Symmetric Meandering Distributed Feedback Structures for Silicon Photonic Circuits

Abstract

Fano lineshapes and electro-magnetically induced transparency-like peaks in the transmittance of a transverse electric polarization silicon-on-insulator symmetric meandering distributed feedback photonic structure are demonstrated. The coupling constants at the five identical directional couplers are varied to obtain the desired spectral responses. The numerically simulated and experimentally measured transmittance spectra are in good agreement with each other. The numerically calculated and experimentally measured insertion loss for the symmetric meandering distributed feedback structure with directional coupler coupling length Lc = 10 μm are respectively -5 dB and -17 dB, including the grating couplers. Fano lineshapes with mode splitting is observed at directional coupler coupling constant value C of 0.24. For coupling constant value of C ~ 0.78, electro-magnetically induced transparency-like peaks are observed, and spectrally adjusted by varying the directional coupler coupling length. Fano lineshapes show an extinction ratio of more than 26 dB and slope ratio of 368 dB/nm. Electro-magnetically induced transparency-like peaks show a quality-factor on the order of 5 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> . The symmetric meandering distributed feedback structure shows promise for possible applications as an optical switch, and an optical filter in wavelength division multiplexing and data networks, as well as optical sensors in optical diagnostics, using silicon photonics.