TY - GEN

T1 - Applying sacrificial substrate technology to miniaturized precision optical thin-film coatings

AU - Rüsseler, Anna Karoline

AU - Carstens, Florian

AU - Jensen, Lars

AU - Bengsch, Sebastian

AU - Ristau, Detlev

N1 - Funding Information: The authors would like to thank the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) for funding this work under Germany’s Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453).

PY - 2021/9/12

Y1 - 2021/9/12

N2 - Hybrid integrated photonics open up new application perspectives due to compact size and the shift to cost-efficient components. Therefore, integration of optical and electro-optical functionalities into photonic chips has recently attracted great interest. Research has been directed towards miniaturization of demanding spectral transfer properties for individual applications.1 However, it remains challenging to implement highly complex transmission and reflection characteristics with few additional process steps. In this contribution, we report on our advancement in the field of optical thin-film coating fabrication, which enables a manufacturing process comparable to die assembly in electronics. We have combined a sacrificial-substrate approach with the production of miniaturized optical thin-film coatings by ion-beam sputtering. The concept is applicable to high precision coatings with more than 130 individual layers and adding up to over 26µm total film thickness. Segmentation down to sizes of 25µmx25µm pieces is realized by laser cutting of the coating. By completely removing the substrate afterwards, we achieve a freestanding thin-film and thus minimized thickness. Our measurements indicate no general performance loss compared to coatings on glass substrates. Additionally, the substrates refractive index and absorption do not have to be considered in the multilayer-coating design. Therefore, the design can be optimized and matched to the refractive index of specific waveguides on the chip. Furthermore, we demonstrate the compatibility to releasable transfer tape. With this, we aim for enabling a high-volume feed of miniaturized thin-film filters to an automated assembly process.

AB - Hybrid integrated photonics open up new application perspectives due to compact size and the shift to cost-efficient components. Therefore, integration of optical and electro-optical functionalities into photonic chips has recently attracted great interest. Research has been directed towards miniaturization of demanding spectral transfer properties for individual applications.1 However, it remains challenging to implement highly complex transmission and reflection characteristics with few additional process steps. In this contribution, we report on our advancement in the field of optical thin-film coating fabrication, which enables a manufacturing process comparable to die assembly in electronics. We have combined a sacrificial-substrate approach with the production of miniaturized optical thin-film coatings by ion-beam sputtering. The concept is applicable to high precision coatings with more than 130 individual layers and adding up to over 26µm total film thickness. Segmentation down to sizes of 25µmx25µm pieces is realized by laser cutting of the coating. By completely removing the substrate afterwards, we achieve a freestanding thin-film and thus minimized thickness. Our measurements indicate no general performance loss compared to coatings on glass substrates. Additionally, the substrates refractive index and absorption do not have to be considered in the multilayer-coating design. Therefore, the design can be optimized and matched to the refractive index of specific waveguides on the chip. Furthermore, we demonstrate the compatibility to releasable transfer tape. With this, we aim for enabling a high-volume feed of miniaturized thin-film filters to an automated assembly process.

KW - Automated assembly

KW - Broad band monitor

KW - Hybrid integrated photonics

KW - Ion beam sputtering

KW - Miniaturized thin-film coatings

KW - PhoenixD

KW - Sacrificial substrate

KW - Substrate-free thin-film filters

UR - http://www.scopus.com/inward/record.url?scp=85118916953&partnerID=8YFLogxK

U2 - 10.1117/12.2597003

DO - 10.1117/12.2597003

M3 - Conference contribution

AN - SCOPUS:85118916953

T3 - Proceedings of SPIE - The International Society for Optical Engineering

BT - Advances in Optical Thin Films VII

A2 - Lequime, Michel

A2 - Ristau, Detlev

PB - SPIE

T2 - Advances in Optical Thin Films VII 2021

Y2 - 13 September 2021 through 17 September 2021

ER -