Title :
An analytic method for designing passband flattened DWDM demultiplexers using spatial phase modulation
Author :
Shi, Zhimin ; He, Jian-Jun ; He, Sailing
Author_Institution :
Centre for Opt. & Electromagn. Res., Joint Lab. of Opt. Commun. of Zhejiang Univ., Hangzhou, China
Abstract :
An analytic method of spatial phase modulation based on Fourier analysis is introduced for the design of a planar waveguide demultiplexer with a flat-top spectral response. An analytic formula for an etched diffraction grating demultiplexer is derived using the scalar diffraction theory. The spatial phase modulation is realized by slightly adjusting each grating facet´s position according to the analytic formula to obtain a spectral response with a flat top and sharp transitions as well as a good dispersion characteristic. The analytic formula is characterized by two parameters: a transverse shift distance and a profile exponent for the phase modulation. A linear relation between the passband width and the transverse shift distance is given, and an optimal figure of merit of the spectral response is obtained by choosing an appropriate profile exponent. A numerical example of a typical SiO2 etched diffraction grating demultiplexer is used to demonstrate the advantages of this method.
Keywords :
demultiplexing equipment; diffraction gratings; optical communication equipment; optical design techniques; optical modulation; optical planar waveguides; optical waveguide theory; phase modulation; wavelength division multiplexing; Fourier analysis; SiO2; SiO2 etched diffraction grating demultiplexer; etched diffraction grating demultiplexer; flat-top spectral response; good dispersion characteristic; grating facet position; optimal figure of merit; passband flattened DWDM demultiplexer design; phase modulation; planar waveguide demultiplexer; scalar diffraction theory; spatial phase modulation; spectral response; transverse shift distance; Arrayed waveguide gratings; Design methodology; Diffraction gratings; Electromagnetic waveguides; Etching; Optical waveguides; Passband; Phase modulation; Planar waveguides; Wavelength division multiplexing;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2003.817696
