Optical modulators with high modulating efficiency and nanoscale size are essential components of photonic communication networks. In recent years, optical modulators based on phase-change materials have considerable application prospects. However, it is still challenging to solve the problem that the footprint and modulation performance of modulators cannot be taken into account at the same time. To this end, we propose an ultra-compact right-angle curved waveguide optical modulator design based on vanadium dioxide (VO2), which consists of a high-loss right-angle curved waveguide and a rectangular VO2 embedded in its bend. Since VO2 has two stable phases of metal phase and semiconductor phase, there is a difference in its optical performance: when VO2 is in the semiconductor phase, its light transmission is low due to the high bending loss of the right-angle bending waveguide; When VO2 is in the metal phase, a mirror-like structure is formed at the bending of the right-angle waveguide, which significantly increases the output of the right-angle curved waveguide. The optical modulator with a footprint of 0.6μm×0.6μm has an extinction ratio of 8.6 dB operating at a wavelength of 1550 nm in transverse electric (TE) mode. Our design can achieve a high extinction ratio with high efficiency in an extremely small footprint, with great potential in constructing on-chip fast all-optical communication networks.
With increasing demands in all-optical signal processing functions such as switching and modulating in integrated photonic-electronic circuits, plasmonic modulators are getting lots of attentions. In this paper, we present a novel design of hybrid plasmonic modulator based on insulator-metal phase transition in vanadium dioxide (VO2). The device consists of two silicon tapers and a metal-VO2-insulator-silicon hybrid plasmonic structure that are inserted into a strip silicon waveguide, with 120 nm x 800 nm modulating section within 450 nm x 2 μm device footprint. By taking advantages of the large refractive index contrast between the metal and semiconductor phase of VO2, the proposed modulator achieves a high modulation depth of 14.852 dB with a low insertion loss of 1.804 dB. Moreover, we have systematically analyzed the geometry dependence of the device and the influence of broadband light on modulation performances. Considering the effects of seed layer in VO2 deposition process, we have also studied the modulating performances using different dielectric layers. Our design can be practically fabricated, and a complete process flow is provided. We believe this work has great values in promoting the industrial process of silicon photonics in the fields of optical communication and data storage.
A unique design method of two cascaded diffractive optical elements (DOEs) with different sizes of effective phase region to modulate broadband beam is presented with consideration of single production material and low relief height on DOE. The iterative algorithm to calculate the relief heights on these DOEs is introduced at first. Where after, a broadband beam at wavelength from 500nm to 600nm propagates through the designed DOEs and is focused on the target plane in the simulation part. The shaping results demonstrate the excellent shaping ability of this unique design method. The shaping system proposed in this paper is significant for nonmonochromatic light modulation and has many applications such as graphic encryption, three-dimensional color display and multi wavelength division multiplexing.
Photolithography has been one of the most important technologies in modern society, especially in semiconductor industry. However, due to the limitation of optical diffraction, this technique becomes more and more complex and expensive. In this paper, we experimentally study two promising techniques, near-field scanning optical lithography and nanoimprint lithography, which both have been proved to be alternatives to photolithography, and achieve sub-wavelength resolution. Taking advantage of bowtie apertures, near-field scanning optical lithography can achieve high resolution beyond the Rayleigh diffractive limit. Here, we report a novel method to fabricate bowtie aperture with sub-15 nm gap, producing highly confined electric near-field by localized surface plasmon (LSP) excitation and nanofocusing of the closely tapered gap, and obtain lithography results with 21 nm resolution (FWHM).We also develop a new plate-to-roll nanoimprint lithography (P2RNIL). Compared with plate-to-plate nanoimprint lithography (P2PNIL) and roll-to-plate nanoimprint lithography (R2PNIL), it avoids cylinder template fabrication in P2RNIL and significantly improves the productivity in P2PNIL. Our P2RNIL system can realize large-area nanoimprint continuously with high resolution and high speed.
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.