Performance of parametric spectro-temporal analyzer (PASTA)

Abstract

Parametric spectro-temporal analyzer (PASTA) is an entirely new wavelength resolving modality that focuses the spectral information on the temporal axis, enables ultrafast frame rate, and provides comparable resolution and sensitivity to the state-of-art optical spectrum analyzer (OSA). Generally, spectroscopy relies on the allocation of the spectrum onto the spatial or temporal domain, and the Czerny-Turner monochromator based conventional OSA realizes the spatial allocation by a dispersive grating, while the mechanical rotation limits its operation speed. On the other hand, the PASTA system performs the spectroscopy function by a time-lens focusing mechanism, which all-optically maps the spectral information on the temporal axis, and realizes the single-shot spectrum acquisition. Therefore, the PASTA system provides orders of magnitude improvement on the frame rate, as high as megahertz or even gigahertz in principle. In addition to the implementation of the PASTA system, in this paper, we will primarily discuss its performance, including the tradeoff between the frame rate and the wavelength range, factors that affect the wavelength resolution, the conversion efficiency, the power saturation and the polarization sensitivity. Detection bandwidth and high-order dispersion introduced limitations are also under investigation. All these analyses not only provide an overall guideline for the PASTA design, but also help future research in improving and optimizing this new spectrum resolving technology.