Ferroelectric Sr0.6Ba0.4Nb2O6 thin film based broadband waveguide coupled surface plasmon electro-optic modulator

Present article demonstrates the enhanced dynamically tuneable EO modulation characteristics in ferroelectric Strontium Barium Niobate (SBN, Sr0.6Ba0.4Nb2O6) thin film modulator based on waveguide coupled surface plasmon resonance. The alternating modulating signals having broad frequency range (1 kHz to 10 MHz) with varying amplitude (40 kV/cm to 400 kV/cm) was applied to estimate the resonance frequency (similar to 1 MHz) using differential modulated intensity interrogation signal. A high value of EO coefficient r = 310 pm/V leading to Modulation index of 56% was achieved with sensitivity of about 0.33 at resonance possessing a characteristics length of 54.64 mu m. These waveguide modes coupled with the plasmon modes paves a way for development of EO modulators utilizing materials with high losses. Therefore, a thin film based WCSPR-EO modulator with compact footprint, low operation voltage, broad operation spectrum and faster speed of modulation was fabricated which paves the way for on-chip optical communications.