[OPTICAL REVIEW Vol. 6, No. 6 (1999) 489-493]
Fabrication and Performance of 1.55 μm Transmission Glass-Echelon Grating Filters
NTT Telecommunications Energy Laboratories, 9-11, Midori-cho, 3-chome, Musashino, Tokyo, 180-8585 Japan
(Received April 17, 1999; Accepted July 16, 1999)
This paper describes the fabrication method and the measured spectral behavior of a 1.55 μm transmission glass-echelon grating filter. This echelon grating consists of a pile of identical plane-parallel glass plates constructed using a special assembling tool. The experimental result confirmed the accuracy of the Fourier transform which indicated that the spectral passband width was inversely proportional to the beam size. This feature makes it possible to use the filter as a bandpass filter or a comb filter when constructing photonic networks. The echelon filter has certain intrinsic advantages including a low insertion loss and polarization independence. Moreover, it offers good cost performance and excellent design flexibility.
Key words : echelon grating, bandpass filter, transmittance spectrum, beam size, Gaussian light field, photonic network, Fourier series