of 13
Design and characterization of
w
hispering-gallery spiral waveguides
Tong Chen, Hansuek Lee, and Kerry J. Vahala
T. J. Watson Laboratory of Applied Physics, California Institute of Technology,
Pasadena, California, 91125, USA
va
hala@caltech.edu
Abstract:
W
hispering gallery delay lines have demonstrated record
propagation length on a silicon chip and can provide a way to transfer
certain applications of optical fiber to wafer-based systems. Their design
and fabrication requires careful control of waveguide curvature and etching
conditions to minimize connection losses between elements of the delay
line. Moreover, loss characterization based on optical backscatter requires
normalization to account for the impact of curvature on backscatter rate. In
this paper we provide details on design of Archimedean whispering-gallery
spiral waveguides, their coupling into cascaded structures, as well as optical
loss characterization by optical backscatter reflectometry.
© 2014 Optical Society of America
OCIS codes:
(230.7390) Waveguides, planar; (220.0220) Optical design and fabrication.
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1.
Introduction
R
ecently, a method of fabricating ultra-high-Q resonators in silica on silicon wafers was re-
ported [1]. Because the processing of these structures uses conventional lithography and etch-
ing, there is a high level of size control possible. As an important extension of the process,
#200514 - $15.00 USD
Received 5 Nov 2013; revised 27 Jan 2014; accepted 10 Feb 2014; published 27 Feb 2014
(C)
2014
OSA
10
March
2014
| Vol.
22,
No.
5 | DOI:10.1364/OE.22.005196
| OPTICS
EXPRESS
5196