Lasers are ubiquitous in science and technology, with applications ranging from optical communications and quantum technologies to metrology and sensing and to life sciences and medical diagnostics. Lasers are equally at the heart of numerous emerging quantum technologies, ranging from control of trapped ions for quantum computing, Rydberg atoms for field sensors, lasers to interrogate atoms for the world’s most precise atomic clocks based on laser cooled atoms in lattices. For wider deployment of such quantum technologies in the field, airborne or in space, the miniaturization of high-performance narrow linewidth laser sources is imperative. 

However, most commercially available lasers are still based on legacy technical schemes, requiring manual assembly from discrete components (fibers, diffraction grating, mirrors) or utilizing rather basic III-V semiconductor structures. These devices are either bulky and expensive – and thus prevent the adoption of novel types of photonic systems for mass production and high-volume applications. The advent of advanced photonic integration platforms such as silicon photonics has led to very compact chipbased lasers. This evolution was mainly driven by high-speed communications in exa-scale data centers, and these sources lack wavelength coverage or precise frequency tunability required for the challenging quantum and sensing applications such as quantum radio-frequency sensors and lasers for optical atomic clocks. For example, in the context of Doppler laser cooling, it is essential for the laser’s linewidth to be significantly smaller than that of the atom to achieve low temperatures. To achieve optimal performance, it is crucial to have a laser with a well-defined, stable, and precisely adjustable absolute wavelength. For mass adoption of quantum technologies such lasers should have a compact footprint and be low-cost. 

Deeplight aims to establish a new class of integrated lasers capable of operating across the UV to visible spectrum, starting from the blue region (400 nm). These lasers target key wavelengths relevant to laser-cooled atoms and trapped ions. Si₃N₄-based integrated photonic lasers have already demonstrated record-low phase noise and exceptional frequency agility in the near-infrared, surpassing the performance of conventional fiber lasers. In this project, Deeplight extended this approach into the visible range, developing a platform that integrates ultra-low-loss Si₃N₄ photonic circuits with advanced piezoelectric thin-film tuning actuators and III-V gain elements. The resulting devices are designed to deliver high output powers, laser linewidths in the Hz to kHz range, and unprecedented frequency agility with nanosecond-level response times.

As part of this activity: 

• Fully packaged hybrid integrated lasers operating at 1550 nm with spiral cavities have been demonstrated, exhibiting Lorentzian linewidths 10 dB lower than those of fiber lasers. For example, the frequency noise reaches 10 Hz²/Hz at a 10 kHz offset.
• Hybrid integrated lasers featuring 1.5 GHz and 250 MHz spiral cavities, along with AlN actuators, have been developed to enable high-speed modulation of ultra-low noise lasers. These devices are well-suited for air- and space-borne coherent sensing applications, including free-space coherent optical communication.
• For the first time, a sub-micron laser compatible with laser diodes ranging from 780 nm to 1000 nm has been demonstrated, incorporating monolithically integrated MEMS piezoelectric actuators for fast and precise frequency control. The device achieves a laser frequency actuation bandwidth exceeding 10 MHz, with a frequency excursion range greater than 1 GHz and a tuning efficiency of 35 MHz/V. Linear chirping of the laser has been demonstrated with sweep rates up to 500 kHz. Fully packaged devices with kHz-level linewidths are available for testing.
• A hybrid integrated, widely tunable laser around 900 nm has been demonstrated, delivering 11 mW of output power and kHz-level linewidths. Samples with output powers exceeding 30 mW in single-mode fiber have been achieved by optimizing the Si₃N₄ platform and mode converters. Further optimization could enable output powers up to 100 mW. Fully packaged devices are available for testing.
• A hybrid integrated blue laser has been demonstrated with linewidths around 100 kHz. Frequency agility has been shown through chirping with sweep rates up to 500 kHz.
• Prototypes have been tested with early adopters of the technology, and the results have been disseminated. Deeplight has planned extensive exploitation in collaboration with partners, targeting breakthrough demonstrations in quantum technologies and compact system demonstrators.