Wavelength-selective photodetector with integrated vertical taper structure

We have fabricated the novel wavelength-selective photodetector with vertical taper structure. In this structure, wide tunable range, narrow spectral linewidth and high speed-response can be achieved simultaneously. The vertical taper, the key part in the whole integrated structure, was fabricated on Al_0.3Ga_0.7As epitaxial layer with inclined angle of 1.32° by dynamic mask etching technique. A spectral linewidth of 0.8 nm (FWHM) and a quantum efficiency of 75.17% have been achieved experimentally, with an absorption layer thickness of only 0.119 μm. If we replaced the GaAs with InGaNAs as the absorption material, the spectral response of such a photodetector would easily extend to the long wavelength region.