We demonstrate a 23.3 GHz GaAs-on-SiN mode-locked laser heterogeneously integrated on a commercial SiN platform using micro-transfer printing. A compact Fabry-Pérot cavity with a central saturable absorber enables colliding-pulse, second-harmonic mode locking. The device delivers up to 1 mW on-chip optical power from a single output port and generates eight comb lines within a 10 dB optical bandwidth. The pulse-forming operation is confirmed by autocorrelation measurements, yielding a deconvolved pulse width of 4.8 ps. This approach provides a scalable route toward electrically pumped high-repetition-rate pulse sources for nonlinear SiN photonic circuits.

Kerr frequency combs,or microcombs,are revolutionizing fields such as precision metrology,optical clocks,and astronomical spectrometer calibration.However,conventional dissipative Kerr soliton(DKS)microcombs often suffer from limited conversion efficiency and low output power,and achieving deterministic single-soliton gen-eration remains a challenge due to limited thermal accessibility arising from the intricate interplay of Kerr and thermal effects.In this work,we present an optimized microresonator design combined with a robust pumping scheme to enhance the thermal accessibility of single-soliton states for deterministic generation.By operating a silicon nitride microresonator with tailored dispersion in the over-coupled regime,we demonstrate a thermally accessible pathway to single solitons with high conversion efficiency(approaching 30％),and high output power(up to 50 mW).Through a pump forward-tuning process with power ramping,followed by backward tuning,we achieve deterministic single-soliton generation across 80 consecutive trials via automated laser tuning,eliminating the need for complex thermal compensation or rapid tuning schemes.Our work provides a straightforward and robust solution for generating high-power solitons,advancing the practicality and accessibility of microcombs for real-world applications.

High-power amplifiers are critical components in optical systems spanning from long-range optical sensing and optical communication systems to micromachining and medical surgery. Today, integrated photonics with its promise of large reductions in size, weight and cost cannot be used in these applications, owing to the lack of on-chip high-power amplifiers. Integrated devices severely lack in output power owing to their small size, which limits their energy storage capacity. For the past two decades, large mode area (LMA) technology has played a disruptive role in fibre amplifiers, enabling a dramatic increase of output power and energy by orders of magnitude. Owing to the ability of LMA fibres to support significantly larger optical modes, the energy storage and power handling capabilities of LMA fibres have significantly increased. Therefore, an LMA device on an integrated platform can play a similar role in power and energy scaling of integrated devices. In this work, we demonstrate LMA waveguide-based watt-class high-power amplifiers in silicon photonics with an on-chip output power exceeding ~1 W within a footprint of only ~4.4 mm2. The power achieved is comparable and even surpasses that of many fibre-based amplifiers. We believe that this work has the potential to radically change the integrated photonics application landscape, allowing power levels previously unimaginable from an integrated device to replace much of today’s benchtop systems. Moreover, mass producibility, reduced size, weight and cost will enable yet unforeseen applications of laser technology. A CMOS-compatible watt-class power amplifier based on large-mode waveguide technology is realized with an on-chip output power reaching ~1 W within a footprint of ~4 mm2, enabling integrated photonics to tackle true systems level integration.

This work presents a dual plasmo-photonic branch Mach-Zehnder interferometer refractive index sensor integrated on a Si3N4 platform, with both the sensor and reference arms hosting identical aluminum plasmonic metal stripes. Experimental evaluation of the configuration reveals a bulk sensitivity up to 8801 nm/RIU and an increased environmental noise resilience compared to state-of-the-art plasmo-photonic MZI sensors with the plasmonic section residing only on the sensor arm. The enhanced noise resilience along with the high sensitivity results in an experimentally obtained low detection limit value of 4.4 x 10-6 RIU, im-proved by an order of magnitude compared to the detection limit of 5 x 10-5 RIU that was measured in a reference MZI sensor with a plasmonic stripe only at its sensor arm.

We present the latest results on heterogeneously integrated mode-locked lasers on a commercial SiN platform. Both O- and C-band operations were achieved on a single chip by integrating GaAs- and InP-based gain materials. © 2025 The Author(s)

We present an O-band GaAs optical amplifier integrated on an advanced SiN platform using micro-transfer printing. A polycrystalline Si layer facilitates light coupling between GaAs and SiN, resulting 5 dB on-chip gain at 1300 nm.

High-power tunable lasers are intensely pursued due to their vast application potential such as in telecom, ranging, and molecular sensing. Integrated photonics, however, is usually considered not suitable for high-power applications mainly due to its small size which limits the energy storage capacity and, therefore, the output power. In the late 90s, to improve the beam quality and increase the stored energy, large-mode-area (LMA) fibers were introduced in which the optical mode area is substantially large. Such LMA fibers have transformed the high-power capability of fiber systems ever since. Introducing such an LMA technology at the chip-scale can play an equally disruptive role with high power signal generation from an integrated photonics system. To this end, in this work we demonstrate such a technology, and show a very high-power tunable laser with the help of a silicon photonics based LMA power amplifier. We show output power reaching 1.8 W over a tunability range of 60 nm, spanning from 1.83 µm to 1.89 µm, limited only by the seed laser. Such an integrated LMA device can be used to substantially increase the power of the existing integrated tunable lasers currently limited to a few tens of milliwatts. The power levels demonstrated here reach and surpass that of many benchtop systems which truly makes the silicon photonics based integrated LMA device poised towards mass deployment for high power applications without relying on benchtop systems.

Continuous-wave (CW) laser-driven integrated Kerr microresonators enable broadband optical frequency combs with high repetition rates and low threshold power, in a compact footprint. A drawback of such microcombs is the low conversion efficiency from the pump laser to the comb lines, which is often in the few percent range or below. In recent works, improved conversion efficiency has been demonstrated by leveraging soliton crystal states [1], interferometric back-coupling to suppress the residual pump light [2], or tuning the resonance frequency of the pumped mode [3]. While these approaches achieve improved conversion efficiency, they add complexity to the design and operation of the system, relying on non-deterministic states, dynamic control, and/or a potentially reduced number of comb lines.

Dissipative Kerr solitons (DKS), which provide coherent and stable frequency combs, have emerged as a powerful tool for a wide range of applications in metrology, spectroscopy, telecommunications [1]. However, one of the major challenges hindering their practical deployment is the inherently low pump-to-comb conversion efficiency [2], [3], which is typically restricted to only a few percent. Recent advances have introduced promising strategies to enhance conversion efficiency in single-soliton states, including new pumping schemes such as pulsed pumping [4] and novel cavity designs like photonic molecules [5]. Nevertheless, existing high-efficiency demonstrations have thus far been constrained by limited optical bandwidths, falling short of the broad spectral coverage required for demanding applications such as self-referencing and broadband spectroscopy.

Dissipative Kerr solitons in optical microresonators have emerged as a powerful tool for compact and coherent frequency comb generation. Advances in nanofabrication have allowed precise dispersion engineering, unlocking octave-spanning soliton combs that are essential for applications such as optical atomic clocks, frequency synthesis, precision spectroscopy, and astronomical spectrometer calibration. However, a key challenge hindering their practical deployment is the intrinsic bandwidth-efficiency trade-off: achieving broadband soliton generation requires large pump detuning, which suppresses power coupling and limits pump-to-comb conversion efficiencies to only a few percent. Recent efforts using pulsed pumping or coupled-resonator architectures have improved efficiency to several tens of percent, yet their bandwidths remain below one-tenth of an octave, inadequate for applications demanding wide spectral coverage. Here, we overcome this limitation by harnessing mode interactions between spatial modes within a single microresonator. The mode hybridization creates an additional power-transfer channel that supports large pump detuning while maintaining strong pump-to-resonator coupling, enabling broadband soliton formation at substantially reduced pump power. Using this approach, we demonstrate an octave-spanning soliton microcomb with a record pump-to-comb conversion efficiency exceeding 50

We present a coupled-mode pumping strategy that overcomes the long-standing trade-off between conversion efficiency and optical bandwidth in soliton microcombs. Using this approach, we experimentally demonstrate an octave-spanning single soliton microcomb that achieves nearly 50% pump-to-comb conversion efficiency. (c) 2025 The Author(s)

We demonstrate a widely tunable laser amplified to high power with a CMOS-compatible integrated LMA power amplifier. We show amplified power up to 1.5 W from around 100 mW of input seed power in the wavelength window spanning from 1800 to 1900 nm.

Chip-scale, high-energy optical pulse generation is becoming increasingly important as integrated optics expands into space and medical applications where miniaturization is needed. Q -switching of the laser cavity was historically the first technique to generate high-energy pulses, and typically such systems are in the realm of large bench-top solid-state lasers and fibre lasers, especially in the long wavelength range >1.8 µm, thanks to their large energy storage capacity. However, in integrated photonics, the very property of tight mode confinement that enables a small form factor becomes an impediment to high-energy applications owing to small optical mode cross-sections. Here we demonstrate a high-energy silicon photonics-based passively Q -switched laser with a compact footprint using a rare-earth gain-based large-mode-area waveguide. We demonstrate high on-chip output pulse energies of >150 nJ and 250 ns pulse duration in a single transverse fundamental mode in the retina-safe spectral region (1.9 µm), with a slope efficiency of ~40% in a footprint of ~9 mm 2 . The high-energy pulse generation demonstrated in this work is comparable to or in many cases exceeds that of Q -switched fibre lasers. This bodes well for field applications in medicine and space.

Femtosecond laser pulses enable the synthesis of light across the electromagnetic spectrum and provide access to ultrafast phenomena in physics, biology, and chemistry. Chip-integration of femtosecond technology could revolutionize applications such as point-of-care diagnostics, biomedical imaging, portable chemical sensing, or autonomous navigation. However, current sources lack the required power, and the on-chip amplification of femtosecond pulses is an unresolved challenge. Here, addressing this challenge, we report >50-fold amplification of 1 GHz-repetition-rate chirped femtosecond pulses in a CMOS-compatible photonic chip to 800 W peak power with 116 fs pulse duration. Nonlinear effects, usually a hallmark of integrated photonics but prohibitive to pulse amplification are mitigated through all-normal dispersion, large mode-area rare-earth-doped gain waveguides. These results offer a pathway to chip-integrated femtosecond technology with power-levels characteristic of table-top sources.

Continuous-wave (CW) laser-driven integrated Kerr microresonators enable broadband optical frequency combs with high repetition rates and low threshold power, in a compact footprint. A drawback of such microcombs is the low conversion efficiency from the pump laser to the comb lines, which is often in the few percent range or below. Here, complementing previously demonstrated approaches to increase conversion efficiency, we demonstrate a novel approach that leverages a chip-based rare-earth (Tm3+)-doped optical gain medium to boost the pump-to-comb conversion efficiency by more than one order of magnitude. Importantly, the gain medium does not require an additional pump laser, but recycles residual pump light from the Kerr-comb: the CW pump of the Kerr-comb (1610 nm) coincides with the pump wavelength of the on-chip gain medium, allowing unconverted pump power to be absorbed and transferred to the comb lines within gain window (1700 - 1900 nm). This enables a new class of highly efficient Kerr-combs for applications e.g. in data centers and optical computing.

We demonstrate a high-power tunable laser based on a CMOS-compatible power-amplifier. We show amplified power up to 1.8 W with a tunability bandwidth of 60 nm from 1.83 µm to 1.89 µm, limited only by the seed laser. Additionally, high power amplification up to 1.95 µm is demonstrated with the potential for tunability over a larger window, 1.8 to > 2 µm.

We demonstrate high energy Q-switched pulse generation with the help of a large mode area gain waveguide in a silicon photonics device. Output pulse energy >150 nJ and laser slope efficiency of 40% is shown.

We demonstrate for the first-time f emtosecond p ulse a mplification in a CMOS-compatible photonic chip. We report > 50-fold amplification of 1 GHz-repetitionrate chirped femtosecond pulses to 800 W of on-chip peak power with 116 fs pulse duration.

High power amplifiers are critical components in optical systems spanning from long range optical sensing and optical communication systems to micromachining and medical surgery. Today, integrated photonics with its promise of large reductions in size, weight and cost cannot be used in these applications, due to the lack of on-chip high power amplifiers. Integrated devices severely lack in output power due to their small size which limits energy storage capacity. For the last two decades, large mode area (LMA) technology has played a disruptive role in fiber amplifiers enabling a dramatic increase of output power and energy by orders of magnitude. Thanks to the capability of LMA fiber to support significantly larger optical modes the energy storage and power handling capability has significantly increased. Therefore, an LMA device on an integrated platform can play a similar role in power and energy scaling of integrated devices. In this work, we demonstrate LMA waveguide-based CMOS compatible watt-class high power amplifiers with an on-chip output power reaching beyond ~ 1 W within a footprint of only ~ 4 mm2. The power achieved is comparable and even surpasses many fiber-based amplifiers. We believe this work has the potential to radically change the integrated photonics application landscape, allowing power levels previously unimaginable from an integrated device replacing much of today’s benchtop systems. Moreover, mass producibility, reduced size, weight and cost will enable yet unforeseen applications for laser technology.