Pure Temporal Dispersion for Aberration Free Ultrafast Time-Stretch Applications

Photonic time-stretch applications overcome the speed limitations of conventional digitizers and enable the observation of nonrepetitive and statistically rare phenomena that occur on short timescales. In most time-stretch applications, large temporal dispersion with large bandwidth is highly desired to satisfy the far-field diffraction regime. However, most conventional spatial dispersers or chirped fiber Bragg gratings are constrained by their spatial volume, which can be overcome by using ultra-low-loss dispersive fibers, an ideal medium for large temporal dispersion (beta(2)), but they suffer from third-order dispersion (beta(3)) and aberrations. In this paper, an optical phase conjugation-based, third-order dispersion compensation scheme was introduced, with accumulated beta(2) and eliminated beta(3), and it achieved a +/- 3400-ps(2) pure temporal dispersion of over 30-nm bandwidth. Leveraging this pure temporal dispersion, up to 2% of temporal aberrations were eliminated. Furthermore, Fourier domain spectroscopy achieved a record 15000 optical effective resolvable points, with a nondegraded 2-pm resolution over a 30-nm range.

Automated summary

This paper introduces an optical phase conjugation-based scheme to compensate for third-order dispersion, achieving large temporal dispersion and high-resolution optical imaging. Leveraging pure temporal dispersion, it eliminates temporal aberrations and achieves a record number of optical resolvable points with nondegraded resolution over a wide bandwidth.