Transmission mechanisms for simple 90° bends in waveguides in photonic crystals consisting of a square lattice of pillars (pillar PCs) were investigated. We utilized the fact that the electromagnetic field of a guided wave is characterized by two predominant plane-wave components. It was revealed by theoretical analyses that, if kd is the wave vector of those plane-wave components, a guided wave with a Bloch wave vector k can efficiently propagate through a 90° waveguide bend when k/kd = 1/√2. Under this wave-vector condition, a single plane-wave component of a guided wave carries nearly all the electromagnetic power through the waveguide bend. Impedance matching at the waveguide bend is also established by that power-carrying plane-wave component. It was demonstrated, using three-dimensional finite-difference time-domain simulation, that a simple 90° bend of a waveguide in a pillar-PC slab efficiently transmitted a guided wave under that wave-vector condition.
|Number of pages||8|
|Journal||Journal of the Optical Society of America B: Optical Physics|
|Publication status||Published - 2005 Nov|
ASJC Scopus subject areas
- Statistical and Nonlinear Physics
- Atomic and Molecular Physics, and Optics