Grating-assisted co-directional vertical coupler optical filter having well-suppressed sidelobe characteristics and method of fabricating the same

摘要

The present invention relates to an optical filter whose a sidelobe disturbing a characteristic of an optical filter by weighting an optical coupling efficiency between waveguides is controlled upon applying a selective area growth method in a wavelength selective variable semiconductor optical filter and method of fabricating the same. The present invention can control the thickness of growth layer selectively by controlling the width of the dielectric thin film mask whose the growth is not achieved in the selective area growth method, can control the distance between two waveguides of the wavelength selective variable semiconductor optical filter by applying the result on the distance control between two waveguides. Accordingly, there can be changed an optical coupling efficiency between two waveguides spatially. Because the sidelobe characteristics is largely improved if the distance between two waveguides is controlled temporarily to be corresponded to one period of Hamming function, there can be fabricated a semiconductor optical filter whose the characteristic is very excellent when applying the present invention.