Phys.org October 11, 2024 Enhanced nonlinear processes in microresonators have emerged as a mainstream comb-generating mechanism with compelling advantages in size, weight, and power consumption. The established understanding of gain and loss in nonlinear microresonators, along with recently developed ultralow-loss nonlinear photonic circuitry, has boosted the optical energy conversion efficiency of microresonator frequency comb (microcomb) devices from below a few percent to above 50%. In this review an international team of researchers (USA – Caltech, Harvard University, Sweden) summarized the latest advances in novel photonic devices and pumping strategies that contributed to these milestones of microcomb efficiency. The resulting benefits […]
Tag Archives: Microresonators
New photonic chip spawns nested topological frequency comb
Phys.org June 20, 2024 On-chip frequency combs have relied predominantly on single-ring resonators. A team of researchers in the US (University of Maryland, University of Illinois, Northeastern University) experimentally demonstrated the generation of topological frequency combs, in a two-dimensional lattice of hundreds of ring resonators that hosts fabrication-robust topological edge states with linear dispersion. By pumping these edge states, they demonstrated the generation of a nested frequency comb that showed oscillation of multiple edge state resonances across ≈40 longitudinal modes and was spatially confined at the lattice edge. According to the researchers their results provide an opportunity to explore the […]
Scientists greatly expand the frequencies generated by a miniature optical ruler
Phys.org February 23, 2022 A team of researchers in the US (NIST, University of Maryland) has produced a microcomb using two lasers, each generating a different frequency of light, instead of just one. They found that through a complex series of interactions with the soliton light circulating in the microring resonator, the second laser induced two new sets of teeth, or evenly spaced frequencies, that are replicas of the original set of teeth but shifted to higher and lower frequencies. The lower frequency set lies in the infrared part of the spectrum, while the other is at much high frequencies, […]
New tech builds ultralow-loss integrated photonic circuits
Phys.org April 16, 2021 Researchers in Switzerland have developed a new technology for building silicon nitride integrated photonic circuits with record low optical losses and small footprints. They used Damascene process to make integrated circuits of optical losses of only 1 dB/m. Such low loss significantly reduces the power budget for building chip-scale optical frequency combs (“microcombs”), used in applications like coherent optical transceivers, low-noise microwave synthesizers, LiDAR, neuromorphic computing, and even optical atomic clocks. The team used the new technology to develop meter-long waveguides on 5×5 mm2 chips and high-quality-factor microresonators. They also report high fabrication yield, which is […]
Trapping light without back reflections
Phys.org January 4, 2021 Due to material imperfections, some amount of light is reflected backwards in microresonators which disturbs their function. To reduce the unwanted backscattering an international team of researchers (UK, Germany) used the principle of noise cancelling headphone and introduced out-of-phase light to cancel out optical interference. To generate the out-of-phase light, the researchers position a sharp metal tip close to the microresonator surface. The tip also causes light to scatter backwards. As the phase of the reflected light can be chosen by controlling the position of the tip, backscattered light’s phase can be set so it annihilates […]