High-power tunable lasers are intensely pursued due to their vast application potential such as in telecom,ranging,and molecular sensing.Integrated photonics,however,is usually considered not suitable for high-power a...High-power tunable lasers are intensely pursued due to their vast application potential such as in telecom,ranging,and molecular sensing.Integrated photonics,however,is usually considered not suitable for high-power applications mainly due to its small size which limits the energy storage capacity and,therefore,the output power.In the late 90s,to improve the beam quality and increase the stored energy,large-mode-area(LMA)fibers were introduced in which the optical mode area is substantially large.Such LMA fibers have transformed the high-power capability of fiber systems ever since.Introducing such an LMA technology at the chip-scale can play an equally disruptive role with high power signal generation from an integrated photonics system.To this end,in this work we demonstrate such a technology,and show a very high-power tunable laser with the help of a silicon photonics based LMA power amplifier.We show output power reaching 1.8 W over a tunability range of 60 nm,spanning from 1.83μm to 1.89μm,limited only by the seed laser.Such an integrated LMA device can be used to substantially increase the power of the existing integrated tunable lasers currently limited to a few tens of milliwatts.The power levels demonstrated here reach and surpass that of many benchtop systems which truly makes the silicon photonics based integrated LMA device poised towards mass deployment for high power applications without relying on benchtop systems.展开更多
Self-referencing turns pulsed laser systems into self-referenced frequency combs.Such frequency combs allow counting of optical frequencies and have a wide range of applications.The required optical bandwidth to imple...Self-referencing turns pulsed laser systems into self-referenced frequency combs.Such frequency combs allow counting of optical frequencies and have a wide range of applications.The required optical bandwidth to implement self-referencing is typically obtained via nonlinear broadening in optical fibers.Recent advances in the field of Kerr frequency combs have provided a path toward the development of compact frequency comb sources that provide broadband frequency combs,exhibit microwave repetition rates and are compatible with on-chip photonic integration.These devices have the potential to significantly expand the use of frequency combs.Yet to date,self-referencing of such Kerr frequency combs has only been attained by applying conventional,fiber-based broadening techniques.Here we demonstrate external broadening-free self-referencing of a Kerr frequency comb.An optical spectrum spanning two-thirds of an octave is directly synthesized from a continuous wave laser-driven silicon nitride microresonator using temporal dissipative Kerr soliton formation and soliton Cherenkov radiation.Using this coherent bandwidth and two continuous wave transfer lasers in a 2f–3f self-referencing scheme,we are able to detect the offset frequency of the soliton Kerr frequency comb.By stabilizing the repetition rate to a radio frequency reference,the self-referenced frequency comb is used to count and track the continuous wave pump laser’s frequency.This work demonstrates the principal ability of soliton Kerr frequency combs to provide microwave-to-optical clockworks on a chip.展开更多
Microcombs-optical frequency combs generated in microresonators-have advanced tremendously in the past decade,and are advantageous for applications in frequency metrology,navigation,spectroscopy,telecommunications,and...Microcombs-optical frequency combs generated in microresonators-have advanced tremendously in the past decade,and are advantageous for applications in frequency metrology,navigation,spectroscopy,telecommunications,and microwave photonics.Crucially,microcombs promise fully integrated miniaturized optical systems with unprecedented reductions in cost,size,weight,and power.However,the use of bulk free-space and fiber-optic comp on ents to process microcombs has restricted form factors to the table-top.Taking microcomb-based optical frequency synthesis around 1550 nm as our target application,here,we address this challenge by proposing an integrated photonics interposer architecture to replace discrete components by collecting,routing,and interfacing octave-wide microcomb-based optical signals between photonic chiplets and heterogeneously integrated devices.Experimentally,we con firm the requisite performa nee of the individual passive elements of the proposed interposer一octave-wide dichroics,multimode interferometers,and tunable ring filters,and implement the octave-spanning spectral filteri ng of a microcomb,central to the in terposer,using silicon n itride phot onics.Moreover,we show that the thick silicon nitride needed for bright dissipative Kerr soliton generation can be integrated with the comparatively thin silicon nitride interposer layer through octave-bandwidth adiabatic evanescent coupling,indicating a path towards future system-level consolidation.Fin ally,we numerically confirm the feasibility of operating the proposed in terposer synthesizer as a fully assembled system.Our interposer architecture addresses the immediate need for on-chip microcomb processing to successfully miniaturize microcomb systems and can be readily adapted to other metrology-grade applications based on optical atomic clocks and high-precision navigation and spectroscopy.展开更多
基金supported by EU Horizon 2020 Framework Programme—Grant Agreement No.:965124(FEMTOCHIP)Deutsche Forschungsgemeinschaft(SP2111)contract number PACE:Ka908/10-1Open Access funding enabled and organized by Projekt DEAL.
文摘High-power tunable lasers are intensely pursued due to their vast application potential such as in telecom,ranging,and molecular sensing.Integrated photonics,however,is usually considered not suitable for high-power applications mainly due to its small size which limits the energy storage capacity and,therefore,the output power.In the late 90s,to improve the beam quality and increase the stored energy,large-mode-area(LMA)fibers were introduced in which the optical mode area is substantially large.Such LMA fibers have transformed the high-power capability of fiber systems ever since.Introducing such an LMA technology at the chip-scale can play an equally disruptive role with high power signal generation from an integrated photonics system.To this end,in this work we demonstrate such a technology,and show a very high-power tunable laser with the help of a silicon photonics based LMA power amplifier.We show output power reaching 1.8 W over a tunability range of 60 nm,spanning from 1.83μm to 1.89μm,limited only by the seed laser.Such an integrated LMA device can be used to substantially increase the power of the existing integrated tunable lasers currently limited to a few tens of milliwatts.The power levels demonstrated here reach and surpass that of many benchtop systems which truly makes the silicon photonics based integrated LMA device poised towards mass deployment for high power applications without relying on benchtop systems.
基金supported by the European Space Agency(ESA)contract ESTEC CN 4000108280/12/NL/PAthe Defense Advanced Research Projects Agency(DARPA)contract W911NF-11-1-0202(QuASAR)+4 种基金the Swiss National Science Foundationsupported by the Air Force Office of Scientific Research,Air Force Material Command,under award FA9550-15-1-0099support from the ESA via contract ESTEC CN 4000105962/12/NL/PAsupport by the Marie Curie IIF Fellowshipsupport from the Hasler foundation and support from the‘EPFL Fellows’fellowship program co-funded by Marie Curie,FP7 Grant agreement no.291771。
文摘Self-referencing turns pulsed laser systems into self-referenced frequency combs.Such frequency combs allow counting of optical frequencies and have a wide range of applications.The required optical bandwidth to implement self-referencing is typically obtained via nonlinear broadening in optical fibers.Recent advances in the field of Kerr frequency combs have provided a path toward the development of compact frequency comb sources that provide broadband frequency combs,exhibit microwave repetition rates and are compatible with on-chip photonic integration.These devices have the potential to significantly expand the use of frequency combs.Yet to date,self-referencing of such Kerr frequency combs has only been attained by applying conventional,fiber-based broadening techniques.Here we demonstrate external broadening-free self-referencing of a Kerr frequency comb.An optical spectrum spanning two-thirds of an octave is directly synthesized from a continuous wave laser-driven silicon nitride microresonator using temporal dissipative Kerr soliton formation and soliton Cherenkov radiation.Using this coherent bandwidth and two continuous wave transfer lasers in a 2f–3f self-referencing scheme,we are able to detect the offset frequency of the soliton Kerr frequency comb.By stabilizing the repetition rate to a radio frequency reference,the self-referenced frequency comb is used to count and track the continuous wave pump laser’s frequency.This work demonstrates the principal ability of soliton Kerr frequency combs to provide microwave-to-optical clockworks on a chip.
基金the Defense Adva need Research Projects Agency(DARPA-DODOS)NIST-UDiversity of Maryland(70NANB10H193)National Institute of Standards and Technology(NIST-on-a-chip).A.R.and X.L.gratefully ack no wledge support un der the Cooperative Research Agreement between the University of Maryland and NIST-CNST,Award no.70NANB10H193.
文摘Microcombs-optical frequency combs generated in microresonators-have advanced tremendously in the past decade,and are advantageous for applications in frequency metrology,navigation,spectroscopy,telecommunications,and microwave photonics.Crucially,microcombs promise fully integrated miniaturized optical systems with unprecedented reductions in cost,size,weight,and power.However,the use of bulk free-space and fiber-optic comp on ents to process microcombs has restricted form factors to the table-top.Taking microcomb-based optical frequency synthesis around 1550 nm as our target application,here,we address this challenge by proposing an integrated photonics interposer architecture to replace discrete components by collecting,routing,and interfacing octave-wide microcomb-based optical signals between photonic chiplets and heterogeneously integrated devices.Experimentally,we con firm the requisite performa nee of the individual passive elements of the proposed interposer一octave-wide dichroics,multimode interferometers,and tunable ring filters,and implement the octave-spanning spectral filteri ng of a microcomb,central to the in terposer,using silicon n itride phot onics.Moreover,we show that the thick silicon nitride needed for bright dissipative Kerr soliton generation can be integrated with the comparatively thin silicon nitride interposer layer through octave-bandwidth adiabatic evanescent coupling,indicating a path towards future system-level consolidation.Fin ally,we numerically confirm the feasibility of operating the proposed in terposer synthesizer as a fully assembled system.Our interposer architecture addresses the immediate need for on-chip microcomb processing to successfully miniaturize microcomb systems and can be readily adapted to other metrology-grade applications based on optical atomic clocks and high-precision navigation and spectroscopy.
