Open AccessTransmission Characteristics of Tuneable Optical Filters Using Optical Ring Resonator with PCF Resonance Loop
Author(s) -
Kazhal Shalmashi,
Faramarz E. Seraji,
Mansur Rezaei Mersagh
Publication year - 2011
Publication title -
optics and photonics journal
Language(s) - English
Resource type - Journals
eISSN - 2160-889X
pISSN - 2160-8881
DOI - 10.4236/opj.2011.14028
Subject(s) - resonator , optics , coupling coefficient of resonators , full width at half maximum , materials science , optical filter , filter (signal processing) , modulation (music) , physics , acoustics , computer science , computer vision
A theoretical analysis of a tuneable optical filter is presented by proposing an optical ring resonator (ORR) using photonic crystal fiber (PCF) as the resonance loop. The influences of the characteristic parameters of the PCF on the filter response have been analyzed under steady-state condition of the ORR. It is shown that the tuneability of the filter is mainly achieved by changing the modulation frequency of the light signal applied to the resonator. The analyses have shown that the sharpness and the depth of the filter response are controlled by parameters such as amplitude modulation index of applied field, the coupling coefficient of the ORR, and hole-spacing and air-filling ratio of the PCF, respectively. When transmission coefficient of the loop approaches the coupling coefficient, the filter response enhances sharply with PCF parameters. The depth and the full-width half-maximum (FWHM) of the response strongly depends on the number of field circulations in the resonator loop. With the proposed tuneability scheme for optical filter, we achieved an FWHM of ~1.55 nm. The obtained results may be utilized in designing optical add/drop filters used in WDM communication systems