Optical solitons are packets of non-linear optical waves that can maintain their profile during propagation even in the presence of moderate disturbances, offering useful applications in optical communications, all-optical information processing as well as ultra-fast laser techniques. . The interaction between optical solitons exhibits many particle-like properties and has been widely studied for decades. In particular, the bound states of optical solitons in nonlinear dissipative systems, resulting from balanced interactions, have been shown to manifest unique analogies between matter and light and are embodied by “soliton molecules” – multi-structures. compact solitons which propagate as invariants. unique entities.
The dynamics of soliton molecules has aroused great interest, in particular the synthesis and dissociation of soliton molecules that are reminiscent of chemical reactions. However, the study of soliton molecules relied mainly on uncontrolled random excitations and has long stabilized at the level of a single object without exploring the stochastic and statistical properties that involve massive numbers of solitons, making it difficult to conducting a higher level study of several soliton dynamics.
In a new article published in Light science and application, a team of scientists, led by Dr Wenbin He and Dr Meng Pang from Prof. Philip Russell’s division of the Max Planck Institute for Light Science in Germany, developed a unique platform, called ‘reactors parallel soliton optics ”that can host massively dynamic events of soliton molecules. Such parallel reactors, resembling chemical reactors, can isolate and host multiple solitons, and then manipulate their interactions by various all-optical methods.
When hundreds of these parallel reactors operate simultaneously with carefully prepared initial states and control techniques, the on-demand synthesis and dissociations of soliton molecules can be initiated in large numbers, unfolding a new panorama of multi-soliton dynamics. stochastic nature. In addition, statistical rules are found from massively parallel reactions which closely resemble classical chemical kinetics, which promote the conventional matter-light analogy on a collective level. These results shed a higher level of light on the dynamics of solitons which can benefit both fundamental research for nonlinear systems, but also practical applications involving a massive number of optical solitons.
Parallel optical-soliton reactors are based on a unique optomechanical network that is created using an optoacoustic mode-locked fiber laser. The key component is actually just a short piece of Photonic Crystal Fiber (PCF) – a special microstructured optical fiber that has a micro-core surrounded by an array of hollow channels. These scientists summarize the principle of operation of their parallel reactors:
“Micro-core PCF-based optoacoustic mode-locked fiber lasers, which have been developed in our laboratory for many years, utilize the enhanced optoacoustic interactions in the micro-core PCF. When inserted into a conventional locked-mode fiber laser, the PCF provides acoustic resonance, typically at a frequency of GHz, through which the multi-meter fiber cavity can be efficiently divided into hundreds of time slots, each corresponding to an acoustic vibration cycle, leading to the formation of an optomechanical network. Each timeslot, or “cell in a network” can host multiple solitons that are isolated from other timeslots and can be manipulated, functioning as parallel reactors in which the reactants are optical solitons instead of real atoms and molecules. “
“The major breakthrough of this work is the on-demand control of soliton interactions in each parallel reactor hosted by the optomechanical network. We have classified the methods into two types. One relied on the laser cavity disturbances that affect all reactors simultaneously, which is called “global control”. The other uses external addressing pulses to induce disturbances on selected reactors without affecting the others, which is called “individual control”. Long-range, phase-uncorrelated soliton interactions play an important role in such a controlled interaction. The controlled synthesis and dissociation of soliton molecules is in fact made possible by careful adaptation of long-distance soliton interactions.
“By carefully fitting the laser cavity, we have successfully initiated hundreds of soliton-molecule synthesis / dissociation events in parallel. We used the dispersive Fourier transform (DFT) method to capture the transient dynamics of multi-solitons in each reactor. By analyzing these massively parallel events recorded in the experiment, which are not available in previous studies, we unveiled many features of multi-soliton dynamics, including some statistical rules that emulate classical chemical kinetics, suggesting an analogy. matter-light at the collective level. “
“The technique presented offered a series of new possibilities for the study of optical solitons. Many phenomena regarding soliton dynamics can possibly be reexamined using such a parallel reactor scheme to gain collective insight. The various control techniques, in particular the individual control methods which have enabled the selective editing of multi-soliton states, can be potentially useful in optical information technologies which use solitons as bit carriers. We also expect the concept of parallel reactors to be realized in other platforms, for example using a massive set of micro-resonators. scientists predict.
Reference: “Synthesis and Dissociation of Soliton Molecules in Optical Parallel Soliton Reactors” by Wenbin He, Meng Pang, Dung-Han Yeh, Jiapeng Huang and Philip. St. J. Russell, June 7, 2021, Light: science and applications.
DOI: 10.1038 / s41377-021-00558-x