Machine Learning-Based Algorithm for the Design of Multimode Interference Nanodevices

Multimode Interference (MMI) device is a useful optical component for optical power splitter/combiner and router applications. In this paper we present high precision calculation results on the optimum position of self-images in an MMI and their variation due to wavelengths, for WDM applications. We show that the commonly used MMI self-image position calculation methods, using the beat length of two lowest order modes or effective MMI width approximation, lead to significant deviations from the optimum self-image position. We calculate the optimum position of the self-image by finding the maximum value of overlap integral of total MMI field, comprised of all MMI modes, with the total field at the input of the MMI device. In addition, for the optimum output power coupling distance for MMI, we calculate the overlap integral of the total MMI field with the output waveguide field. Both these methods give approximately the same optimum length. We obtain up to 60 um difference in optimum self-image position for a Si MMI (width =15 ~ 30 um), and refractive index difference of 0.02 between core and cladding, from the approximations based methods. We also calculate the variation of this image position in 1.50 um to 1.60 um wavelength region. We show that the optimum image position is strongly dependent on wavelength, with up to 100 um variations in this wavelength range. In addition, we show that there is a significant variation in this self image position with MMI widths, at points where a new power carrying mode is added.

In this paper, the design of low-loss multimode interference (MMI) couplers is reported. The proposed devices can be used as power splitters or combiners and are based on lithium niobate on insulator (LNOI) technology, a promising emerging platform for the realization of integrated optical devices. We consider 1×N MMI splitters and N×1 combiners, with N being the number of output/input ports. We define the design and the optimization criteria to achieve the best performances in terms of insertion loss and output power uniformity over a large wavelength range (i.e., from 1500 to 1600 nm). In particular, we investigate seven configurations of MMI couplers with N ranging from 2 to 8. The insertion loss for all the designed MMI couplers with N ranging from 2 to 8 varies from 0.018 to 0.41 dB, while the uniformity for all MMI splitters ranges from 0.020 to 0.335 dB across the considered wavelength range. The impact of the amplitude and phase errors on the transmittance of MMI combiners with N ranging from 2 to 8 input ports shows that the transmittance variation is less than 1.5 %, indicating high robustness and reliable performance in various photonic applications. We compare our MMI couplers results with those of the state-of-the-art based on different material platforms, including LNOI, obtaining much lower insertion losses.

A wavelength 0.85μm-based optical power splitter designed with Multi Mode Interference (MMI) by ion exchange on K9 glass was introduced. The waveguide material is K9 glass made in China and formed by K + -Na + pure melt salt ion exchange method. The grade index profile of planar ion-exchanged waveguide on K9 was studied and accorded with erfc function through compare of experimental and theoretic index profiles. The fabrication process of planar ion-exchanged waveguide device was described. The basic theory of 1×8 MMI optical power splitter was illuminated by using guided-model propagation analysis. The working wavelength is 0.85μm, and the structure parameters of 1×8 MMI splitter were designed. The core pitch on this chip is chosen as 250μm to take the fiber connections into account, and the typical cladding diameter of optical fibers as 125μm. The critical parameters in the fabrication of the MMI power splitter are the multimode section width and length. In general the key performance specifications of the optical power splitter are insertion loss and uniformity. The output performances and the refractive index change's influence of the device were simulated by Bear Propagation Method (BPM). The uniformity was 0.93 × 10 -2 dB, the average insertion loss was 9.12dB, and the maximal insertion loss was 9.14dB. The result shows that the advantages of the method include low loss, ease of fabrication, and low material cost.

Design and analysis of polarization independent MMI based power splitter for PICs

High-performance and compact power splitters are fundamental components in on-chip photonic integrated circuits (PICs). We propose a silicon-based power splitter based on a subwavelength grating (SWG)-assisted multimode interference (MMI) structure. To shorten the device size and enhance the device performance, an inverse-tapered SWG is embedded in the central region of the MMI and two rows of uniform SWG are embedded on both sides, together with two right-angled cutting structures on the input side. According to the results, the MMI length was obviously reduced to 3.2 μm (5.2 μm for conventional MMI structure under the same waveguide width), while the insertion loss (IL) and reflection loss were 0.08 dB and <−35 dB, respectively. Moreover, the allowable working bandwidth could be extended to 560 nm by keeping IL <0.6 dB, covering the whole optical communication band. On the basis of these features, we believe that such a power splitter is very promising for building on-chip large-scale PICs where power splitting is indispensable.

In this paper, we propose a novel 1 to N optical power splitter and a 1 to N optical switch for a multi-core fiber (MCF) with N circularly aligned cores. The splitter and the switch are based on the multimode interference (MMI) effect inside a ring core fiber. The MMI effect will convert one image into N output images in the ring and therefore, the ring shape MMI coupler can act as a 1 to N power splitter. These images will have different phases. If two ring shape MMI couplers are used and a tunable phase shifter array and a fixed phase shifter array are placed between them, by properly setting the phases of the N images in the middle of the MMI couplers, the images will converge to one output port of the 2nd MMI coupler. The output port number can be changed by tuning the phase shifters. In this way, the input signal at one of the cores of the MCF can be switched to the other core, and a 1 to N switch can be realized. In the analysis, it is found that only one control parameter is required for the phase adjustment of the tunable phase shifter array in order to achieve the switching between the cores.

We propose the novel structure of an interferometric biosensor based on multimode interference (MMI) waveguides. We present the design of the biosensor using eigenmode expansion (EME) method in accordance with the requirements and standards of today's photonic technology. The MMI structures with a 90 nm Si3N4 core are used as power splitters with 5 outputs. The 5 high-resolution images at the end of the multimode region show high power balance. We analyze the coupling efficiency of the laser source with the structure, the excess loss and power imbalance for different compact MMI waveguides with widths ranging from 45 μm to 15 μm. For a laser source with a tolerance of ±1mm in linearization we could achieve a coupling efficiency of 52%. MMI waveguides with tapered channels show excess loss values under 0.5 dB and power imbalance values under 0.08 dB. In addition, we show that for a 10 nm deviation of the source wavelength from its optimal value and for a 10 μm deviation of the MMI length from its optimal value, the performance of the MMI waveguides remains acceptable. Finally, we analyze the power budget of the whole biosensor structure and show that it is sufficient for the proper operation of this device.

An InGaAsP/InP variable power splitter utilizing the multimode interference (MMI) and the linear electro-optic (LEO)effect is designed and analyzed. The splitter consists of two MMI waveguides and phase-shifting waveguide sectionbetween them. The input MMI waveguide acts as a 3-dB splitter for the TE input signal. In the phase-shifting waveguides,the relative phase of split input signals is changed by using the LEO effect. The output MMI waveguide combines thephase-modulated signals at output ports. Depending on the amount of phase change induced by reverse bias voltages of 02.5 V, the splitting ratio varies from 1000 to 50:50 continuously. Keywords: Multimode interference, Splitter, Variable splitting ratio, Linear electrooptic effect, Schottky contact 1. INTRODUCTION Power splitting is the fundamental function for optical integrated circuits. During the past several years various types ofpower splitters have been reported. Especially power splitters using the multimode interference (MM!) have attracted agreat deal of interest because they can be made with more predictable and accurate splitting ratio than y-branch or fibersplitters. In addition they show several important characteristics like other MMI devices such as simple structure, lowexcess loss, easy fabrication and large fabrication tolerance, insensitive polarization dependence, and integratibility withother photonic devices.The splitting ratio of MM! splitters can be determined by choosing appropriate position and number of input and outputports of the multimode waveguide, but it is limited to a certain set of values. Recently MMI splitters with tapered mutimodewaveguides have been suggested to have the free selection of splitting ratio' .

The optimization of Adaptive Data Rate (ADR) mechanisms is fundamental to the energy efficiency and scalability of LoRaWAN networks. However, implementing intelligent control algorithms on resource-constrained Internet of Things (IoT) edge devices remains a significant challenge. This paper proposes and evaluates a novel mechanism based on a surrogate model for End Devices (EDs), which employs a Multi-Layer Perceptron (MLP) artificial neural network to adjust the following transmission parameters: Spreading Factor (SF), Transmission Power (TP), and the number of measurement packets, denoted as M. The MLP network was trained on a dataset generated by a pre-existing expert system, and its fidelity was rigorously validated via K-Fold cross-validation, achieving a Coefficient of Determination (R²) exceeding 0.92. Furthermore, a complexity analysis quantified the model’s low computational cost, revealing a memory footprint of 17.77 KB and an inference cost of 8,832 floating-point operations (FLOPs). The comparative analysis reveals that while the fuzzy inference system (FIS) it emulates may be more efficient in moderate-precision scenarios, the MLP’s architectural advantage for hardware execution positions it as a promising solution for implementation at the edge of LoRaWAN-based IoT systems.

The multimode power splitter plays an essential role in on-chip mode-division multiplexing systems. In this work, a broadband dual-mode optical power splitter based on the self-imaging effect in the multimode interference (MMI) engineered by bricked subwavelength gratings (BSWGs) is proposed. The dual-mode power splitter is optimized by combining the 3D finite difference time domain (FDTD) and the particle swarm optimization (PSO) method. For the input T E 0 mode, the insertion loss (IL) and the imbalance (IB) are lower than 0.55 dB and 0.65 dB, while the IL and IB for the input T E 1 mode are, respectively, lower than 0.7 dB and 0.37 dB over 150 nm bandwidth in the wavelength range of 1.5–1.65 µm. In addition, the cross talk (CT) is lower than − 25 d B for the two modes over this wavelength range. Furthermore, the minimum feature size of the gratings is as large as 135 nm, and only a single etch step is required, which is beneficial for the fabrication.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Mehdi Tajaldini, Mohd Zubir Mat Jafri; Arbitrary-ratio power splitter based on nonlinear multimode interference coupler. AIP Conference Proceedings 24 April 2015; 1657 (1): 140005. https://doi.org/10.1063/1.4915239 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search

A novel InP-based metal-coated sidewall, hybrid plasmonic multimode interference (MCS-HP-MMI) power splitter has been proposed. Based on two methods of multimode interference self-imaging and finite difference time domain simulations, a 1 × 2 MCS-HP-MMI power splitter was numerically analysed and compared with an HP-MMI power splitter with the same specifications showing 70% reduction in length due to the negative Goos–Hanchen shift in the metal-coated sidewalls of the MCS-HP-MMI power splitter. The width and layer stack specifications of the device were optimised using response surface methodology to minimise the multimode interference length and maximise the optical power transmission. The total optical power transmission of 98% was achieved for an MCS-HP-MMI width and length of 662 and 190 nm, respectively, with a wavelength of 1550 nm.

Silicon will play a practical role in the future of optoelectronic devices. Silicon microelectronics fabrication techniques can be largely exploited to fabricate low-loss and high volume optical devices. In this paper, we report the concept and realization of new two-dimensional 1x16 and 1x32 array waveguide optical power splitters that offer the possibility of a free choice of the output power ration in silicon-on-insulator (SOI). The power splitters compose one dimensional multimode interference (MMI) optical power splitter and multi-layers coupler at wavelength at 155 (mu) m. According to the design, we can reduce the size of SOI power splitters waveguide without increasing propagation loss, efficiently. The results achieved show a remarkable improvement with respect to those of classical MMI power splitters.

Free choice of splitting ratio is one of the main properties of a power splitter required in integrated photonics, but conventional multimode interference (MMI) power splitters can only obtain a few discrete ratios. This Letter presents both numerical and experimental results of an arbitrary-ratio 1×2 MMI power splitter, which is constructed by simply breaking the symmetry of the multimode region. In the new device, the power splitting ratio can be adjusted continuously from 100:0 to 50:50, while the dimension of the multimode section stays in the range of 1.5×(1.8-2.8) μm. The experimental data also indicate that the proposed arbitrary-ratio splitter keeps the original advantages of MMI devices, such as low excess loss, weak wavelength dependence, and large fabrication tolerance.

We propose an ultra-compact multimode interference (MMI) power splitter based on the Kerr nonlinear effect from simulations using modal propagation analysis. Crystalline polydiacetylene is used as the core layer to allow for the creation of a power splitter with a high number of outputs with the shortest possible multimode waveguide length operating in the nonlinear regime. The 11 high-contrast, high-resolution images at the end of the multimode waveguide in the simulated power splitter have a high power balance, whereas access to a high number of self-images is not possible under the linear regime in the proposed length range. The compact dimensions and ideal performance of the device are established according to optimized parameters. The proposed regime can be extended to the design of M × N power splitters. The results of this study indicate that nonlinear modal propagation analysis solves the miniaturization problem for all-optical devices based on MMI couplers to achieve multiple functions in a compact planar integrated circuit and also overcomes the limitations of previously proposed methods for nonlinear MMI. The results are verified using a numerical method.