ArticlePublisher preview available

Extraction of the optical properties of waveguides through the characterization of silicon‐on‐insulator integrated circuits

Authors:
  • St. Petersburg Electrotechnical University
To read the full-text of this research, you can request a copy directly from the authors.

Abstract and Figures

In the present work, a method to determine the optical waveguide properties of silicon‐on‐insulator (SOI) integrated circuits has been developed. According to the explicit relations between transfer functions of a microring resonator and the waveguide properties the inner optical parameters could be extracted. An increase in accuracy can be achieved by measuring the transfer functions of additional elements, such as a straight waveguide and a directional coupler. It is shown that the developed method allows one to determine the coupling coefficient, damping decrement, Bragg grating coupler efficiency, and waveguide dispersion with high accuracy. The obtained optical waveguide properties are used for modeling the transmission of a Mach–Zehnder interferometer which is used as a control element. The modeling results demonstrate a good agreement with the experimental characteristics. The developed method paves the way to local characterization of large‐scale SOI integrated circuits by using the aforementioned structures as reference elements.
This content is subject to copyright. Terms and conditions apply.
Received: 22 September 2022
|
Revised: 26 January 2023
|
Accepted: 2 March 2023
DOI: 10.1002/mop.33675
RESEARCH ARTICLE
Extraction of the optical properties of waveguides
through the characterization of silicononinsulator
integrated circuits
Alexander A. Ershov |Andrey I. Eremeev |Andrey A. Nikitin |
Alexey B. Ustinov
Department of Physical Electronics and
Technology, Saint Petersburg
Electrotechnical University LETI, St.
Petersburg, Russian Federation
Correspondence
Alexander A. Ershov, Department of
Physical Electronics and Technology,
Saint Petersburg Electrotechnical
University LETI, 5 Professora Popova,
St. Petersburg 197022, Russian
Federation.
Email: aaershov@etu.ru
Funding information
Ministry of Science and Higher Education
of the Russian Federation
Abstract
In the present work, a method to determine the optical waveguide properties
of silicononinsulator (SOI) integrated circuits has been developed. According
to the explicit relations between transfer functions of a microring resonator
and the waveguide properties the inner optical parameters could be extracted.
An increase in accuracy can be achieved by measuring the transfer functions
of additional elements, such as a straight waveguide and a directional coupler.
It is shown that the developed method allows one to determine the coupling
coefficient, damping decrement, Bragg grating coupler efficiency, and
waveguide dispersion with high accuracy. The obtained optical waveguide
properties are used for modeling the transmission of a MachZehnder
interferometer which is used as a control element. The modeling results
demonstrate a good agreement with the experimental characteristics. The
developed method paves the way to local characterization of largescale SOI
integrated circuits by using the aforementioned structures as reference
elements.
KEYWORDS
microring resonators, photonic integrated circuits, silicononinsulator technology
1|INTRODUCTION
Silicononinsulator (SOI) is a wellstudied technology
widely used for the complementary metaloxide
seminconductor (CMOS) compatible fabrication of elec-
tronic and photonic integrated circuits. This compatibil-
ity represents the principal requirement allowing for low
cost and largevolume production.
1
The photonic inte-
grated circuits fabricated with the SOI technology utilize
miniature silicon waveguide with a typical crosssection
of 500 × 220 nm
2
surrounded by silicon dioxide. This
geometry allows for a quasisinglemode propagation in
the telecommunication band. High refractive index
contrast typical for the SOI platform provides a small
bending radius and a high density of elements per chip
area. However, high index contrast imposes rigorous
requirements on the waveguide dimensions, even
nanometerscale roughness in the crosssection result
in noticeable variation in the performance character-
istics.
2,3
Combining the CMOS compatibility with high
index contrast makes SOI technology a favorable
platform for the fabrication of highdensity largescale
photonic integrated circuits.
4,5
Low insertionloss levels around 13dB/cm
5,6
in
combination with a very compact design result in various
passive photonic devices (resonators, filters, multiplexers,
Microw Opt Technol Lett. 2023;65:24512455. wileyonlinelibrary.com/journal/mop © 2023 Wiley Periodicals LLC.
|
2451
... Для независимого определения этих коэффициентов, а также дисперсионных свойств ФИС был предложен метод, основанный на измерении передаточных характеристик тестового набора элементов, а именно прямого микроволновода, волноводного ответвителя, микрокольцевого резонатора, а также интерферометра Маха-Цендера. Измерение передаточных характеристик такого набора тестовых элементов позволяет определить каждый из волноведущих параметров ФИС по отдельности [40]. Недостатком такого подхода является то, что он требует использования нескольких элементов, волноведущие свойства которых могут варьироваться из-за неоднородностей, обусловленных технологией изготовления [8,31]. ...
... Отметим, что полученное значение отличается от теоретического, которое на частоте 191.5 THz для кремниевых волноводов сечением 500 × 220 nm составляет 4.203. Как было показано в работах [31,40], такое отличие может быть обусловлено различием между реальными размерами волновода и проектируемыми. На заключительном этапе путем совмещения экспериментальных и теоретических характеристик были получены частотные зависимости, описывающие эффективность ввода и вывода сигнала. ...
... Для исследования влияния отжига на свойства волноведущих структур целесообразно использовать методы неразрушающего контроля оптических параметров. Для этого был использован метод, предложенный в [17]. В соответствии с этим методом на пластине изготавливаются наборы тестовых элементов, параметры которых исследуются до и после температурного отжига. ...
... Ввод и вывод излучения осуществлялся при помощи линзованных волокон (рис. 3), закреплен-Рис. 1. Шаблон тестовых элементов: апрямые волноводы; бволноводный ответвитель; вкольцевой резонатор Fig. 1 [17], были получены значения коэффициентов затухания α и связи κ, а также группового показателя преломления . g n Полученные в результате частотные зависимости параметров показаны на рис. ...
Article
Introduction . Silicon nitride is a highly promising material for fabrication of photonic integrated circuits (PICs). Plasma-enhanced chemical vapor deposition is a prospective method for large-scale industrial production of silicon nitride-based PICs. The disadvantage of this method, which limits its practical application, consists in high insertion losses in the telecommunication frequency band due to absorption on the Si–H and N–H bonds remaining from the film growth process. Thermal annealing is the most common method for breaking these bonds and reducing losses. Therefore, investigation of the impact of annealing on the optical properties of photonic integrated waveguides is an important research task. Aim . To investigate the effect of annealing treatment on the optical properties of PICs based on the silicon nitride films with different thicknesses obtained by plasma-enhanced chemical vapor deposition. Materials and methods . The work investigates the effect of annealing treatment on the optical properties of PICs based on the silicon nitride films with thicknesses of 200, 400 and 700 nm. To that end, the transmission characteristics of a set of test elements were measured using a high-definition component analyzer in the frequency range of 185…196 THz. Results . Frequency dependencies of loss and coupling coefficients, as well as the group index before and after annealing were extracted from the measured transmission characteristics of the test elements. It was found that waveguides on a 200-nm-thick film exhibited higher losses in comparison with the waveguides on thicker films. The waveguides with cross sections of 900 × 400 and 900 × 700 nm2 demonstrate the losses below 5 dB in the frequency range of 185…190 THz. A rapid increase in losses due to absorption on the N–H bonds was observed at the frequencies above 190 THz. The work shows that thermal annealing reduces insertion losses across the frequency range from 185 to 196 THz. The adequacy of extracted optical parameters is confirmed by comparing theoretical and experimental transmission characteristics of the ring resonator. Conclusion . The obtained results demonstrate that silicon nitride waveguides fabricated by the method of plasma-enhanced chemical vapor deposition require the stage of thermal annealing. Vacuum annealing at 600 °C for 30 min reduces insertion losses in the waveguides with cross sections of 900 × 400 and 900 × 700 nm ² down to 4 dB/cm in the frequency band from 185 to 196 THz.
... This study aims to fabricate silicon quantum wells on insulators using partial thermal oxidation of Silicon-on-Insulator (SOI) substrates. Notably, the advantages and characteristics of Silicon-On-Insulator (SOI) structures play a pivotal role in enabling this novel fabrication method [9][10][11]. ...
Article
Full-text available
The incorporation of nanostructures such as silicon nanocrystals into the oxide of an MOS structure has attracted significant interest in improving the performance of MOS-based devices. However, integrating crystalline silicon quantum wells into this structure remains a challenge due to the difficulties associated with growing a crystalline Si film on an amorphous oxide. This study presents the fabrication and electrical characterization of a quantum well formed by the thermal oxidation of an ultrathin silicon-on-insulator (UT-SOI) film. Structural analysis by electronic transmission reveals the formation of a monocrystalline quantum well with a homogeneous thickness and a perfectly flat surface, free from any crystalline defect. The electrical characterizations, carried out using capacitance–voltage (C–V) and current–voltage (I–V) measurements, confirm the success of the integration of the quantum well into the MOS structure. In addition, a systematic study of the dielectric properties details the evolution in bias voltage and in frequency of the main dielectric parameters of the structure such as the dielectric constant (ε*), the electrical loss (Tan δ), and the electrical modulus (M*). The results obtained demonstrate normal operation of the new structure, paving the way for efficient integration of this type of nanostructures in MOS-based photodetectors and solar cells.
Article
Full-text available
A convenient for practical use new theoretical approach describing a nonlinear frequency response of the multi-resonant nonlinear ring cavities (RC) to an intense monochromatic wave action is developed. The approach closely relates the many-valuednesses of the RC frequency response and the dispersion relation of a waveguide, from which the cavity is produced. Arising of the multistability regime in the nonlinear RC is treated. The threshold and the dynamic range of the bistability and tristability regimes for an optical ring cavity with the Kerr nonlinearity are derived and discussed.
Article
The present work focuses on experimental investigations of a bistabile silicon-on-insulator (SOI) micro-ring resonator (MRR). The resonator exploits a continuous-wave operation of the carrier-induced bistability demonstrating a stable hysteresis response at the through and drop ports when the input power exceeds the threshold value. Flipping the optical input power provides a convenient mechanism for a switching of the MRR output characteristics between two steady states having a long holding time. The transition of the resonator output between these states is experimentally investigated. It is shown that the switching speed is limited by a low-to-high transition of 188 ns. Obtained results shows an application of the passive SOI MRR as an all-optical memory cell with two complementary outputs.
Article
A silicon cross-coupled double-ring resonator system is proposed and fabricated for an optical multistability application, which consists of a racetrack resonator, a cross-coupled microring and a feedback U-shape waveguide. Transfer matrix method and rigorous simulation is used to analyze the static property. The measured device transmission spectrum can be modulated by applying a voltage to the microheater above the feedback waveguide, coinciding well with the theoretical expectation. With increase and decrease the input light power, optical multistability can be observed, which may be explained with consideration of the two-photon absorption and Kerr nonlinear effect. The presented device shows a favorable design freedom and energy consumption, which could be widely applied in optical logic gates and all-optical signal processing.
Article
The results of a study of the nonlinear frequency response of a silicon micro-ring resonator (MRR) manufacturedusing silicon-on-insulator technology are presented. Appearance of optical bistability caused by the frequencyshift of the MRR resonant spectrum under continuous wave pumping is experimentally demonstrated. The experimental results are explained in the framework of an original theory, which accounts for the linear loss,Kerr nonlinearity, two-photon absorption, free-carrier-induced absorption and dispersion, and the thermo-opticeffect. It is shown that the bistability of the frequency response originates from competition between frequencyshifts of opposite signs that appear due to the presence of the thermo-optic and free-carrier effects, with thelatter one being dominant.
Article
Recent advances in photonic integration have propelled microwave photonic technologies to new heights. The ability to interface hybrid material platforms to enhance light–matter interactions has led to the development of ultra-small and high-bandwidth electro-optic modulators, low-noise frequency synthesizers and chip signal processors with orders-of-magnitude enhanced spectral resolution. On the other hand, the maturity of high-volume semiconductor processing has finally enabled the complete integration of light sources, modulators and detectors in a single microwave photonic processor chip and has ushered the creation of a complex signal processor with multifunctionality and reconfigurability similar to electronic devices. Here, we review these recent advances and discuss the impact of these new frontiers for short- and long-term applications in communications and information processing. We also take a look at the future perspectives at the intersection of integrated microwave photonics and other fields including quantum and neuromorphic photonics.
Article
The silicon nitride (Si 3 N 4 ) planar waveguide platform has enabled a broad class of low-loss planar-integrated devices and chip-scale solutions that benefit from transparency over a wide wavelength range (400-2350 nm) and fabrication using wafer-scale processes. As a complimentary platform to silicon-on-insulator (SOI) and III-V photonics, Si 3 N 4 waveguide technology opens up a new generation of system-on-chip applications not achievable with the other platforms alone. The availability of low-loss waveguides (<;1 dB/m) that can handle high optical power can be engineered for linear and nonlinear optical functions, and that support a variety of passive and active building blocks opens new avenues for system-on-chip implementations. As signal bandwidth and data rates continue to increase, the optical circuit functions and complexity made possible with Si 3 N 4 has expanded the practical application of optical signal processing functions that can reduce energy consumption, size and cost over today's digital electronic solutions. Researchers have been able to push the performance photonic-integrated components beyond other integrated platforms, including ultrahigh Q resonators, optical filters, highly coherent lasers, optical signal processing circuits, nonlinear optical devices, frequency comb generators, and biophotonic system-on-chip. This review paper covers the history of low-loss Si 3 N 4 waveguide technology and a survey of worldwide research in a variety of device and applications as well as the status of Si 3 N 4 foundries.
Article
This paper presents the architecture of a compact, robust, and broadly tunable RF receiver based on photonic direct conversion and digital feed-forward lasers noise cancellation. In the proposed solution, the incoming RF signal is filtered and down-converted to baseband by means of an optical direct conversion (i.e., I/Q) receiving scheme (named here as signal receiver) fed by two free-running semiconductor lasers. At the same time, the beat noise of the free-running lasers is acquired by a second down-converter (reference sensor) fed by the same lasers. Then, the noise information is used by the digital feed-forward noise cancelling algorithm to enhance the frequency resolution provided by the signal receiver. The proposed strategy avoids complex lasers feedback-locking mechanisms, such as electrical/optical phased-locked loop or optical injection locking, as well as bulky RF components such as filters banks and synthesizers. An experimental validation shows an RF input range of 0 - 40 GHz, instantaneous bandwidth of 2 GHz, carrier noise of ~ -120 dBc/Hz (@ 4 kHz), out-of-band rejection > 80 dB, and tuning response < 10 μs. Implementing the scheme through integrated photonics technologies should enable increased environmental stability and a chip-scale form factor.
Article
An innovative and effective photonics-based radio frequency (RF) spectrum scanner is presented and demonstrated, enabling the detection in the 0.5-28.5 GHz range. The proposed receiver scans the whole frequency range at discrete steps, down-converting at baseband single portions of the detected spectrum, where they can be precisely acquired, without using RF bandpass filters nor optical filters. The wideband scansion is achieved by simply tuning an optical carrier only, avoiding the use of an RF synthesizer or of multiple parallel local oscillators. In more detail, the optical carrier is modulated by the detected RF signal through an electro-optical modulator, and photomixed with an optical local oscillator to down-convert the modulation sideband to baseband. The optical carrier also feeds an optical frequency comb generator-driven by a fixed RF oscillator at 1 GHz-whose output injects the local oscillator. This way, the optical carrier and oscillator are phase locked and can be tuned at steps of 1 GHz. The developed demonstrator achieves an input range up to 28.5 GHz, and a simulative analysis suggests the capability of exceeding the 0.5-40 GHz range employing commercially available devices. Moreover, it shows a linear dynamic range of 160 dB/Hz and a spuriousfree dynamic range of 109 dB/Hz 2/3 , aligned with the state-of-the-art broadband RF receivers. The proposed solution appears to fulfill the performance requirements of the demanding electronic support measures applications, with the potentials for largely reducing the receiver size.