In this work we demonstrate the heterogeneous integration of active devices on the SiN photonic platform using micro-transfer printing and we will discuss the remaining technological challenges
Integrated photonic systems require fast modulators to keep up with demanding operation speeds and increasing data rates. The silicon nitride integrated photonic platform is of particular interest for applications such as datacom, light detection and ranging (LIDAR), quantum photonics, and computing owing to its low losses and CMOS compatibility. Yet, this platform inherently lacks high-speed modulators. Heterogeneous integration of lithium niobate on silicon nitride waveguides can address this drawback with its strong Pockels effect. We demonstrate the first high-speed lithium niobate modulator heterogeneously integrated on silicon nitride using micro-transfer printing. The device is 2 mm long with a half-wave voltage Vπ of 14.8 V. The insertion loss and extinction ratio are 3.3 and 39 dB, respectively. Operation beyond 50 GHz has been demonstrated with the generation of open eye diagrams up to 70 Gb/s. This proof-of-principle demonstration opens up possibilities for more scalable fabrication of these trusted and performant devices.
We demonstrate a III-V-on-silicon-nitride mode-locked laser through the heterogeneous integration of a semiconductor optical amplifier on a passive silicon nitride cavity using the technique of micro-transfer printing. Specifically, we explore the impact of the gain voltage and saturable absorber current on the locking stability of a tunable mode-locked laser. By manipulating these parameters, we demonstrate the control of the optical spectrum across a wide range of wavelengths spanning from 1530 nm to 1580 nm. Furthermore, we implement an optimization approach based on a Monte Carlo analysis aimed at enhancing the mode overlap within the gain region. This adjustment enables the achievement of a laser emitting a 23 nm wide spectrum while maintaining a defined 10 dB bandwidth for a pulse repetition rate of 3 GHz.
We demonstrate a novel hybrid model for semiconductor mode-locked lasers by combining the merits of a traveling-wave model for the active regions and a split-step Fourier algorithm for the extended passive cavity.
We demonstrate heterogeneously integrated passively mode-locked lasers by microtransfer printing III-V semiconductor optical amplifiers on a silicon nitride photonic chip. A dense and low-noise optical comb is generated, enabling unparalleled precision for on-chip spectroscopy.
Overcoming the high index contrast between SiN and III-V amplifiers is essential for the realization of heterogeneously integrated evanescently coupled lasers. Here, we propose a design based on a-Si:H as the transition layer, demonstrating sub-1.2 dB loss for the whole SiN-III/V-SiN transition at 920 nm.
We demonstrate a III-V-on-silicon-nitride mode-locked laser through the heterogeneous integration of a semiconductor optical amplifier on a passive silicon-nitride cavity using the technique of micro-transfer printing. In the initial phase of our study, we focus on optimizing the lasing wavelength to be centered at 1550 nm. This optimization is achieved by conducting experiments with 27 mode-locked lasers, each incorporating optical amplifiers featuring distinct multiple-quantum-well photoluminescence values. Subsequently we present a comprehensive study investigating the behavior of the mode-locking regime when the electrical driving parameters are varied. Specifically, we explore the impact of the gain voltage and saturable absorber current on the locking stability of a tunable mode-locked laser. By manipulating these parameters, we demonstrate the precise control of the optical spectrum across a wide range of wavelengths spanning from 1530 to 1580 nm. Furthermore, we implement an optimization approach based on a Monte Carlo analysis aimed at enhancing the mode overlap within the gain region. This adjustment enables the achievement of a laser emitting a 23-nm-wide spectrum while maintaining a defined 10 dB bandwidth for a pulse repetition rate of 3 GHz.
Abstract Generating optical combs in a small form factor is of utmost importance for a wide range of applications such as datacom, LIDAR, and spectroscopy. Electrically powered mode‐locked diode lasers provide combs with a high conversion efficiency, while simultaneously allowing for a dense spectrum of lines. In recent years, a number of integrated chip scale mode‐locked lasers have been demonstrated. However, thus far these devices suffer from significant linear and nonlinear losses in the passive cavity, limiting the attainable cavity size and noise performance, eventually inhibiting their application scope. Here, we leverage the ultra‐low losses of silicon‐nitride waveguides to demonstrate a heterogeneously integrated III‐V‐on‐silicon‐nitride passively mode‐locked laser with a narrow 755 MHz line spacing, a radio frequency linewidth of 1 Hz and an optical linewidth below 200 kHz. Moreover, these comb sources are fabricated with wafer scale technology, hence enabling low‐cost and high volume manufacturable devices.
External cavity mode-locked lasers could be used as comb sources for high volume application such as LIDAR and dual comb spectroscopy. Currently demonstrated chip scale integrated mode-locked lasers all operate in the C-band. In this paper, a hybrid-integrated external cavity mode-locked laser working at 1064 nm is demonstrated, a wavelength beneficial for optical coherence tomography or Raman spectroscopy applications. Additionally, optical injection locking is demonstrated, showing an improvement in the optical linewidth, and an increased stability of the comb spectrum.
A III-V/Si/Si 3 N 4 structure critical in realizing high-performance lasers can be fabricated using microtransfer printing. This approach poses stringent requirements on the $\text{Si}_{3}\mathrm{N}_{4}-\text{Si}$ couplers. Accordingly, we realized $174\ \mu \mathrm{m}$ long, fabrication-tolerant Si tapers with simulated losses below 0.8 dB up to 750 nm misalignment.
