An Optical Leaky Wave Antenna by a Waffled Structure

This paper presents an optical leaky waveguide antenna, i.e., waffled waveguide (WWG). From both simulations and experiments, we evaluate the effectiveness of the WWG in terms of the antenna characteristics. The WWG radiates a narrow beam tilted by sweeping the incident wavelength, and consists of an array of small rectangular holes fabricated by silicon photonics. Compared to the conventional grating waveguide designed only with the longitudinal period and depth as free parameters, the lateral period of the rectangular holes in the WWG adds the design flexibility; consequently, the WWG achieves a large aperture size and high antenna gain. We reconstruct radiation pattern from aperture distribution and confirm the high antenna gain experimentally.