or micro-disks that are thermally coupled to strong mid-IR or LWIR absorbers, such as pyrolytic carbon columns. Each microcavity and the associated absorber(s) rest on hollow pillars that extend from a substrate and thermally isolate the cavity and the absorber(s) from the rest of the bolometer. This ensures that thermal transfer to the absorbers is predominantly from radiation as opposed to from conduction. As the absorbers absorb thermal radiation, they shift the resonance wavelength of the cavity. The cavity transduces this thermal change into an optical signal by reflecting or scattering more (or less) near-infrared (NIR) probe light as a function of the resonance wavelength shift.
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公开(公告)号：US20220137169A1
公开(公告)日：2022-05-05
申请号：US17465895
申请日：2021-09-03
Applicant: Massachusetts Institute of Technology
Inventor： Dirk Robert ENGLUND
Abstract: Chemical-shift nuclear magnetic resonance (NMR) spectroscopy involves measuring the effects of chemical bonds in a sample on the resonance frequencies of nuclear spins in the sample. Applying a magnetic field to the sample causes the sample nuclei to emit alternating current magnetic fields that can be detected with color centers, which can act as very sensitive magnetometers. Cryogenically cooling the sample increases the sample's polarization, which in turn enhances the NMR signal strength, making it possible to detect net nuclear spins for very small samples. Flash-heating the sample or subjecting it to a magic-angle-spinning magnetic field (instead of a static magnetic field) eliminates built-in magnetic field inhomogeneities, improving measurement sensitivity without degrading the sample polarization. Tens to hundreds of small, cryogenically cooled sample chambers can be integrated in a semiconductor substrate interlaced with waveguides that contain color centers for optically detected magnetic resonance measurements of the samples' chemical-shift NMR frequencies.
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