Polyimides and polyimide-silica hybrid AWG device with 2.2% and 1.6% refractive index difference (□), and the transmission spectrum of AWG's device indicated the insertion loss were -3.12 dB and -3.16 dB, crosstalk were -20 dB and -15 dB, and side-lobe were both lower than -60 dB, respectively, by 2D beam propagation method were investigated in this study. The smallest chip size of the whole device is smaller than 3.4 cm x 1.8 cm, and the highest coupling loss of the rib waveguide for single mode fiber was about -1.02 dB. Based on the 3D simulation results, the devices will be really fabricated by thin-film deposition, photolithography and dry-etching processes.
Optical measurements of polyimides and polyimide-silica hybrid materials formed on quartz glass indicated, the refractive indexes of top cladding/core/bottom cladding layers at 1550 nm wavelength were 1.522/1.546/1.522 and 1.4907/1.53/1.4907, respectively. The extinction coefficients of all samples indicated approximately zero at 1550 nm wavelength. We will adopt these polyimides and polyimide-silica hybrid materials to perform real AWG fabrication. From atomic force microscopy (AFM) analysis of polyimides and polyimide-silica hybrid materials revealed, the surface average roughness was 0.236 nm and 0.364 nm, respectively. The structures of polyimides and polyimide-silica hybrid materials were identified by fourier transform infar ray (FTIR). High-resolution transmission electron microscopy (HRTEM/EDAX) was used to study the localized interface structure and compositional distribution. The morphology of rib structure waveguides, polyimides and polyimide-silica hybrid films were examined by scanning electron microscopy (SEM).