Discover new measurement optical frequency combs

Occasional light pulses create a comb in the frequency range widely used for sensitivity and range. The key to analyzing this technology toward chip integrated solutions is the generation of dissipative solitons in ring-shaped microresonators. Dissipative solitons are stable pulses that revolve around an abnormal resonator circuit.

Since their first presentation, the process of dissipative soliton formation has been extensively studied and today it is considered a textbook experience. A number of development guidelines are being actively reviewed by various research organizations around the world. One of these guidelines is the generation of solitons in twin resonators. The general effect of many rectifiers promises better performance and control of the frequency combinations, taking advantage of the opposite (spatial).

But how does the combination of additional resonators alter the soliton generation process? Identity oscillators of any kind, which are mutually exclusive, cannot be considered as a set of specific elements. As a result of the hybridization phenomenon, the excitation of such a system affects all of its elements, and the system must be manipulated as a whole. The simplest case is when the crosslinking occurs two connected oscillators or, in molecular terms, a dimer. In addition to connected pendulums and molecular-forming atoms, the methods of connected optical microresonators undergo transitions but, compared to other systems, the number of modes involved is large (usually from tens to hundreds). Thus, solitons in a photonic dimer are generated in hybrid modes that incorporate both resonators, which contributes to a different level of control if one of them has access to hybridization parameters.

In a paper published at Physics of nature, researchers from Tobias J. Kippenberg ‘s laboratory at EPFL, and IBM Research Europe led by Paul Seidler, demonstrated the generation of dissipative solitons and, therefore, sensible frequency combinations in photonic molecules composed of two microresonators. Soliton generation in the dimer means two anti-propagating solids in the two resonator cycles. The basic electric field behind each mode of the dimer is similar to two gears rotating in other directions, which is why solitons in the photonic dimer are called Gear Solitons. Influencing heaters on both resonators, thus controlling the transition, authors showed real-time tuning of the soliton-based frequency comb.

Even the simple dimer arrangement, in addition to the hybrid soliton (gear) generation, has revealed a number of remarkable features, ie onions that are not present at the one-part (resonator) level. For example, researchers predicted the effect of soliton hopping: periodic energy exchange between the resonators forming the dimer while maintaining the solitonic state. This phenomenon is due to the simultaneous generation of solitons in each hybridised mode family whose interaction leads to energy oscillation. Soliton hopping, for example, can be used to create sensible combs in the radio frequency range.

“The physics of soliton generation in a single resonator is largely understood today,” says Alexey Tikan, a researcher at EPFL’s Photonics and Quantum Photography Laboratory. “The field explores other development and development directions. Twin resonators are one of the few such perspectives. This approach allows you to recruit concepts from nearby physics fields. For example, one can creation of topology insulator (known in solid state physics) by bonding resonators in surfaces, which leads to the generation of strong frequency combs resistant to surface defects, while at the same time benefiting from improved efficiency and control levels. Our work will be a step towards these exciting ideas! ”

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