dB Power Splitter Research Articles

A High-Gain Directional 1 × 8 Planar Antenna Array for 2.4GHz RFID Reader Applications

This research paper deals with a directional high gain PCB [Formula: see text] antenna array for 2.4[Formula: see text]ISM band utilizations. To achieve this antenna array, a well-matched equal-split 9[Formula: see text]dB-power splitter is designed and integrated with the suggested antenna array. It exhibits a wide operating range of 506[Formula: see text]MHz (2.022–2.528[Formula: see text]GHz) and splits the feed power to 8 equal-in-phase output quantities. Then eight identical patch elements with good reflection coefficient, high gain and excellent radiation efficiency are connected at the eight-output ports of the 1 × 8-power divider in order to obtain an array antenna consisting of eight radiating elements. A quarter-wave impedance adapter is utilized to obtain a perfect matching of impedance between patches and the power divider. The suggested directional antenna resonates at 2.4[Formula: see text]GHz with good impedance matching via offering reflection coefficient [Formula: see text][Formula: see text]dB and voltage standing wave ratio (VSWR) of 1.16. Moreover, it offers good radiation traits like the enhanced gain of 14.76[Formula: see text]dB, an excellent radiating efficiency equals about 98.86% and a directional radiation pattern. Initially, the proposed planar directional antenna array has been designed and simulated utilizing high-frequency structure simulator (HFSS) EM simulation tool, the results are validated with another simulation tool via computer simulation technology (CST) software. This printed antenna array is a potential candidate to operate at around 2.4[Formula: see text]GHz for RFID reader utilizations due to its outstanding impedance and radiation characteristics.

Low loss and ultra-broadband design of an integrated 3 dB power splitter centered at 2 µm.

Because chemical gas is sensitive to absorption in the 2µm band, and 2µm matches the absorption band of the remote sensing material, many remote sensors and optical sensors are designed to operate in the 2µm wavelength region. In this paper, we designed an integrated 3dB power splitter centered at 2µm. The study of this device is built on a silicon-on-insulator (SOI) platform. We introduced a subwavelength grating (SWG) to improve the performance of the device. We used the three-dimensional finite-difference time-domain (3D FDTD) method to analyze the effect of the structure on the power splitter. The insertion loss (IL) of the fundamental TE mode is only 0.04dB at 2µm and its bandwidth of IL <0.45d B is 940nm (1570-2510nm). It is suitable for multidomain and all-band photonic integrated circuits at 2µm.

Photonics inverse-designed compact dual-mode 3 dB power splitter for on-chip MDM systems

Optical power splitters are fundamental devices in on-chip optical systems, enabling coherent optical modulation through beam splitting and combining. Despite many mature theories and devices for power splitting in the single-mode scenario, achieving compact 3 dB power splitters in the multimode regime remains challenging. Here we present a compact dual-mode 3 dB power splitter for mode-division multiplexing (MDM) systems. The device supports both TE0 and TE1 modes of power splitting and maintains the mode order invariant. Our design incorporates the adjoint variable method (AVM) and level-set method to create a device structure that is compact and single-connected. The device features a footprint of 10 μm × 3.4 μm, with a minimum feature size larger than 200 nm to ensure compatibility with standard silicon on insulator (SOI) processes. Experimental results show that the insertion loss is 0.7 dB for the TE0 mode and 1.1 dB for the TE1 mode at the wavelength of 1550 nm. The proposed device may hold potential in on-chip MDM technology, such as multimode optical attenuators and switches, with compact size and high performance.

Ultra-broadband 1 × 2 3 dB power splitter using a thin-film lithium niobate from 1.2 to 2 µm wave band.

The 3 dB power splitters are fundamental building blocks for integrated photonic devices. As data capacity requirements continue to rise, there is a growing interest in integrated devices that can accommodate multiple spectral bands, including the conventional O-, C-, and L-bands, and the emerging 2 µm band. Here we propose and experimentally demonstrate a 3 dB power splitter based on adiabatic mode evolution using a thin-film lithium niobate, with ultra-broadband operation bandwidth from 1200 to 2100 nm. The fabricated power splitter exhibits low insertion losses of 0.2, 0.16, and 0.53 dB for wavelengths at 1310, 1550, and 2000 nm, respectively. The measured 1 dB bandwidth covers 1260-1360, 1480-1640, and 1930-2030 nm, which we believe that the proposed device is capable of operating in both O-, C-, L-, and 2 µm bands.

Demonstration of a High‐Performance 3 dB Power Splitter in Silicon Nitride Loaded Lithium Niobate on Insulator

AbstractLithium niobate on insulator (LNOI) has emerged as a promising platform for photonic integrated circuits (PICs) due to the excellent electro‐optic (EO) properties of lithium niobate (LN). However, such a platform still lacks many critical passive components with superior performance for constructing PICs. The 3 dB power splitters are one of the important passive components in PICs for separating and combining optical energy to construct the other crucial photonic devices such as Mach–Zehnder modulators, optical switches, and optical phased arrays, et al. In this contribution, an ultra‐broadband and compact 3 dB power splitter is proposed and demonstrated using a tapered subwavelength grating (SWG)‐assisted Y‐branch on a silicon nitride (Si3N4) loaded LNOI platform. The SWG is used to alleviate fabrication challenges and reduce radiation loss while increasing the evanescent coupling. The simulation result shows an excellent operation bandwidth of 800 nm (from 1.2 to 2.0 µm) at the insertion loss (IL) of 0.12 dB. The proposed device with a compact footprint (9.6 × 3 µm2) is finally fabricated on a Si3N4 loaded LNOI platform, and the experimental result shows the IL of &lt;0.2 dB in the wavelength ranges from 1.5 to 1.6 µm, which makes it suitable for broadband PICs required for future communication systems.

Silicon MMI-based power splitter for multi-band operation at the 1.55 and 2 µm wave bands

Multimode interference (MMI)-based power splitters are fundamental building blocks for integrated photonic devices consisting of an interferometer structure. In order to forestall the 'capacity crunch' in optical communications, integrated devices capable of operating in multiple spectral bands (e.g., the conventional telecom window and the emerging 2 µm wave band) have been proposed and are attracting increasing interest. Here, we demonstrate for the first time, to the best of our knowledge, the realization of a dual-band MMI-based 3 dB power splitter operating at the 1.55 and 2 µm wave bands. The fabricated power splitter exhibits low excess losses of 0.21 dB and 0.32 dB with 1 dB bandwidths for 1500-1600 nm and 1979-2050 nm, respectively.

Design and Preparation of Broadband 3 dB Power Splitter with Compact Size and Low Loss

Design and Preparation of Broadband 3 dB Power Splitter with Compact Size and Low Loss

Design of an ultra-broadband and low-loss 3 dB power splitter from the 1.25 to 2.04 µm wave band.

As a key component of the beam splitting and combining in photonic integrated circuits, an optical power splitter requires the characteristics of compactness, broadband, and low loss. Here, we propose a 1×2 ultra-broadband 3dB power splitter with a 5µm long beam splitting area, based on the structure of a subwavelength grating. The 0.45dB bandwidth of the TE mode achieves 790nm from 1.25 to 2.04µm. This power splitter has a large fabrication tolerance, exceeding more than 30nm (±15n m) and obtains the desired power ratio. It is suitable for high-speed and large-capacity communication, wavelength division multiplexing systems, and other multi-wave interconnection applications.

Design and manufacture of an all-polymeric integrated multimode interferometer for visible photonics.

This work demonstrates an integrated multimode interferometer (MMI) based on a fully polymeric platform and optimized for visible range operation. The dimensions of a 2×2 MMI are first calculated analytically and simulated using finite elements method. The devices are manufactured using two layers of negative tone photoresists. The top layer is patterned by e-beam lithography demonstrating the adaptability of this material, naturally designed to respond to UV radiation. Fabrication tolerance was smaller than 100 nm. Devices were optically characterized with a 635 nm input source and the best performance for a 3 dB power splitter was found at an interferometric cavity dimension of 10.5 × 190.68 µm. Other interferometric lengths were characterized to establish a process design kit that allows future use of this platform in more complex photonic integrated circuits architectures.

Ultra-compact polarization-independent 3 dB power splitter in silicon.

We experimentally demonstrate an ultra-compact polarization-independent 3 dB power splitter on the silicon-on-insulator platform. Subwavelength structure engineering is employed to balance the coupling coefficients of TE and TM polarizations as well as a footprint reduction. The device possesses ultra-compact (1.2µm×2.62µm) and polarization-independent features with an operating bandwidth over 50 nm (from 1540 to 1590 nm).

Ultra-broadband 3 dB power splitter from 1.55 to 2 µm wave band.

Extending the optical communication wavelengths to 2 µm can significantly increase data capacity. Silicon photonics, which is a proven device integration technology, has made rapid progress at 2 µm recently. As a fundamental functional element in the photonic design kit, the 3 dB power splitter has been extensively studied in both the 1.55 µm and 2 µm regime. While the device is highly desirable to operate over both wave bands, the large waveguide dispersion in silicon makes it challenging. In this work, we demonstrate an ultra-broadband power splitter on silicon, which has a 0.2 dB bandwidth exceeding 520 nm from 1500 to 2020 nm according to simulations. The beam splitter is realized by a triple tapered Y-junction, and its operational bandwidth is greatly increased by subwavelength grating structure. The device has an ultra-compact footprint of only 3µm×2µm. Due to the limitations on the setup and coupling technique, we measure the device bandwidth in 1.55 µm and 2 µm wave bands. The device insertion loss is measured to be below 0.4 dB from 1500 to 1620 nm and from 1960 to 2020 nm, respectively. According to these results, the proposed device is believed to be capable of operating over a broadband from 1.55 µm and 2 µm wavelengths.

Bidirectional grating based interleaved angled MMI for high-uniformity wavelength division (de)multiplexing and surface-normal fiber packaging.

We propose and experimentally demonstrate a vertical fiber interfacing interleaved angled multimode interference (MMI) coupler for wavelength-division multiplexing (WDM) applications. This four-channel WDM device comprises two 1×2 angled MMI couplers and a bidirectional grating-based Mach-Zehnder interferometer (MZI) structure. In the MZI optical interleaver, the uniform bidirectional grating functions as both the perfectly vertical grating coupler and the 3 dB power splitter. Benefitting from the flat-top coupling spectrum of the grating coupler, a high-uniformity wavelength-division (de)multiplexing can be achieved with a simulated insertion loss of 3.15-3.36 dB (the nonuniformity of 0.22 dB). The angled MMIs (AMMIs) are designed and optimized using the eigenmode expansion method. For wavelength matching between the MZI and AMMIs, the circuit simulation model of the interleaved AMMI is built by importing the S-parameter matrices of all the optical components extracted from the physical level simulations. The device was fabricated using standard CMOS technology and all the features were patterned with the 193-nm deep-UV lithography. Experimental results obtained without thermal tuning are in good agreement with the simulation results. The device exhibits an insertion loss of 4.5-4.65 dB (nonuniformity of 0.15 dB), channel spacing of 10 nm, and cross talk of -(21.62-26)dB.

Proposal for metal–insulator–metal plasmonic power splitter and demultiplexer suitable for implementation in optical switches

The authors propose a nanoplasmonic structure based on metal–insulator–metal (MIM) waveguides which consists of a 3 db power splitter and a side-coupled nanocavity placed between its two output ports. The proposed structure is analysed by the resonant theory and dispersion relation. Transmission spectra of the presented device are also extracted using the finite difference time domain method. Numerical simulations demonstrate that the structure operates as a band-stop filter in each output channel. Moreover, the resonance wavelengths can be tuned by adjusting the geometrical parameters of the nanocavity. Meanwhile, the authors developed the cavity and added an extra stub to it to append a new stopband to the output spectrum. Each resonance wavelength can be easily manipulated by changing the widths of the nanocavity and the added stub. In the end, by choosing two different lengths for the side-coupled cavities, the authors convert the power splitter into a wavelength division multiplexer. These introduced MIM, the authors proposed here, may have various meaningful applications in nanoscale high-density photonic circuits such as optical switches, logic plasmonic circuits and slow-light devices.

Integrated Dual-Mode 3-dB Power Splitter Based on Multimode Interference Coupler

We design and experimentally demonstrate a dualmode 3 dB power splitter based on the self-imaging effect in a taper-assisted multimode interference (MMI) coupler. The quality reduction of the two mirrored half-power images of the input field due to accumulated high-order eigenmodes phase error will degrade the performance of dual-mode power splitter. We propose an eigenmode-selective-excitation method to suppress the excitation of high-order eigenmodes in the MMI. By optimizing the geometric parameters and injection position of the input taper waveguide, we realize power ratios of 95.9 % and 94.2 % for the lowest three and five eigenmodes when input TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> modes, respectively. The fabricated device occupies a footprint of 5 μm × 86.5 μm with 5.2 μm assisted tapers. The measured excess losses and crosstalks for both modes are less than 0.76 dB and -20.5 dB, on average, over the observable 60 nm bandwidth, respectively, which are consistent with the numerical simulations.

Ultra-Compact Broadband 2 × 2 3 dB Power Splitter Using a Subwavelength-Grating-Assisted Asymmetric Directional Coupler

An ultra-compact broadband 2 × 2 3 dB power splitter is proposed and demonstrated by utilizing a subwavelength- grating (SWG)-assisted asymmetric directional coupler. In the present design, a subwavelength grating is inserted into the straight coupling region of an asymmetric directional coupler, so that the refractive index and the dispersion properties of this structure are engineered for achieving an ultra-broad bandwidth and an ultra-compact footprint. For the present power splitter with a straight coupling region as short as 5.25 μm, the bandwidth is as large as 300 nm (1400~1700 nm) for achieving an imbalance of <; 0.4 dB and an excess loss of <; 0.33 dB for the fundamental transverse electrical (TE) mode. The fabricated splitter works well with an imbalance less than 0.5 dB and with an excess loss less than 1 dB in a broad wavelength-band from 1450 to 1650 nm.

Compact and broadband 2 × 2 optical switch based on hybrid plasmonic waveguides and curved directional couplers

In this paper, a compact, broadband, and CMOS compatible ${2} \times {2}$2×2 optical switch based on hybrid plasmonic waveguides (HPWs) and curved directional coupler is presented. The proposed coupler consists of a combination of straight and curved hybrid plasmonic waveguides. By using the ability of HPWs for confining the light wave in a sub-wavelength scale and the curved structure to decrease the wavelength dependence of the directional coupler, a 3 dB power splitter with a ${3}\,\,\textrm{dB} \pm 0.5$3dB±0.5 bandwidth of about 410 nm and a footprint of ${7.6}\,\,\unicode{x00B5}\textrm{m} \times {2}\,\,\unicode{x00B5}\textrm{m}$7.6µm×2µm is achieved. By exploiting this optimal power splitter in a Mach-Zehnder interferometer structure, a ${2} \times {2}$2×2 electro-optic switch with a broad bandwidth of 400 nm and a small footprint of ${33}\,\,\unicode{x00B5}\textrm{m} \times {2.5}\,\,\unicode{x00B5}\textrm{m}$33µm×2.5µm is realized, which denotes the widest bandwidth compared to the previously reported similar structures. The three-dimensional finite-difference time-domain simulation results show a switching speed of 0.15 THz for the proposed optical switch, while the extinction ratio, power consumption, and insertion loss are 20 dB, 95.2 fJ/bit, and 4 dB, respectively, at the central wavelength of 1550 nm.

Lithographic Mask Defects Analysis on an MMI 3 dB Splitter

In this paper, we present a simulation study that intends to characterize the influence of defects introduced by manufacturing processes on the geometry of a semiconductor structure suitable to be used as a multimode interference (MMI) 3 dB power splitter. Consequently, these defects will represent refractive index fluctuations which, on their turn, will drastically affect the propagation conditions within the structure. Our simulations were conducted on a software platform that implements the Beam Propagation numerical method. This work supports the development of a biomedical plasmonic sensor, which is based on the coupling between propagating modes in a dielectric waveguide and the surface plasmon mode that is generated on an overlaid metallic thin film, and where the output readout is achieved through an a-Si:H photodiode. By using a multimode interference 1 × 2 power splitter, this sensor device can utilize the non-sensing arm as a reference one, greatly facilitating its calibration and enhancing its performance. As the spectral sensitivity of amorphous silicon is restricted to the visible range, this sensing device should be operating on a wavelength not higher than 700 nm; thus, a-SiNx has been the material hereby proposed for both waveguides and MMI power splitter.

Ultra-directional high-efficiency chiral silicon photonic circuits

Chiral light matter interaction enables new fundamental researches and applications of light. The interaction has traditionally faced challenges in low directionality and efficiency based on spin orbit interaction of light in microscopic waveguides. It is pivotal to exploit photonic integrated circuits to efficiently engineer photonic chiral behavior. Here, we present ultra directional high efficient chiral coupling in silicon photonic circuits based on low order to high order mode conversion and interference. We show that the directionality of chiral coupling, in principle, can approach minus/plus 1 with circular polarization inputs, benefited from the underlying mechanism of complete destructive and constructive interference. The chiral coupling efficiency can exceed 70%, with negligible scattering to nonguided modes, much higher than conventional coupling mechanisms. Moreover, the chiral silicon photonic circuits can function as a perfect 3 dB power splitter for arbitrarily linear polarization inputs, and also open up the possibility of on chip chirality determination to further flourish the development of chiral optics.

Inverse design and demonstration of an ultracompact broadband dual-mode 3 dB power splitter.

An ultracompact broadband dual-mode 3 dB power splitter using inverse design method for highly integrated on-chip mode (de) multiplexing system is proposed and experimentally demonstrated. A dual-mode convertor based on subwavelength axisymmetric three-branch waveguide is utilized to convert TE0 and TE1 to three intermediate fundamental modes. The axisymmetric topology constraint of the nanostructures enables the optimized device to achieve a strict 50:50 splitting ratio over a broad wavelength range from 1.52 to 1.60 µm. The fabricated device occupied a compact footprint of only 2.88 µm × 2.88 µm. The measured average excess losses and crosstalks for both modes were respectively less than 1.5 dB and -20 dB from 1.52 to 1.58 µm for both TE0 and TE1, which are consistent with the numerical simulations.

Polarization-insensitive broadband 2 × 2 3 dB power splitter based on silicon-bent directional couplers.

We present and demonstrate a broadband and polarization-insensitive 2×2 3dB power splitters based on silicon-bent directional couplers (DCs). The working bandwidth can be from 1520 to 1630nm for both TE and TM polarizations, with an excess loss less than 1dB. The total size for the fabricated device can be as small as 50μm, and the measurement results show good agreement with the simulations.