512-channel SiN-based AWG-spectrometer for OCT on a chip

We present design, technological verification, and optimization of a compact 512-channel silicon nitride-based AWG-spectrometer developed for the realization of an on-chip spectral domain optical coherence tomography system. The spectrometer was designed for TM-polarized light with a central wavelength of 850 nm and having a resolution of 0.1 nm. For the design the AWG-Parameters tool was used. Simulations were performed using Optiwave’s PHASAR photonics tool and the designed structure was fabricated in a standard CMOS foundry process. The simulated and measured optical spectra were evaluated and used to further optimize the AWG structure. The AWG-spectrometer was integrated onto the chip and the OCT measurements proved its suitability for OCT on chip applications.