New post from optoelectronic advance Discusses high-performance optical integrated circuits based on the reverse design method.
With the exponential growth of information and data, integrated optical circuits and chips have higher requirements for ultra-fast response time, ultra-small size, ultra-low power threshold, and high integration density. The photonic integrated circuit consists of a micro/nano structure and uses a photon instead of an electron as the information carrier. Conventional optical integrated circuits based on structures such as von Neumann mainly use regular or periodic structures, such as micro-ring resonators, photonic crystals (PCs), surface plasmon trains (SPPs), metamaterials, etc. Which causes the overall size of the circuit is large, usually up to hundreds of microns. Although the size of SPPs is small, their massive transmission loss still presents a huge limitation difficulty in achieving low power consumption. To achieve complex functions, conventional devices usually adopt non-linear materials. However, the discrepancy between the ultrafast response and the large nonlinear modulus of nonlinear materials leads to the discrepancy between the ultrafast response and the very low power consumption. So far, achieving high-performance photovoltaic integrated circuit with ultra-high density integration, ultra-fast response and ultra-low power consumption remains a major challenge.
Traditionally, designs of micro/nano-devices mainly rely on Finite Difference Time Domain Method (FDTD) and Finite Element Method (FEM) by solving Maxwell’s equations, but the methods usually involve a long process through iterative computation to improve structural parameters by tuning the parameters of the structures. nanoscale manually, such as the width of the waveguides, the diameter of the air holes and the size of the micro-rings, etc. The inverse design method, using algorithm technology to calculate unknown optical structures or optimize known structures based on expected functional properties, is more suitable for designing and optimizing optical micro/nanostructures. The reverse design method can improve the performance of a single device or enrich the function of the whole circuit, such as high-performance mesh couplers, wavelength polymorphism, power splitter, polarizing beam splitter, etc. Optical integrated circuit design and improvement is expected to break through the bottleneck of on-chip information processing capacity.
The authors of this paper have proposed and experimentally demonstrated an approach based on the reverse design method to achieve a high-density, ultra-fast, and very low-power photovoltaic integrated circuit. The research group has optimized the reverse design algorithm to meet the demand of improving the performance of the whole circuit. The advantage of the algorithm was the presence of an adjacent field distribution. The accompanying method requires a “one step drop” dielectric constant along the gradient descent direction, the gradient was calculated according to the objective function, and the dielectric constant was repeated along the gradient direction.
The circuit consists of three devices with two optical switches that control the input states of an XOR logic gate. The entire circle feature size was only 2.5 µm x 7 µm, and the single device size was 2 µm x 2 µm. The distance between two adjacent devices was as small as 1.5 μm, within the scale of the size of the wavelength. By scattering disordered nanostructures with an inverse design, the pattern field distribution of the signal light was altered. When the signal light is entered, it can be transmitted through the disordered nanostructures. Upon input of the control light, the mode field of the two lamps coherently overlapped, which changed the mode field distribution of the signal light and the control light, thus the signal light could not be transmitted through the disordered nanostructures. The theoretical response time of the all-optical switch with the reverse design was 100 fs, and the threshold energy of the control light was 10 fJ/bit, which is equivalent to the signal light of the all-optical switch. The response time of the logic gate was 20 fs. The research group also looked at the crosstalk problem through the whole integrated circuit optimization process. The circuit not only integrated three devices, but also realized the function of determining the results of two-digit logic signals. This work provides a novel idea for the design of an ultra-fast, ultra-low power consumption and high-density photonic integrated circuit.
A new all-encompassing switching method makes optical computing and communication systems more energy efficient
Huixin Qi et al, A high-performance photovoltaic integrated circuit based on the reverse design method, optoelectronic advance (2022). doi: 10.29026/oea.2022.210061
Provided by Compuscript Ltd
the quote: High-performance photonic integrated circuit based on the inverse design method (2022, June 22) Retrieved on June 22, 2022 from https://phys.org/news/2022-06-high-photonic-circuit-based-inverse.html
This document is subject to copyright. Notwithstanding any fair dealing for the purpose of private study or research, no part may be reproduced without written permission. The content is provided for informational purposes only.