Latest news at LPNO

15 June 2020

Supercontinuum generation in media with sign-alternated dispersion
 

When an ultrafast optical pulse with high intensity propagates through transparent material a supercontinuum can be coherently generated by self‐phase modulation. However, the presence of dispersion causes stagnation of spectral broadening past a certain propagation length, requiring an increased input peak power for further broadening. Overcoming such spectral stagnation will be key to achieve practical integrated supercontinuum devices. Researchers of LPNO, together with colleagues from Optische Technologien at the University of Münster have developed a concept for improved supercontinuum generation by counteracting spectral stagnation via repeatedly alternating the sign of group velocity dispersion along the propagation. The effect is experimentally demonstrated using a dispersion alternating fiber and results are in excellent agreement with modeling, revealing almost an order of magnitude reduced peak power. Calculations show similar advantages using integrated optical waveguides resulting in a wide and flat spectrum, which is important for on‐chip broadband photonics (see also UT press release). Full article is available at Lasers & Photonics Review

 

10 June 2020

Work of LPNO and colleagues on cover page of Photonics Journal
 

Hybrid integrated diode laser are introducing a new paradigm to photonics, via providing unprecedented coherence, full spectral control, and seamless embedding in high-functionality photonic circuits. Most promising is hybrid integration with ultra-low loss dielectric feedback circuits as these render the widest spectral coverage including the visible range. We present work on various types and operational modes of hybrid-integrated diode lasers based on low-loss dielectric feedback circuits using silicon nitride waveguides. Highlights are the demonstration of sub-100-Hz intrinsic linewidth, up to 120 nm wide spectral coverage around a 1.55 µm wavelength, and more than 100 mW output power. Functionalities include dual-wavelength generation, dual-gain operation, laser frequency comb generation, and wavelength tunable feedback circuits for hybrid lasers in the visible. Full article is available at Photonics, 7, 4 (2020)

 

22 January 2019

Integrated microwave photonics

Photonics and radio signals join forces for high-speed mobile data communication, like in 5G communications. At the same time, the applications of ‘integrated microwave photonics’ go way beyond telecom. This progress often comes from directions you would not expect in the first place. In a review paper in Nature Photonics), David Marpaung gives together with experts Jianping Yao of the University of Ottawa and Jose Campany of the University of Valencia a vision on the next phase of photonic chips, for example in brain-inspired, ‘neuromorphic’ optical computing. (see also UT Press release).

10 August 2017

World's most narrowband diode laser on a chip

Researchers of the Laser Physics and Nonlinear Optics group developed, in collaboration with researchers of the Lionix Company, the world’s most narrowband diode laser on a chip exhibiting a quantum limited spectral bandwidth of less than 300 Hz. This laser concept represents a breakthrough in the fast-growing field of photonics, and will bring applications such as 5G internet and accurate GPS closer (see also UT Press release). 290Hzdef..