Non-diffracting beam generated from a photonic integrated circuit based axicon-like lens

Maharjan, R., Bohora, S., Bhattarai, P., Crowe, I., Curry, R. J., Hogg, R. , Childs, D. and Dhakal, A. (2021) Non-diffracting beam generated from a photonic integrated circuit based axicon-like lens. Optics Express, 29(7), pp. 10480-10490. (doi: 10.1364/OE.419618) (PMID:33820182)

Abstract

We demonstrate an on-chip silicon-on-insulator (SOI) device to generate a non-diffracting beam of ≈850 µm length from a diffractive axicon-like lens etched using a low resolution (200 nm feature size, 250 nm gap) deep-ultraviolet lithographic fabrication. The device consists of circular gratings with seven stages of 1x2 multimode interferometers. We present a technique to apodize the gratings azimuthally by breaking up the circles into arcs which successfully increased the penetration depth in the gratings from ≈5 µm to ≈60 µm. We characterize the device’s performance by coupling 1300±50 nm swept source laser in to the chip from the axicon and measuring the out-coupled light from a grating coupler. Further, we also present the implementation of balanced homodyne detection method for the spectral characterization of the device and show that the position of the output lobe of the axicon does not change significantly with wavelength.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Childs, Dr David and Hogg, Professor Richard
• Authors: Maharjan, R., Bohora, S., Bhattarai, P., Crowe, I., Curry, R. J., Hogg, R., Childs, D., and Dhakal, A.
• College/School: College of Science and Engineering > School of Engineering; College of Science and Engineering > School of Engineering > James Watt Nanofabrication Centre
• Journal Name: Optics Express
• Publisher: Optical Society of America
• ISSN: 1094-4087
• ISSN (Online): 1094-4087
• Published Online: 18 March 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Optics Express 29(7): 10480-10490
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
300623		Integrated 'on-chip' optical coherence tomography (OCT) system for point of care imaging diagnostics	David Childs	Engineering and Physical Sciences Research Council (EPSRC)	EP/R014418/1-R121940	ENG - Electronics & Nanoscale Engineering