Research Progress of High-resolution Arrayed Waveguide Spectroscopy

In recent years, astronomical observation has put forward higher requirements for observation environment, resolution power and simultaneous observation quantity, which makes the cost of traditional spectrometer spiraling. The development of integrated photonics provides a miniaturized, low-cost and environment-friendly solution for astronomical spectral observation. However, high resolution spectrum is hard to achieve because of the highly repetitive structure and defocus aberration existing in re-imaging system when needing cross dispersion. Based on Silica-on-Silicon material platform with a refractive index contrast of 0.23%, new structure of cascaded modulation arrayed waveguides(CMAW) with total length difference of 22mm are arranged in a square chip with a side length of 40mm, having a theoretical resolution of 20,000@1550nm and tested resolution of 15,000@1550nm. Our work demonstrates the potential of integrated photonics applying in high resolution astronomical spectral observation, three times above the record of available resolution power international, which is expected to provide a solution for space observation and large-scale spectral survey.