Multiwavelength diffraction and apodization using binary superimposed gratings

Author

Avrutsky, Ivan A. ; Fay, Martin ; Xu, J.M.

Author_Institution

Dept. of Electr. & Comput. Eng., Toronto Univ., Ont., Canada

Volume

10

Issue

6

fYear

1998

fDate

6/1/1998 12:00:00 AM

Firstpage

839

Lastpage

841

Abstract

The binary superimposed grating (BSG), consisting of equal-size segments of two possible values of refractive index and capable of effecting multiwavelength reflection, offers ease of fabrication and great versatility in guided-wave wavelength-division-multiplexing (WDM) applications. We present an analytical formula for the coupling strength of a BSG as a function of segment size, and verify it with numerical transfer matrix simulations of the grating reflectance spectra. Perfect agreement is found for a single grating, and values /spl sim/10%-12% less than predicted for 2-11 superimposed gratings. Subdividing the grating into sections of grouped segments permits step-like apodization, while maintaining binary index and base segment size. Sidemode suppression ratios (SMSRs) of 27 and 16 dB are computed for single-peak and 11-peak BSGs respectively.

Keywords

diffraction gratings; optical communication equipment; optical images; reflectivity; wavelength division multiplexing; apodization; binary index; binary superimposed gratings; coupling strength; equal-size segments; grating reflectance spectra; grouped segments; guided-wave WDM applications; multiwavelength diffraction; multiwavelength reflection; numerical transfer matrix simulations; refractive index; segment size; sidemode suppression ratios; step-like apodization; superimposed gratings; Bragg gratings; Diffraction gratings; Distributed Bragg reflectors; Etching; Fabrication; Holography; Laser tuning; Refractive index; Resonance; Wavelength division multiplexing;

fLanguage

English

Journal_Title

Photonics Technology Letters, IEEE

Publisher

ieee

ISSN

1041-1135

Type

jour

DOI

10.1109/68.681503

Filename

681503