Planar microlens with front-face angle: design, fabrication, and characterization

Handle URI:
http://hdl.handle.net/10754/618073
Title:
Planar microlens with front-face angle: design, fabrication, and characterization
Authors:
Hafiz, Md Abdullah Al ( 0000-0002-1257-5093 ) ; Michael, Aron; Kwok, Chee-Yee
Abstract:
This paper studies the effect of microlens front-face angle on the performance of an optical system consisting of a planar-graded refractive index (GRIN) lens pair facing each other separated by a free-space region. The planar silica microlens pairs are designed to facilitate low-loss optical signal propagation in the free-space region between the opposing optical waveguides. The planar lens is fabricated from a 38-μm-thick fluorine-doped silica layer on a silicon substrate. It has a parabolic refractive index profile in the vertical direction, which is achieved by controlled fluorine incorporation in the silica film to collimate the optical beam in the vertical direction. Horizontal beam collimation is achieved by incorporating a horizontal curvature at the front face of the lens defined by deep oxide etch. A generalized 3×3ABCDGH transformation matrix method has been derived to compute the coupling efficiency of such microlens pairs to take front-face angles that may be present due to fabrication variations or limitations and possible input/output optical fiber offset/tilt into considerations. Pairs of such planar GRIN lens with various free-space propagation distances between them ranging from 75 to 2500  μm and with front-face angles of 1.5 deg, 2 deg, and 4 deg have been fabricated and characterized. Beam propagation method simulations have been carried out to substantiate the theoretical and experimental results. The results indicate that the optical loss is reasonably low up to 1.5 deg of front-face angles and increases significantly with further increase in the front-face angle. Analysis shows that for a given system with specific microlens front-face angle, the optical loss can be significantly reduced by properly compensating the vertical position of the input and output fibers.
KAUST Department:
Mechanical Engineering Program
Citation:
Planar microlens with front-face angle: design, fabrication, and characterization 2016, 15 (3):035501 Journal of Micro/Nanolithography, MEMS, and MOEMS
Publisher:
SPIE-Intl Soc Optical Eng
Journal:
Journal of Micro/Nanolithography, MEMS, and MOEMS
Issue Date:
8-Jul-2016
DOI:
10.1117/1.JMM.15.3.035501
Type:
Article
ISSN:
1932-5150
Sponsors:
Authors would like to acknowledge the New South Wales Node of the Australian National Fabrication, where the work was performed.
Additional Links:
http://nanolithography.spiedigitallibrary.org/article.aspx?doi=10.1117/1.JMM.15.3.035501
Appears in Collections:
Articles

Full metadata record

DC FieldValue Language
dc.contributor.authorHafiz, Md Abdullah Alen
dc.contributor.authorMichael, Aronen
dc.contributor.authorKwok, Chee-Yeeen
dc.date.accessioned2016-08-09T11:04:18Z-
dc.date.available2016-08-09T11:04:18Z-
dc.date.issued2016-07-08-
dc.identifier.citationPlanar microlens with front-face angle: design, fabrication, and characterization 2016, 15 (3):035501 Journal of Micro/Nanolithography, MEMS, and MOEMSen
dc.identifier.issn1932-5150-
dc.identifier.doi10.1117/1.JMM.15.3.035501-
dc.identifier.urihttp://hdl.handle.net/10754/618073-
dc.description.abstractThis paper studies the effect of microlens front-face angle on the performance of an optical system consisting of a planar-graded refractive index (GRIN) lens pair facing each other separated by a free-space region. The planar silica microlens pairs are designed to facilitate low-loss optical signal propagation in the free-space region between the opposing optical waveguides. The planar lens is fabricated from a 38-μm-thick fluorine-doped silica layer on a silicon substrate. It has a parabolic refractive index profile in the vertical direction, which is achieved by controlled fluorine incorporation in the silica film to collimate the optical beam in the vertical direction. Horizontal beam collimation is achieved by incorporating a horizontal curvature at the front face of the lens defined by deep oxide etch. A generalized 3×3ABCDGH transformation matrix method has been derived to compute the coupling efficiency of such microlens pairs to take front-face angles that may be present due to fabrication variations or limitations and possible input/output optical fiber offset/tilt into considerations. Pairs of such planar GRIN lens with various free-space propagation distances between them ranging from 75 to 2500  μm and with front-face angles of 1.5 deg, 2 deg, and 4 deg have been fabricated and characterized. Beam propagation method simulations have been carried out to substantiate the theoretical and experimental results. The results indicate that the optical loss is reasonably low up to 1.5 deg of front-face angles and increases significantly with further increase in the front-face angle. Analysis shows that for a given system with specific microlens front-face angle, the optical loss can be significantly reduced by properly compensating the vertical position of the input and output fibers.en
dc.description.sponsorshipAuthors would like to acknowledge the New South Wales Node of the Australian National Fabrication, where the work was performed.en
dc.language.isoenen
dc.publisherSPIE-Intl Soc Optical Engen
dc.relation.urlhttp://nanolithography.spiedigitallibrary.org/article.aspx?doi=10.1117/1.JMM.15.3.035501en
dc.rightsArchived with thanks to Journal of Micro/Nanolithography, MEMS, and MOEMSen
dc.titlePlanar microlens with front-face angle: design, fabrication, and characterizationen
dc.typeArticleen
dc.contributor.departmentMechanical Engineering Programen
dc.identifier.journalJournal of Micro/Nanolithography, MEMS, and MOEMSen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionThe University of New South Wales, School of Electrical Engineering and Telecommunication, Anzac Parade, Kensington, New South Wales 2052, Australiaen
dc.contributor.institutionThe University of New South Wales, School of Electrical Engineering and Telecommunication, Anzac Parade, Kensington, New South Wales 2052, Australiaen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorHafiz, Md Abdullah Alen
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.