Ellisongustafson5527

In this paper we report the design of a device allowing on-chip optical wireless interconnections, based on transmitting and receiving Optical Phased Arrays (OPA). The proposed device aims at realizing high-bandwidth and power-efficient reconfigurable connections between multiple nodes, e.g. chiplets stacked onto a common silicon interposer in 2.5D manycore systems. The communication through an optical wireless switch is a completely novel approach to overcome the bottleneck of wired communication and to provide flexibility in the network topology configuration. We report the OPA design criteria as well as the results of three-dimensional Finite Difference Time Domain (FDTD) simulations. We exploit the in-plane radiation of simple taper antennas to implement 1×N and N × N switching matrices. The effect of the multipath propagation in the on-chip multi-layered medium is also taken into account.Due to the increased surface-to-volume ratio, the surface recombination caused by sidewall defects is a key obstacle that limits the external quantum efficiency (EQE) for GaN-based micro-light-emitting diodes (µLEDs). In this work, we propose selectively removing the periphery p+-GaN layer so that the an artificially formed resistive ITO/p-GaN junction can be formed at the mesa edge. Three types of LEDs with different device dimensions of 30 × 30 µm2, 60 × 60 µm2 and 100 × 100 µm2 are investigated, respectively. We find that such resistive ITO/p-GaN junction can effectively prevent the holes from reaching the sidewalls for µLEDs with smaller size. Furthermore, such confinement of injection current also facilitates the hole injection into the active region for µLEDs. Therefore, the surface-defect-caused nonradiative recombination in the edge of mesa can be suppressed. Meantime, a reduction of current leakage caused by the sidewall defects can also be obtained. As a result, the measured and calculated external quantum efficiency (EQE) and optical output power for the proposed LED with small sizes are increased.We propose and demonstrate a high-performance wavelength-switchable erbium-doped fiber laser (EDFL), enabled by a figure-8 compound-ring-cavity (F8-CRC) filter for single-longitudinal-mode (SLM) selection and a polarization-managed four-channel filter (PM-FCF) for defining four lasing wavelengths. We introduce a novel methodology utilizing signal-flow graph combined with Mason's rule to analyze a CRC filter in general and apply it to obtain the important design parameters for the F8-CRC used in this paper. By combining the functions of the F8-CRC filter and the PM-FCF assisted by the enhanced polarization hole-burning and polarization dependent loss, we achieve the EDFL with fifteen lasing states, including four single-, six dual-, four tri- and one quad-wavelength lasing operations. In particular, all the four single-wavelength operations are in stable SLM oscillation, typically with a linewidth of less then 600 Hz, a RIN of ≤-154.58 dB/Hz@≥3 MHz and an output power fluctuation of ≤±3.45%. In addition, all the six dual-wavelength operations have very similar performances, with the performance parameters close to those of the four single-wavelength operations, superior to our previous work and others' similar work significantly. SM-102 Finally, we achieve the wavelength-spacing tuning of dual-wavelength operations for photonic generation of tunable microwave signals, and successfully obtain a signal at 23.10 GHz as a demonstration.Gapped systems with glide symmetry can be characterized by a Z2 topological invariant. We study the magnetic photonic crystal with a gap between the second and third lowest bands, which is characterized by the nontrivial glide-Z2 topological invariant that can be determined by symmetry-based indicators. We show that under the space group No. 230 (I a3¯d), the topological invariant is equal to a half of the number of photonic bands below the gap. Therefore, the band gap between the second and third lowest bands is always topologically nontrivial, and to realize the topological phase, we need to open a gap for the Dirac point at the P point by breaking time-reversal symmetry. With staggered magnetization, the photonic bands are gapped and the photonic crystal becomes topological, whereas with uniform magnetization, a gap does not open, which can be attributed to the minimal band connectivity exceeding two in this case. By introducing the notion of Wyckoff positions, we show how the topological characteristics are determined from the structure of the photonic crystals.We demonstrated an eye-safe diamond Raman laser intra-cavity pumped by the 1.3 μm fundamental field for the first time, to the best of our knowledge. The first-Stokes laser at 1634 nm was converted from the 1342 nm fundamental laser, which was produced by an in-band pumped double-end diffusion-bonded a-cut NdYVO4 crystal. Under an incident pump power of 21.2 W and an optimal pulse repetition frequency of 25 kHz, the maximum average output power of 2.0 W was obtained with the pulse duration of 5.7 ns and the peak power of 14 kW. The first-Stokes emission was found to be near diffraction limited (M2 ≈ 1.3) and to have a narrow linewidth (∼0.05 nm FWHM; instrument limited).We propose a near-infrared image recovery method based on modulation instability in the photorefractive semiconductor CdZnTeV. The formation mechanism of modulation instability in CdZnTeV is discussed, and the theoretical gain model is derived. Theoretical results of optical image recovery at 1 µm and 1.5 µm wavelengths demonstrate that the maximum cross-correlation gain is 2.6 with a signal to noise intensity ratio of 0.1. These results suggest that our method could be one of potential aids for near-infrared imaging.We report on the first sub-100 fs mode-locked laser operation of a Tm3+-doped disordered calcium lithium tantalum gallium garnet (TmCLTGG) crystal. Soliton mode-locking was initiated and stabilized by a transmission-type single-walled carbon nanotube saturable absorber. Pulses as short as 69 fs were achieved at a central wavelength of 2010.4 nm with an average power of 28 mW at a pulse repetition rate of ∼87.7 MHz. In the sub-100 fs regime, the maximum average output power amounted to 103 mW.We present a proof-of-concept experiment where the absorbance spectra of suspensions of plasmonic nanoparticles are accurately reconstructed through the photothermal conversion that they mediate in a microbubble resonator. This thermal detection produces spectra that are insensitive towards light scattering in the sample, as proved experimentally by comparing the spectra of acqueos gold nanorods suspensions in the presence or absence of milk powder. In addition, the microbubble system allows for the interrogation of small samples (below 40 nl) while using a low-intensity beam (around 20 µW) for their excitation. In perspective, this system could be implemented for the characterization of turbid biological fluids through their optical absorption, especially when considering that the microbubble resonator naturally interfaces to a microfluidic circuit and may easily fit within portable or on-chip devices.Tiny mismatches in timing, phase, and/or amplitude between in-phase (I) and quadrature (Q) tributaries in an electro-optic IQ modulator, namely IQ imbalance, can severely affect high baud-rate and/or high modulation-order signals in modern coherent optical communications systems. To maintain such analog impairment within the tight penalty limit over wavelength and temperature during the product lifetime, in-service in-field monitoring and calibration of the IQ imbalance, including its frequency dependence, become increasingly important. In this study, we propose a low-complexity IQ monitoring technique based on direct detection with phase retrieval called a single-pixel optical modulation analyzer (SP-OMA). By reconstructing the optical phase information lost during the detection process computationally via phase retrieval, SP-OMA facilitates the in-service in-field monitoring of the frequency-dependent imbalance profile without sending dedicated pilot tones and regardless of any receiver/monitor-side IQ imbalance. The feasibility of SP-OMA is demonstrated both numerically and experimentally with a 63.25-Gbaud 16QAM signal.The resolution of conventional imaging systems is inherently restricted by the diffraction limit. To surpass this diffraction barrier, a scheme using an external aperture modulation subsystem (EAMS) and related deep learning network (DLN) is presented in this paper. The EAMS facilitates the realization of various image acquisition strategies and related DLN architectures. In the specific scenario of 3-aperture modulation strategy, the capabilities of this approach are validated both in numerical simulations and experiments. The results show that both the resolution enhancement ability and the image fidelity can be improved by just adding one label data. This framework proposed here provides a more general way to further explore the ability of DLN-based method to surpass the diffraction limit, and permits a rapid data acquisition that enables new opportunities for the training data collection and further super resolution imaging of label-free moving objects, such as living cells.Quantum key distribution (QKD) employed orbital angular momentum (OAM) for high-dimensional encoding enhances the system security and information capacity between two communication parties. However, such advantagesare significantly degraded because of the fragility of OAM states in atmospheric turbulence. Unlike previous researches, we first investigate the performance degradation of OAM-based QKD by infinitely long phase screen (ILPS), which offers a feasible way to study how adaptive optics (AO) dynamically corrects the turbulence-induced aberrations in real time. Secondly, considering the failure of AO while encountering phase cuts, we evaluate the quality enhancement of OAM-based QKD under a moderate turbulence strength by AO after implementing the wrapped cuts elimination. Finally, we simulate that, with more realistic considerations; real-time AO can still mitigate the impact of atmospheric turbulence on OAM-based QKD even in the large wind velocity regime.Research towards practical applications of ghost imaging attracts more and more attention in recent years. Signal-to-noise ratio (SNR) of bucket results thus quality of images can be greatly affected by environmental noise, such as strong background light. We introduce temporal cross-correlation into typical ghost imaging to improve SNR of bucket value, taking temporal profile of illumination pulses as a prior information. Experimental results at sunny noontime verified our method, with the imaging quality greatly improved for the object at a distance of 1.3km. We also show the possibility of 3-dimensional imaging, experimentally.Antireflection sub-wavelength structures (SWSs) on ZnS were designed and ZnS SWSs with HfO2 protective film were prepared, and their properties in long-wave infrared applications were examined and compared to AR coatings. The SWS has good antireflection performance and exhibits less polarization sensitivity than the AR coating. At temperatures above 500 °C, the SWS with HfO2 protective film has a better thermal endurance property than the multilayer AR coating. Moreover, the HfO2 protective film significantly improved the mechanical properties of the ZnS SWS and was similar to HfO2 covered AR coating when the HfO2 film was not broken. This study shows that the ZnS SWS with HfO2 protective film has promising application prospects in infrared optical windows.