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The increasing demand for higher data rates and small form factor equipment for optical networks is fuelling research on integrated optical devices with small footprint and broad bandwidth. Here, we present novel design approaches for grating couplers in the silicon and silicon nitride platforms that enable broadband operation and highly efficient coupling. Furthermore, we report experimental findings...
We report our advances in development of subwavelength engineered metamaterial structures in silicon waveguides, specifically high-efficiency fiber-chip couplers, ultra-broadband surface grating couplers and nanophotonic beam splitters, evanescent field waveguide sensors and on-chip Fourier-transform spectrometers.
Spatial eigenstates are a familiar part of optical waveguide theory. Such states enter and exit the waveguide as the same spatial state. As illustrated in Fig. 1. In the idealised case, a perfect waveguide, free of mode coupling, perturbations and ignoring chromatic dispersion, these spatial eigenstates also propagate with a single group-delay. However in reality, light propagation in multimode optical...
Grating fiber-chip coupler (GC) is a versatile scheme to couple light into submicron waveguides, particularly in SOI platform [1]. Typical GC is defined within a footprint of 10 × 10 μm to match the fiber mode field. The 10 μm wide waveguide is then adiabatically tapered (length ∼ 500 μm) down to a 400/500 nm single-mode waveguide. To reduce the taper length, focusing type grating was introduced and...
The dramatic progress in power-scaling of ultra-short pulse (USP) lasers and their continuous expansion use in industrial applications call for flexible and robust beam delivery systems (BDS) over several meters. Recently, a new branch of hollow-core photonic crystal fiber (HC-PCF) based on inhibited coupling (IC) mechanism has been proposed and successfully applied to demonstrate the delivery of...
Signal coordination is one of the most widely employed strategies to efficiently operate signal plans in a network. The impact on a network varies depending on signal plans as well as the spatial shape of coordination groups. Improper coordination groups may worsen the traffic flow and level of service Finding ideal decomposition points of an arterial is critical in a system-wide perspective. This...
A 6Gb/s 9.8pJ/b rotatable non-contact connector applicable to robot arms is developed. The proposed rotatable transmission line coupler (RTLC) has a wide bandwidth at all rotation angles. An interface bridge IC is also developed to transfer a wide range of interface signals from slow legacy ones to high-speed ones. The proposed system improves power efficiency by a factor of 3.7, space efficiency...
This paper presents a wideband high efficiency continuous class-F (CCF) power amplifier (PA) at mm-Wave frequencies for the first time. A tuned load with a high-order harmonic resonance network is used to shape the current and voltage waveforms for the proposed CCF CMOS PA. Further, a transformer with a tunable coupling-coefficient (ktune) is incorporated in the tuned load network to address the detrimental...
To study the relationship between the performance and the size of the filter, a W band rectangular waveguide bandpass filter was designed. First, a four cavity bandpass filter was designed, and then improved its structure to generate a transmission zero on both sides of the passband. The cross coupling structure reduces the rectangular coefficient by 25.7% and enhances out of band rejection. The simulation...
In this paper, we investigate the energy efficiency (EE) performance of optimal scheduling strategies in ultradense networks (UDNs). We consider a network deployment of base stations (BSs) based on a homogeneous Poisson Point Process (PPP), and assume users requests, modeled according to a space-time homogeneous Point Process (STPP), are to be served within a given service time. The objective is to...
In this paper, the resistor effect on isolation bandwidth of a compact Wilkinson power divider is studied. The discussion is based on an equal modified compact power divider on RO4003, with center frequency of 2.4 GHz. In this compact power divider, stepped impedance interdigital coupling sections were introduced to replace the quarter wavelength impedance transformer of Wilkinson power divider to...
Balanced/balanced-to-single-ended networks have been used widely in modern communication systems due to their ability of easy connection in balanced systems as well as differential-mode power division, common-mode suppression. Furthermore, filtering balanced or balanced-to-single-ended networks have become increasingly of interest for the advantages of multiple functions and compactness. In this paper,...
Millimeter-wave (mm-Wave) Massive Multiple Input Multiple Output (MIMO) at 60 GHz is a candidate of advanced wireless communications for indoor environment. Mm-Wave massive MIMO antenna with lower frequency with sectoring technique has been proposed in previous research. Also dual polarized configuration for MIMO in lower frequency and lower number of antenna. Massive MIMO at 60 GHz mm-Wave is not...
The terahertz waveguide directional coupler with double “tian-shape” is designed basing on the directional coupling principle of branch line. The branch lines closed to the waveguide width edge are bolding to increase stress and then the feasibility of processing will be improved. The coupler is analyzed and optimized by professional electromagnetic simulation software high-frequency structure simulator...
This paper presents new planar micromachined 5 pole bandpass filter topologies with narrow bandwidth and moderate insertion losses at 150 GHz. A 5 pole narrow band filter is presented at 150 GHz with 5˜6 dB of insertion losses with a fractional bandwidth of 2% and high rejection (≫40 dB).
Carrier aggregation supports an increased total bandwidth, data rate and utilization of available fragmented spectrum, where the latter is a core component of next generation Wi-Fi and Cellular networks, including 5G. Wireless communications receivers with intra-band non-contiguous CA, employing conventional complex mixers and base-band circuitry, are desirable, however risks of VCO injection pulling...
Robustness analysis method is proposed for rotorcraft pilot coupling with helicopter flight control system in loop. Combining with the lateral identification model of BO-105 helicopter, McRuer's pilot model, and the designed stability augmentation system, frequency domain model is established for rotorcraft pilot coupling analysis. μ analysis method and performance specifications in ADS-33E are adopted...
Modal dispersion severely limits data rates in multimode fiber (MMF) links. The use of principal modes (PMs) in lossless MMFs mitigates the impact of modal dispersion over a large bandwidth and permit effective multiplexing due to their orthogonal nature. However, in fibers with mode-dependent losses (MDL), the principal modes experience different losses and are no longer orthogonal. In this paper,...
Increased data rate requirements in short haul applications has enhanced the research on data transmission using graded-index multimode fibers (GI-MMF). Among the several optical launching techniques for exciting the fundamental mode in an MMF mode-field diameter matched twin-spot launching (MFDM-TSL) is a technique with much higher alignment tolerance. In this paper we study the influence of wavelength...
A low profile unidirectional UWB antenna for multi-service base stations is presented in this paper. The main goal of this article is to design a low profile UWB antenna with a very stable and unidirectional radiation pattern. The proposed design is based on exciting the fundamental mode of a planar structure composed of two metallic rings, applying the Theory of Characteristics Modes. The feeding...
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