Hybrid Photonic Chip Interferometer for Embedded Metrology

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Embedded metrology is the provision of metrology on the manufacturing platform, enabling measurement without the removal of the work piece. Providing closer integration of metrology upon the manufacturing platform can lead to the better control and increased throughput. In this work we present the development of a high precision hybrid optical chip interferometer metrology device. The complete metrology sensor system is structured into two parts; optical chip and optical probe. The hybrid optical chip interferometer is based on a silica-on-silicon etched integrated-optic motherboard containing waveguide structures and evanescent couplers. Upon the motherboard, electro-optic components such as photodiodes and a semiconductor gain block are mounted and bonded to provide the required functionality. The key structure in the device is a tunable laser module based upon an external-cavity diode laser (ECDL). Within the cavity is a multi-layer thin film filter which is rotated to select the longitudinal mode at which the laser operates. An optical probe, which uses a blazed diffracting grating and collimating objective lens, focuses light of different wavelengths laterally over the measurand. Incident laser light is then tuned in wavelength time to effectively sweep an-optical stylus-over the surface. Wavelength scanning and rapid phase shifting can then retrieve the path length change and thus the surface height. We give an overview of the overall design of the final hybrid photonic chip interferometer, constituent components, device integration and packaging as well as experimental test results from the current version now under evaluation.

Original languageEnglish
Title of host publicationIntegrated Optics
Subtitle of host publicationDevices, Materials, and Technologies XVIII
EditorsJean Emmanuel Broquin, Gualtiero Nunzi Conti
Number of pages10
ISBN (Print)9780819499011
Publication statusPublished - 8 Mar 2014
EventSPIE OPTO - San Francisco, United States
Duration: 1 Feb 20146 Feb 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSPIE OPTO
Country/TerritoryUnited States
CitySan Francisco


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