Search

Session Photodetection (SM3K); International audience; Next-generation telecommunication systems will rely on photonic integrated circuits. However, Silicon Nitride (SiN) photonic platforms do not natively provide high-speed photodiodes. We integrated a waveguide-coupled UTC photodiode on a SiN platform using the scalable micro-transfer-printing technology. These diodes show a responsivity up to 0 . 45 A/W, a dark current below 10 nA and a 3 dB-bandwidth beyond 100 GHz, even at zero-bias. As such, high-performance photodetectors are available on silicon-nitride photonic platforms.

Microtransfer printing of silicon and lithium niobate thin films on generic integrated photonic platforms is demonstrated. An unprecedented integration yield is achieved using crack barriers as a way to mitigate stress-induced shears in the material.

We demonstrate the first on-chip resonant electro-optic frequency comb source on thin-film lithium niobate with an electrically-pumped heterogeneously integrated laser.

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. (c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Heterogeneous laser integration usually entails a platform-dependent process flow and design. We experimentally show a single-mode laser that can be printed on all platforms with n plat f orm = 1.7 − 2.3 without changing the design or process flow.

Current fiber-based mode-locked lasers are already used in several applications, such as laser eye surgery and spectrograph calibration in the hunt for exoplanets. Miniaturizing and integrating such lasers can enable mass production which could result in new applications, for example distributed sensing of greenhouse gasses [1] and high-performance ranging [2] . Currently, the best performing integrated mode-locked lasers use an extended on-chip cavity. These have been shown on single chips in several III/V and heterogeneous platforms, by using active waveguides for gain, and passive waveguides for the low loss extended cavity [3] , [4] . In this work, these lasers are improved upon by butt-coupling an SiN extended cavity to the gain waveguides in a generic III/V platform, replacing the relatively lossy passive InP waveguides.

High-speed photodiodes often compromise responsivity in exchange for a reduced footprint. However, using waveguide photodiodes circumvents this limitation [1] . We combine uni-travelling-carrier photodiodes (UTC PDs) on a silicon nitride (SiN) photonic platform to achieve both high responsivity and high speed detectors. The SiN-platform has excellent properties such as low-loss waveguides and does not suffer from two-foton absorption at high optical power. A high responsivity is obtained through evanescent coupling of waveguide UTC photodiodes to SiN waveguides while still maintaining a small footprint.

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.

A dual-comb interferometer with two semiconductor lasers on silicon photonic chips enables an optical resolution of 1 GHz, over a 0.7-THz span. The spectrometer di- rectly and unambiguously samples near-infrared rovibrational transitions without spectral interleaving.

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.

Successful micro-transfer printing of lithium niobate on a silicon nitride platform is demonstrated. A proof of concept electro-optical modulator is fabricated using this hybrid integration method which shows a half-wave voltage-length product $V_{\pi}L_{\pi}=5.5\ Vcm$ and insertion losses of 7 dB.

We demonstrate dual-comb interferometry and spectroscopy with a III-V-on-silicon passively mode- locked laser of 1-GHz repetition rate and 1-THz span. We heterodyne the on-chip device with an electro-optic modulator comb for initial assessment. (C) 2020 The Author(s)

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.

An integrated III-V-on-silicon mode-locked laser enables the first on-chip comb generator of 1.0-GHz line-spacing for direct interrogation of gas-phase narrow rovibrational transitions in molecules. Its flat-top spectrum empowers real-time multiplexed spectroscopy without any scanning elements.

We demonstrate electrically pumped, heterogeneously integrated lasers on thin-film lithium niobate, featuring electro-optic wavelength tunability.

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.

A novel hybrid integration strategy for compact, broadband, and highly efficient millimeter-wave (mmWave) on-chip antennas is demonstrated by realizing a hybrid on-chip antenna, operating in the [27.5–29.5] GHz band. A cavity-backed stacked patch antenna is implemented on a 600 $\mu$ m thick silicon substrate by using air-filled substrate-integrated-waveguide technology. A hybrid on-chip approach is adopted in which the antenna feed and an air-filled cavity are integrated on-chip, and the stacked patch configuration is implemented on a high-frequency printed circuit board (PCB) laminate that supports the chip. A prototype of the hybrid on-chip antenna is validated, demonstrating an impedance bandwidth of 3.7 GHz. In free-space conditions, a boresight gain of 7.3 dBi and a front-to-back ratio of 20.3 dB at 28.5 GHz are achieved. Moreover, the antenna is fabricated using standard silicon fabrication techniques and features a total antenna efficiency above 90% in the targeted frequency band of operation. The high performance, in combination with the compact antenna footprint of $\text{0.49}\,\lambda _{\rm min} \times \text{0.49}\,\lambda _{\rm min}$ , makes it an ideal building block to construct broadband antenna arrays with a broad steering range.

Integrated semiconductor mode-locked lasers have shown promise in many applications and are readily fabricated using generic InP photonic integration platforms. However, the passive waveguides offered in such platforms have relatively high linear and nonlinear losses that limit the performance of these lasers. By extending such lasers with, for example, an external cavity the performance can be increased considerably. In this paper, we demonstrate for the first time that a high-performance mode-locked laser can be achieved with a butt-coupling integration technique using chip scale silicon nitride waveguides. A platform-independent SiN/SU8 coupler design is used to couple between the silicon nitride external cavity and the III/V active chip. Mode-locked lasers at 2.18 GHz and 15.5 GHz repetition rates are demonstrated with Lorentzian RF linewidths several orders of magnitude smaller than what has been demonstrated on monolithic InP platforms. The RF linewidth was 31 Hz for the 2.18 GHz laser., Submitted to Optics Express

A heterogeneously integrated III-V-on-silicon nitride mode-locked laser is demonstrated. The device is fabricated by microtransfer printing an InP/InAlGaAs-based multiple-quantum-well coupon. A dense comb with a 755 MHz repetition rate, a 1 Hz ASE limited RF linewidth and a 200 kHz optical linewidth is achieved.