||In order to achieve the integration of photonic circuit, the spatial selectivity of bandgap tuning on a wafer is an important issue. In this work, a quantum well intermixing (QWI) technique by sputtering SiO2 and followed by rapid thermal annealing, called impurity free vacancy diffusion( IFVD ), was used to perform the spatially bandgap tuning on a wafer. Patterned SiO2 regions are defined as the bandgap tuning area, while in the other area (without SiO2 cap layer) the wavelength shift suppression is performed by exposing in nitrogen flow surrounding.|
Defined by photolithography, the QWI area could narrow down to the scale from 40um by 200um. By monitoring the bandgap using photoluminescence (PL) method, three different operating wavelengths of 1470nm, 1510nm, 1540nm at different regions have been achieved in a single wafer. The blue-shift of PL can reach more than 60nm within 7mins annealing. The integration of a semiconductor optical amplifier (SOA) and electroabsorption modulator (EAM) with electrical isolation region (ISO) is used to test wafer. The result showed that the amplifying wavelength of SOA is the same as the modulating wavelength of EAM, which resulting in the optimized operating efficiency of the integrated devices. The transmission of QWI device reaching -3dB, in comparison to non-QWI device with transmission of -12dB, is greatly improved. The gain of SOA is up to 35dB and the modulation of EAM is 6.68dB, which is limited by Zn diffusion. An opened and clear 40GB/s eye diagram is demonstrated, which showed under high temperature processing, the fabricated device still work. Without re-growth, just simple processing like sputtering and annealing, spatially bandgap tuning and the photonic integrated circuit are realized.