Thermal dissipation enhancement in flip-chip bonded uni-traveling carrier photodiodes.

The thermal properties of modified uni-traveling carrier (MUTC) photodiode flip-chip bonded to AlN and diamond are simulated. The thermal impedance of InGaAs is the primary source of internal heating. An n-down epitaxial structure is designed to improve thermal dissipation.

ChanFAD: A Functional Annotation Database for Ion Channels.

Ion channels are integral membrane protein complexes critical for regulation of membrane potential, cell volume, and other signaling events. As complex molecular assemblies with many interacting partners, ion channels have multiple structural and functional domains. While channel sequence and functional data are readily available across multiple online resources, there is an unmet need for functional annotation directly relating primary sequence information, 2D interactions, and three-dimensional protein structure.

Bioindustrial manufacturing readiness levels (BioMRLs) as a shared framework for measuring and communicating the maturity of bioproduct manufacturing processes.

Readiness level (RL) frameworks such as technology readiness levels and manufacturing readiness levels describe the status of a technology/manufacturing process on its journey from initial conception to commercial deployment. More importantly, they provide a roadmap to guide technology development and scale-up from a ''totality of system'' approach. Commercialization risks associated with too narrowly focused R&D efforts are mitigated.

Compact thin film lithium niobate folded intensity modulator using a waveguide crossing.

A small footprint, low voltage and wide bandwidth electro-optic modulator is critical for applications ranging from optical communications to analog photonic links, and the integration of thin-film lithium niobate with photonic integrated circuit (PIC) compatible materials remains paramount. Here, a hybrid silicon nitride and lithium niobate folded electro-optic Mach Zehnder modulator (MZM) which incorporates a waveguide crossing and 3 dB multimode interference (MMI) couplers for splitting and combining light is reported. This modulator has an effective interaction region length of 10 mm and shows a DC half wave voltage of roughly 4.

Instantaneous microwave-photonic spatial-spectral channelization via k-space imaging.

The ability to both spatially and spectrally demultiplex wireless transmitters enables communication networks with higher spectral and energy efficiency. In practice, demultiplexing requires sub-millisecond latency to map the dynamics of the user space in real-time. Here, we present a system architecture, referred to as k-space imaging, which channelizes the radio frequency signals both spatially and spectrally through optical beamforming, where the latency is limited only by the speed of light traversing the optical components of the receiver.

Log-periodic temporal apertures for grating lobe suppression in k-space tomography.

Millimeter-wave (mmW) imaging receivers have demonstrated the ability to sense radio-frequency (RF) waves using traditional phased antenna array techniques, and, through a coherent photonic up-conversion process, image these waves using free-space optical systems. Building upon the idea of coherent up-conversion, k-space tomography extends the functionality of the millimeter-wave imaging receiver as a two-dimensional spatial processing unit to three-dimensional sensing with the addition of frequency detection. In this configuration, an arrayed waveguide grating, or temporal aperture, is implemented following the photonic up-conversion of RF signals received by the phased array.

Subvolt electro-optical modulator on thin-film lithium niobate and silicon nitride hybrid platform.

A low voltage operation electro-optic modulator is critical for applications ranging from optical communications to an analog photonic link. This paper reports a hybrid silicon nitride and lithium niobate electro-optic Mach-Zehnder modulator that employs 3 dB multimode interference couplers for splitting and combining light. The presented amplitude modulator with an interaction region length of 2.

High-performance racetrack resonator in silicon nitride - thin film lithium niobate hybrid platform.

In this paper, we propose an electro-optic modulator design in a hybrid SiN-X-cut LiNbO. The modulator is based on a modified racetrack resonator and performs at both DC and heightened frequencies. Here the driving electrodes are defined along the straight section of the racetrack.

Tunable hybrid silicon nitride and thin-film lithium niobate electro-optic microresonator.

This Letter presents, to the best of our knowledge, the first hybrid --based tunable microring resonator where the waveguide is formed by loading a strip on an electro-optic (EO) material of -cut thin-film . The developed hybrid - microring exhibits a high intrinsic quality factor of 1.85×10, with a ring propagation loss of 0.

Vertical mode transition in hybrid lithium niobate and silicon nitride-based photonic integrated circuit structures.

This Letter presents an optical mode transition structure for use in /-based hybrid photonics. A gradual modal transition from a waveguide to a hybrid / waveguide is achieved by etching a terrace structure into the sub-micrometer thick film. The etched film is then bonded to predefined low pressure chemical vapor deposition waveguides.

Insights into the Voltage Regulation Mechanism of the Pore-Forming Toxin Lysenin.

Lysenin, a pore forming toxin (PFT) extracted from , inserts voltage-regulated channels into artificial lipid membranes containing sphingomyelin. The voltage-induced gating leads to a strong static hysteresis in conductance, which endows lysenin with molecular memory capabilities. To explain this history-dependent behavior, we hypothesized a gating mechanism that implies the movement of a voltage domain sensor from an aqueous environment into the hydrophobic core of the membrane under the influence of an external electric field.

Thin film lithium niobate electro-optic modulator with terahertz operating bandwidth.

We present a thin film crystal ion sliced (CIS) LiNbO phase modulator that demonstrates an unprecedented measured electro-optic (EO) response up to 500 GHz. Shallow rib waveguides are utilized for guiding a single transverse electric (TE) optical mode, and Au coplanar waveguides (CPWs) support the modulating radio frequency (RF) mode. Precise index matching between the co-propagating RF and optical modes is responsible for the device's broadband response, which is estimated to extend even beyond 500 GHz.

Photonic probing of radio waves for k-space tomography.

We harness coherent optical processing to simultaneously sense the angle of arrival and the frequency of radio waves. Signals captured by a distributed antenna array are up-converted to optical domain using electro-optic modulators coupled to individual antennas. Employing a common laser source to feed all the modulators ensures spatially coherent up-conversion of radio-frequency (RF) waves to optical beams carried by optical fibers.

110 GHz CMOS compatible thin film LiNbO3 modulator on silicon.

In this paper we address a significant limitation of silicon as an optical material, namely, the upper bound of its potential modulation frequency. This arises due to finite carrier mobility, which fundamentally limits the frequency response of all-silicon modulators to about 60 GHz. To overcome this limitation, another material must be integrated with silicon to provide increased operational bandwidths.

Thin LiNbO3 on insulator electro-optic modulator.

This Letter presents a method for the fabrication and integration of a thin LiNbO3 substrate with a Si handle wafer. An inverted ridge structure guides a single optical mode in an electro-optic modulator fabricated on a mechanically thinned substrate. To define an optical waveguide, a ridge structure is first patterned on a 500 μm thick X-cut LiNbO3 wafer; then a low dielectric constant adhesive layer is used to bond the etched LiNbO3 to Si.

Packaging and design of a heterogeneous dual laser chip for a widely tunable spectrally pure optical RF source.

In this paper, we report the results of the efforts to extend our previous work through the packaging and redesign of a heterogeneously integrated silicon-photonic circuit for use in a modulation side-band injection-locked optical RF generation system. Towards that effort, we attempted to improve the RF spectrum coverage of our design by decreasing the laser cavity length. Despite the unintended formation of an additional parasitic cavity in that device, we demonstrated increased spectrum coverage between 5 and 50 GHz in a packaged module with an ∼ 1-Hz linewidth.

Improved configuration and reduction of phase noise in a narrow linewidth ultrawideband optical RF source.

In this Letter, we report on the improved configuration of a widely tunable optical RF generation system, particularly for the generation of low-frequency RF, as well as the reduction of phase noise in that same system. Using an amplitude modulator, a simplified system design was demonstrated with fewer components and improved phase noise performance, especially at RF frequencies below ∼36 GHz. Excess phase noise due to acoustic vibrations of the optical fibers was also successfully eliminated by mechanical isolation.

A single adiabatic microring-based laser in 220 nm silicon-on-insulator.

We demonstrate a laser for the silicon photonics platform by hybrid integration with a III/V reflective semiconductor optical amplifier coupled to a 220 nm silicon-on-insulator half-cavity. We utilize a novel ultra-thin silicon edge coupler. A single adiabatic microring based inline reflector is used to select a lasing mode, as compared to the multiple rings and Bragg gratings used in many previous results.

Measured comparison of contrast and crossover periods for passive millimeter-wave polarimetric imagery.

Several targets are set-up outside and imaged by a passive millimeter-wave sensor over a 24 hour period. The sensor is capable of measuring two linear polarization states simultaneously and the contrasts of the targets are compared for the different polarizations. The choice of polarization is shown to have an impact on the contrast of different targets throughout the day.

Demonstration of high-Q mid-infrared chalcogenide glass-on-silicon resonators.

We demonstrated high-index-contrast, waveguide-coupled As2Se3 chalcogenide glass resonators monolithically integrated on silicon fabricated using optical lithography and a lift-off process. The resonators exhibited a high intrinsic quality factor of 2×10(5) at 5.2 μm wavelength, which is among the highest values reported in on-chip mid-infrared (mid-IR) photonic devices.

Higher-order computational model for coded aperture spectral imaging.

Coded aperture snapshot spectral imaging systems (CASSI) sense the three-dimensional spatio-spectral information of a scene using a single two-dimensional focal plane array snapshot. The compressive CASSI measurements are often modeled as the summation of coded and shifted versions of the spectral voxels of the underlying scene. This coarse approximation of the analog CASSI sensing phenomena is then compensated by calibration preprocessing prior to signal reconstruction.

Full spectrum millimeter-wave modulation.

In recent years, the development of new lithium niobate electro-optic modulator designs and material processing techniques have contributed to support the increasing need for faster optical networks by considerably extending the operational bandwidth of modulators. In an effort to provide higher bandwidths for future generations of networks, we have developed a lithium niobate electro-optic phase modulator based on a coplanar waveguide ridged structure that operates up to 300 GHz. By thinning the lithium niobate substrate down to less than 39 µm, we are able to eliminate substrate modes and observe optical sidebands over the full millimeter-wave spectrum.

Dynamically induced nonlinearity in a resonant-cavity interferometric intensity modulator.

The frequency dependence of the spur-free dynamic range (SFDR) in a modulator based on an injection-locked laser is analyzed. It is shown that as the modulation frequency approaches half of the locking range, the SFDR of the modulator approaches that of a standard Mach-Zehnder configuration. At low frequencies, the SFDR degrades by 2 dB for every octave of frequency increase.

Development of a digital-micromirror-device-based multishot snapshot spectral imaging system.

We report on the development of a digital-micromirror-device (DMD)-based multishot snapshot spectral imaging (DMD-SSI) system as an alternative to current piezostage-based multishot coded aperture snapshot spectral imager (CASSI) systems. In this system, a DMD is used to implement compressive sensing (CS) measurement patterns for reconstructing the spatial/spectral information of an imaging scene. Based on the CS measurement results, we demonstrated the concurrent reconstruction of 24 spectral images.