Ultra-Low Index-Contrast Polymeric Photonic Crystal Nanobeam Electro-Optic Modulator

Abstract

A novel nanocavity-based polymer-on-insulator (POI) electro-optic modulator (EOM) is proposed. It consists of a polymeric photonic-crystal nanobeam cavity (PCNC) with ultra-low index-contrast (n cavity /n bg = 1.17). Based on three-dimensional (3D) finitedifference time-domain (FDTD) method, the PCNC design and optimization are investigated theoretically. A high quality-factor (Q) of 3.4 × 10 4 and small mode-volume of 22.8 (λ/n SE O ) 3 can be achieved. In order to judge the efficiency of the cavity design for electro-optic (EO) modulation, the optical modes and the electric field distribution are computed using an electromagnetic finite-element solver. Benefiting from the fast and strong EO effect in polymers, the modulator shows an EO modulation efficiency of up to 16 pm/V, which is over an order of magnitude higher than that in lithium niobate (LN) PCNCs. Moreover, the device is only 80 μm in length, leading to a voltage-length product V π × L = 0.05 V•cm, which is much smaller than those of Mach-Zehnder modulators. To the best of our knowledge, this is the first on-chip POI-based EOM that features both ultra-compact size and high modulation efficiency. Hence, it is potentially an ideal platform for applications in optical communications, electric-field sensing, and tunable photonic circuits.

Design of Ultracompact High‐Speed‐Integrated Lithium–Niobate Periodic Dielectric Waveguide Modulator

“…[3][4][5][6] As a novel design of modulators, photonic crystal modulators have been attracting significant interest. [26][27][28][29][30][31][32][33][34][35][36][37] Most of these modulators are based on MZI or resonators. Brosi et al demonstrated an MZI silicon-polymer hybrid modulator with each arm consisting of a slotted photonic crystal waveguide filled with polymer.…”