Silicon modulators, which play a crucial role in silicon photonics systems, are currently trending towards lower biases and improved bandwidth. The plasma dispersion effect of silicon modulators highlights the importance of carrier concentration in improving performance. Common doping profiles have been optimized for high efficiency but may suffer from increased loss. Our horizontal S-shaped modulator improves silicon modulators with excellent VπL of 0.77 V·cm and low loss of 10.9 dB/cm, with small resistance and capacitance enhancing bandwidth over 27 GHz. This design is suitable for high-speed and low-voltage applications with benefits of saving power.
Silicon modulators play an important role in silicon photonics for efficient modulation and transmission of optical signals. Enhancing the performance of silicon modulators has largely relied on optimizing doping profiles. However, in recent years, progress in finding superior solutions to optimize performance has faced obstacles. To address this challenge, the concept of inverse design, which has gained popularity in passive photonic devices, can be applied to silicon active devices by dividing the doping region into segments and adjusting each segment based on feedback from the results. Consequently, we introduce the inverse design method into modulator doping profile optimization by utilizing the particle swarm optimization (PSO) algorithm, resulting in the attainment of a G-shaped doping profile for the modulator. The proposed modulator demonstrates the superior VπL of 0.48 V·cm and the low loss of 13.5 dB/cm. The small-signal frequency response suggests a reliable operation range under reverse biases of 1 V to approximately 3 V with the bandwidth over 26 GHz. The G-shaped silicon modulator exhibits impressive modulation efficiency and minimal loss, indicating its high potential for use in microwave front-end applications. The utilization of inverse design holds immense promise in advancing active silicon photonic devices for faster, higher-capacity and more reliable data communication systems.
KEYWORDS: Modulation, Doping, Silicon, Design and modelling, Capacitance, Resistance, Waveguides, Silicon photonics, Data communications, Monte Carlo methods
In order to achieve effective modulation, researchers have studied various doping profiles within silicon modulators, but optimization has so far mainly been carried out in the cross-section or solely in the propagation direction. Generating 3D doping profile can add more optimizing dimensions to the modulator design. This work proposes a modulator based on U-shaped and L-shaped junctions by the 3D effective Monte-Carlo method. The simulation results show that the modulation efficiency is 0.67 V·cm, and the loss is 25.7 dB/cm, with the bandwidth more than 36.3 GHz. This work demonstrates the benefits of 3D modulator design as the direction of light propagation is utilized to transport carriers, and provides a modulator solution for high-speed datacom.
As a widely studied fundamental block in photonic integrated circuits, multimode interferometer (MMI) is excellent in coupling of multiple light sources with equal intensity. However, unacceptable excess loss occurs if phase-matching is not satisfied at any input port. In this paper, we proceed direct binary search (DBS) algorithm to optimize an inverse designed 3 × 1 MMI coupler with nano-pixel structure and realize high-efficiency coupling of equal input (intensity and phase) sources of 1550 nm fundamental TE mode, with a compact footprint of 2.5 × 2.5 μm2 and low excess loss of 0.04dB. We also investigated the possibility of inverse design method to handle the coupling of multiple input sources with arbitrary phase difference among different ports.
Interleaved modulators enable more optimized doping profiles for higher modulation efficiency and lower loss. Nevertheless, as far as we know, complex doping for interleaved modulators has hardly been studied. Hence this work proposes a modulator based on interleaved vertical and U-shaped junctions using the Monte-Carlo simulation. The results illustrate that the modulation efficiency of the designed interleaved period is 0.57 V·cm, while the loss is 15.5 dB/cm. This high-efficiency design verifies the benefits of interleaved 3D modulator design as significantly increasing modulation efficiency with low loss, showing great potential for high-speed application.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.