Heterogeneous integration of Si photodiodes on silicon nitride for near-visible light detection.

Silicon nitride (SiN) is used extensively to complement the standard silicon photonics portfolio. However, thus far demonstrated light sources and detectors on SiN have predominantly focused on telecommunication wavelengths. Yet, to unlock the full potential of SiN, integrated photodetectors for wavelengths below 850 nm are essential to serve applications such as biosensing, imaging, and quantum photonics. Here, we report the first, to the best of our knowledge, microtransfer printed Si p-i-n photodiodes on a commercially available SiN platform to target wavelengths <850 nm. A novel heterogeneous integration process flow was developed to offer a high microtransfer printing yield. Moreover, these devices are fabricated with CMOS compatible and wafer-scale technology.

Hybrid modeling approach for mode-locked laser diodes with cavity dispersion and nonlinearity.

Semiconductor-based mode-locked lasers, integrated sources enabling the generation of coherent ultra-short optical pulses, are important for a wide range of applications, including datacom, optical ranging and spectroscopy. As their performance remains largely unpredictable due to the lack of commercial design tools and the poorly understood mode-locking dynamics, significant research has focused on their modeling. In recent years, traveling-wave models have been favored because they can efficiently incorporate the rich semiconductor physics of the laser. However, thus far such models struggle to include nonlinear and dispersive effects of an extended passive laser cavity, which can play an important role for the temporal and spectral pulse evolution and stability. To overcome these challenges, we developed a hybrid modeling strategy by unifying the traveling-wave modeling technique for the semiconductor laser sections with a split-step Fourier method for the extended passive laser cavity. This paper presents the hybrid modeling concept and exemplifies for the first time the significance of the third order nonlinearity and dispersion of the extended cavity for a 2.6 GHz III-V-on-Silicon mode-locked laser. This modeling approach allows to include a wide range of physical phenomena with low computational complexity, enabling the exploration of novel operating regimes such as chip-scale soliton mode-locking.