This paper illustrates the design and fabrication of wavelength filters using resonant cavity which is constructed out of a phase shifted vertical side wall grating. The resonant cavity is analyzed as a Fabry-Perot resonator and the variation in cavity quality factor (Q) and transmission with respect to various grating parameters is studied. It is observed that a high Q-factor together with a high transmittivity can be obtained for this wavelength filter through optimization in grating length and reduction in the out of plane loss. Multiple phase shifts are applied in the grating to get a coupled cavity configuration so that channel isolation and spectral shape is improved. The channel wavelengths in a DWDM ITU grid C band (100GHz spacing) is simulated by varying the phase shift length of the gratings and good channel isolation with constant Q -factor and transmittivity is observed for the spectrum. The paper also explains the effective fabrication process flow for this structure on a silicon wafer through e-beam lithography and Reactive Ion Etching (RIE).

Date Published: 15 November 2010
PDF: 10 pages
Proc. SPIE 7847, Optoelectronic Devices and Integration III, 78470H (15 November 2010); doi: 10.1117/12.869644

Published in SPIE Proceedings Vol. 7847:
Optoelectronic Devices and Integration III
Xuping Zhang; Hai Ming; Alan Xiaolong Wang, Editor(s)