Periodic waveguide structures for on-chip modulation and sensing

Abstract

In this paper, we summarize the recent progress on silicon photonics modulators and sensors with an emphasize on the innovation in waveguide structure. We will introduce two types of waveguide, one-dimensional (1D) slot photonic crystal waveguide (SPCW) and subwavelength grating (SWG) waveguide. The simple geometry of 1D SPCW makes it more robust to fabrication imperfections and helps reduce its propagation loss, while still maintaining the benefit of slow light. The effective electro-optic (EO) coefficient increases to 490 pm/V. The electromagnetic (EM) wave sensor developed based on this waveguide shows a sensitivity of 1.8 V/m at 14.1 GHz, which is the most sensitive EM wave sensor that has been reported. The SWG waveguide ring resonator has a bulk sensitivity more than 400 nm/RIU, which is much higher than its strip waveguide counterpart. Furthermore, its surface sensitivity is relatively independent of the thickness of analytes accumulated on its surface. These features make it an appealing sensing platform. © 2018 The Japan Society of Applied Physics 2. One-dimensional slot photonic crystal waveguide 2.1 One-dimensional slot photonic crystal waveguide structure The photon-matter interaction in space domain can be quantified by mode-volume overlap, which is defined as the percentage of optical energy existing in materials or analytes of interest. To increase the mode volume overlap, slot

Design of an On-Chip Plasmonic Modulator Based on Hybrid Orthogonal Junctions Using Vanadium Dioxide

“…In the fabrication of the device, there is a need to understand the impact of the width of the plasmonic slot (w) on the device performance, as well as the angle separating the electrodes from the waveguides (θ) given these constitute the critical dimensions of the device and are most susceptible to slight variations given the limitations of the current nanofabrication technology [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. We thus study the impact of increasing the width of the plasmonic slot (w) on the attenuation in both phases and the modulation depth.…”

Electro‐optic modulator based on vanadium dioxide epsilon‐near‐zero nanorods embedded in silicon slot waveguide

“…[9] Recently, there has been a large interest in the design of modulators based on plasmonic metamaterials due to their strong exhibition of nonlinear effects as well as high speed operation. [18][19][20][21] Hyperbolic metamaterials have been shown to drive high-speed and low-energy modulators due to their strong non-linear response and high sensitivity to changes in refractive indices. These nonlinear effects are particularly enhanced in the epsilon-near-zero regime where a component of the real part of the effective permittivity tensor of the metamaterial is near zero (Re(𝜖)∼0).…”

“…The operation of the metamaterial in this regime is dependent on its geometry and can be tuned to achieve superior performance at a chosen wavelength. [18][19][20][21][22] In this paper, we design and optimize an electro-optic modulator using electrically switchable VO 2 nanorods embedded in a silicon waveguide to form a metamaterial operating in the epsilon-near-zero regime. We take advantage of the large refractive index contrast between VO 2 in the metallic and insulator phases and epsilon-near-zero regime to increase the modulation index and reduce losses.…”

Mid-Infrared, Ultra-Broadband, Low-Loss, Compact Arbitrary Power Splitter Based on Adiabatic Mode Evolution

“…Silicon photonics stands to be a highly desirable platform for the scalable implementation of photonic applications due it its fabrication compatibility with mature CMOS technologies [1 ], [ 2], and thus enabling low cost manufacturing of Photonic Integrated Circuits (PIC) at high volume. Interest in Mid-Infrared (MIR) Photonics has been gaining momentum in both academia and industry.…”