Abstract
CMOS-compatible nonlinear optics platforms with high Kerr nonlinearity facilitate the generation of broadband spectra based on self-phase modulation. Our ultra – silicon rich nitride (USRN) platform is designed to have a large nonlinear refractive index and low nonlinear losses at 1.55 μm for the facilitation of wideband spectral broadening. We investigate the ultrafast spectral characteristics of USRN waveguides with 1-mm-length, which have high nonlinear parameters (γ ∼ 550 W−1/m) and anomalous dispersion at 1.55 μm wavelength of input light. USRN add-drop ring resonators broaden output spectra by a factor of 2 compared with the bandwidth of input fs laser with the highest quality factors of 11000 and 15000. Two – fold self phase modulation induced spectral broadening is observed using waveguides only 430 μm in length, whereas a quadrupling of the output bandwidth is observed with USRN waveguides with a 1-mm-length. A broadening factor of around 3 per 1 mm length is achieved in the USRN waveguides, a value which is comparatively larger than many other CMOS-compatible platforms.
Highlights
The development of complementary metal-oxide semiconductor (CMOS)-compatible platforms for nonlinear optics offers tremendous benefits to ultrafast all-optical signal processing and light generation[1]
Silicon nitride (Si3N4)[14,15,16,17,18] and Hydex glass are two nonlinear optic platforms which have been used with much success to efficiently reduce nonlinear loss as well as linear loss
We study ultra – silicon rich nitride (USRN) waveguides for their ability to acquire nonlinear phase using ultra – short lengths
Summary
The development of complementary metal-oxide semiconductor (CMOS)-compatible platforms for nonlinear optics offers tremendous benefits to ultrafast all-optical signal processing and light generation[1]. Chalcogenide glasses[7,8,9,10] and AlGaAs11–13 are promising platforms possessing high third-order nonlinearities, broadband transparency and low TPA, though limited to applications where CMOS compatibility is not required due to the challenging fabrication for highly efficient waveguides In this way, CMOS-compatible devices based on these materials are in development. The USRN material[25,26] is distinguished from the typical silicon rich nitride platform as it is characterized by a much larger linear refractive index (n = 3.1), much larger nonlinear parameters (∼550 W−1/m vs a few W−1/m) though both have a sufficiently large band gap to eliminate TPA at the 1.55 μm wavelength. The short waveguides with a 1-mm-length scale are sufficiently short to be well below the dispersion length and nonlinear dynamics are predominantly governed by the waveguide’s nonlinearity
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