Enhanced transmission through photonic-crystal-based bent waveguides by bend engineering

Abstract

We have studied the transmission of light through two-dimensional photonic-crystal-based waveguides with two 60° bends. The waveguides consist of three or five missing rows of holes inside a triangular photonic crystal block fabricated on an AlGaAs/GaAs waveguide structure. Fine tuning of the bend design results in a severe impact on the transmission behavior, leading to losses as low as 1.1 dB/bend. Measurements of losses in the bends were performed by a comparison with a straight guide of identical length.

Systematic design of photonic crystal structures using topology optimization: Low-loss waveguide bends

“…Waveguides with dielectric columns in a rectangular configuration have been subjected to extensive computations 3 and recently waveguides with holes etched in a triangular pattern in a dielectric have been analyzed thoroughly both theoretically and experimentally. 4 Despite the considerable amount of studies on PC waveguides that have appeared, few papers have dealt with optimization or the inverse problem of obtaining structures with optimal or desired properties. The few papers that have appeared ͑e.g., Refs.…”

Wide bandwidth directional beaming via waveguide ports in photonic crystals

“…Some special structures can be further added to the present structure in order to enhance the efficiency of the beam bending [24], beam splitting [25] and coupling of the output ports to free space [26]. Although a dielectric rod type PC is adopted here to demonstrate the performance of our design, the principle of our design can also work well for air hole type PCs.…”

Glass nanofibers for micro- and nano-scale photonic devices

“…The measured bending loss of a 5-lm-radius bend assembled with a 550-nm-diameter glass nanofiber is typically less than 1 dB at 633-nm wavelength, which is small enough for microphotonic circuits. By comparison, bending waveguides based on planar photonic crystal structures not only require multiple periods (which increase the overall size) and sophisticated fabrication techniques [23][24][25], but they also have inevitable out-of-plane loss. In contrast, aerogel-supported nanofiber bends offer the advantages of compact overall size, low loss, simple structure and easy fabrication [26].…”