While sinogram-based methods have the advantage of eliminating beam hardening effects, results of this study suggest improvements in the accuracy and reliability of extracting tissue parameters by applying the DECT stoichiometric calibration of Bourqueet al. to monoenergetic images being generated with such DECT reconstruction methods.

Low propagation loss GeSbS waveguides (0.56 dB/cm) are fabricated in a wafer scale process. Simulation of a 2 cm long, 1.2 μm wide waveguide with 100 ps/nm/km peak dispersion predicts coherent supercontinuum generation at 1.55 μm pump wavelength. Octave-spanning supercontinuum using a dispersive wave is experimentally demonstrated using picojoule-level energy (26 pJ, 240 fs pulse width, 77 W peak power) pulses.

The cascaded integration of optical waveguides with third-order optical nonlinearity (χ (3) susceptibilitiy) with lithium niobate (LiNbO 3 ) waveguides is demonstrated on the same chip. Thin-film (LiNbO 3 ) and chalcogenide (ChG) glass (Ge 23 Sb 7 S 70 ) waveguides are integrated on silicon (Si) substrates. An optical mode transition between the two waveguides is achieved through low-loss mode-converting tapers, with a measured loss of ∼1.5 dB for transverse-electric and ∼1.75 dB for transverse-magnetic input polarizations. For nonlinear characterization, wavelength conversion via four-wave mixing is demonstrated on the ChG-LN waveguides. This platform provides an efficient method for the utilization of secondand third-order optical nonlinearities on the same chip, rendering it ideal for nonlinear applications such as stabilized octave-spanning optical frequency comb generation.

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Miniaturization of frequency-comb sources could open a host of potential applications in spectroscopy, biomedical monitoring, astronomy, microwave signal generation, and distribution of precise time or frequency across networks. This review article places emphasis on an architecture with a semiconductor mode-locked laser at the heart of the system and subsequent supercontinuum generation and carrier-envelope offset detection and stabilization in nonlinear integrated optics.