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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.

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

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.

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.

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.