[OPTICAL REVIEW Vol. 6, No. 2 (1999) 131-138]
Spectral Analysis of Transmission Echelon Grating Filters for Photonic Networks
NTT Opto-electronics Laboratories, 9-11, Midori-cho 3-chome, Musashino, Tokyo, 180-8585 Japan
(Received July 6, 1998; Accepted November 27, 1998)
This paper describes a method of analyzing spectral behavior that allows transmission echelon grating filters to be designed for use in constructing photonic networks. These networks include dense wavelength division multiplexing systems and other such applications. First, the configuration and principle of this filter are described. Then, the transmittance spectrum of the transmission echelon grating filter is considered for incident lights with rectangular, Gaussian, and sinc electric field distributions. Next, a more realistic spectral response is considered by taking reasonable fabrication errors into account. Finally, the group delay and the transmittance of linearly chirped echelon grating filters are analyzed to access their potential for use as a wavelength dispersion equalizer. These analytical results make it possible to design practical echelon grating filters.
Key words : echelon grating, bandpass filter, spectral analysis, complex electric field, chirped grating, delay time response, dispersion equalizer