The propagation of coherent light in multimode optical fibers results in a speckled output that is both complex and sensitive to environmental effects.These properties can be a powerful tool for sensing,as small pertu...The propagation of coherent light in multimode optical fibers results in a speckled output that is both complex and sensitive to environmental effects.These properties can be a powerful tool for sensing,as small perturbations lead to significant changes in the output of the fiber.However,the mechanism to encode spatially resolved sensing information into the speckle pattern and the ability to extract this information are thus far unclear.In this paper,we demonstrate that spatially dependent mode coupling is crucial to achieving spatially resolved measurements.We leverage machine learning to quantitatively extract the spatially resolved sensing information from three fiber types with dramatically different characteristics and demonstrate that the fiber with the highest degree of spatially dependent mode coupling provides the greatest accuracy.展开更多
Nonlinear frequency conversion is a pathway to unlock undiscovered physics and implement tailored light sources for spectroscopy or medicine.A key challenge is the establishment of spectrally flat outputs,which is par...Nonlinear frequency conversion is a pathway to unlock undiscovered physics and implement tailored light sources for spectroscopy or medicine.A key challenge is the establishment of spectrally flat outputs,which is particularly demanding in the context of soliton-based light conversion at low pump energy.Here,we introduce the concept of controlling nonlinear frequency conversion by longitudinally varying resonances,allowing the shaping of soliton dynamics and achieving broadband spectra with substantial spectral flatness.Longitudinally varying resonances are realised by nanofilms with gradually changing thicknesses located on the core of an advanced microstructured fibre.Nanofilms with engineered thickness profiles are fabricated by tilted deposition,representing a waveguidecompatible approach to nano-fabrication,and inducing well-controlled resonances into the system,allowing unique dispersion control along the fibre length.Key features and dependencies are examined experimentally,showing improved bandwidth and spectral flatness via multiple dispersive wave generation and dispersionassisted soliton Raman shifts while maintaining excellent pulse-to-pulse stability and coherence in simulations,suggesting the relevance of our findings for basic science as well as tailored light sources.展开更多
基金Australian Government Research Training Program ScholarshipsAustralian National Fabrication FacilityAustralian Research Council(CE170100004,FT200100154)。
文摘The propagation of coherent light in multimode optical fibers results in a speckled output that is both complex and sensitive to environmental effects.These properties can be a powerful tool for sensing,as small perturbations lead to significant changes in the output of the fiber.However,the mechanism to encode spatially resolved sensing information into the speckle pattern and the ability to extract this information are thus far unclear.In this paper,we demonstrate that spatially dependent mode coupling is crucial to achieving spatially resolved measurements.We leverage machine learning to quantitatively extract the spatially resolved sensing information from three fiber types with dramatically different characteristics and demonstrate that the fiber with the highest degree of spatially dependent mode coupling provides the greatest accuracy.
基金support of the German Science Foundation via the Projects SCHM2655/9-1,SCHM2655/11-1,and SCHM2655/12-1This work was performed in part at the Optofab node of the Australian National Fabrication Facility(ANFF)utilising Commonwealth and South Australian State Government Funding.T.L.acknowledges support from the German Science Foundation DFG,IRTG 2101.H.E.and E.S.acknowledge support from the ARC Centre of Excellence for Nanoscale Biophotonics(CE140100003).
文摘Nonlinear frequency conversion is a pathway to unlock undiscovered physics and implement tailored light sources for spectroscopy or medicine.A key challenge is the establishment of spectrally flat outputs,which is particularly demanding in the context of soliton-based light conversion at low pump energy.Here,we introduce the concept of controlling nonlinear frequency conversion by longitudinally varying resonances,allowing the shaping of soliton dynamics and achieving broadband spectra with substantial spectral flatness.Longitudinally varying resonances are realised by nanofilms with gradually changing thicknesses located on the core of an advanced microstructured fibre.Nanofilms with engineered thickness profiles are fabricated by tilted deposition,representing a waveguidecompatible approach to nano-fabrication,and inducing well-controlled resonances into the system,allowing unique dispersion control along the fibre length.Key features and dependencies are examined experimentally,showing improved bandwidth and spectral flatness via multiple dispersive wave generation and dispersionassisted soliton Raman shifts while maintaining excellent pulse-to-pulse stability and coherence in simulations,suggesting the relevance of our findings for basic science as well as tailored light sources.
