Wafer-level mass production of photonic integrated circuits(PIC)has become a technological mainstay in the field of optics and photonics,enabling many novel and disrupting a wide range of existing applications.However...Wafer-level mass production of photonic integrated circuits(PIC)has become a technological mainstay in the field of optics and photonics,enabling many novel and disrupting a wide range of existing applications.However,scalable photonic packaging and system assembly still represents a major challenge that often hinders commercial adoption of PIC-based solutions.Specifically,chip-to-chip and fiber-to-chip connections often rely on so-called active alignment techniques,where the coupling efficiency is continuously measured and optimized during the assembly process.This unavoidably leads to technically complex assembly processes and high cost,thereby eliminating most of the inherent scalability advantages of PIC-based solutions.In this paper,we demonstrate that 3D-printed facet-attached microlenses(FaML)can overcome this problem by opening an attractive path towards highly scalable photonic system assembly,relying entirely on passive assembly techniques based on industry-standard machine vision and/or simple mechanical stops.FaML can be printed with high precision to the facets of optical components using multi-photon lithography,thereby offering the possibility to shape the emitted beams by freely designed refractive or reflective surfaces.Specifically,the emitted beams can be collimated to a comparatively large diameter that is independent of the device-specific mode fields,thereby relaxing both axial and lateral alignment tolerances.Moreover,the FaML concept allows to insert discrete optical elements such as optical isolators into the free-space beam paths between PIC facets.We show the viability and the versatility of the scheme in a series of selected experiments of high technical relevance,comprising pluggable fiber-chip interfaces,the combination of PIC with discrete micro-optical elements such as polarization beam splitters,as well as coupling with ultra-low back-reflection based on non-planar beam paths that only comprise tilted optical surfaces.Based on our results,we believe that the FaML concept opens an attractive path towards novel PIC-based system architectures that combine the distinct advantages of different photonic integration platforms.展开更多
基金the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy via the Excellence Cluster 3D Matter Made to Order(EXC-2082/1-390761711)the Collaborative Research Center WavePhenomena(CRC 1173)+4 种基金by the Bundesministerium für Bildung und Forschung(BMBF)via the projects PRIMA(#13N14630),DiFeMiS(#16ES0948)which is part of the programme“Forschungslabore Mikroelektronik Deutschland(ForLab),and Open6GHub(#16KISK010)by the European Research Council(ERC Consolidator Grant‘TeraSHAPE’#773248),by the H2020 Photonic Packaging Pilot Line PIXAPP(#731954)by the Alfried Krupp von Bohlen und Halbach Foundation,and by the Karlsruhe School of Optics and Photonics(KSOP).
文摘Wafer-level mass production of photonic integrated circuits(PIC)has become a technological mainstay in the field of optics and photonics,enabling many novel and disrupting a wide range of existing applications.However,scalable photonic packaging and system assembly still represents a major challenge that often hinders commercial adoption of PIC-based solutions.Specifically,chip-to-chip and fiber-to-chip connections often rely on so-called active alignment techniques,where the coupling efficiency is continuously measured and optimized during the assembly process.This unavoidably leads to technically complex assembly processes and high cost,thereby eliminating most of the inherent scalability advantages of PIC-based solutions.In this paper,we demonstrate that 3D-printed facet-attached microlenses(FaML)can overcome this problem by opening an attractive path towards highly scalable photonic system assembly,relying entirely on passive assembly techniques based on industry-standard machine vision and/or simple mechanical stops.FaML can be printed with high precision to the facets of optical components using multi-photon lithography,thereby offering the possibility to shape the emitted beams by freely designed refractive or reflective surfaces.Specifically,the emitted beams can be collimated to a comparatively large diameter that is independent of the device-specific mode fields,thereby relaxing both axial and lateral alignment tolerances.Moreover,the FaML concept allows to insert discrete optical elements such as optical isolators into the free-space beam paths between PIC facets.We show the viability and the versatility of the scheme in a series of selected experiments of high technical relevance,comprising pluggable fiber-chip interfaces,the combination of PIC with discrete micro-optical elements such as polarization beam splitters,as well as coupling with ultra-low back-reflection based on non-planar beam paths that only comprise tilted optical surfaces.Based on our results,we believe that the FaML concept opens an attractive path towards novel PIC-based system architectures that combine the distinct advantages of different photonic integration platforms.
