[Illinois] Engineering the Mode Coupling in Microrings for Laser and Sensor Applications

By Lynford Goddard

University of Illinois at Urbana-Champaign

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The integrated microring Bragg reflector forms the basis of a new family of compact reflective photonic devices. The buildup of field strength in the high quality factor ring resonator configuration yields multiple reflection encounters with the same set of gratings. This enables high reflectivity with only a few pairs of low index contrast first order gratings and makes possible compact passive narrow band laser end mirrors for wavelength locking. Second order gratings can be engineered in an active material to selectively couple all but one of the counter-propagating modes of the ring to radiation modes and thereby create a single wavelength ring laser. For sensing applications, the gratings can be replaced with gold epitopes to form a hybrid whispering gallery mode/plasmonic chain ring resonator. The field localization properties near the epitopes and thus the detection sensitivity change drastically as the radius of the epitopes is varied due to the existence of distinct coupling regions of the hybrid resonator.


Dr. Lynford Goddard received the Ph.D. in physics (thesis: 1.5m GaInNAsSb/GaAs lasers) from Stanford in 2005. He conducted postdoctoral research at LLNL on photonic integrated circuits and sensors. He joined the University of Illinois faculty in 2007 and is currently an Associate Professor of Electrical and Computer Engineering. His group fabricates, tests, and models photonic sensors, circuits, and instrumentation, develops novel device processing techniques, and applies quantitative phase microscopy for semiconductor wafer metrology. He was an IEEE Photonics Journal Associate Editor (2009-2014) and currently serves on its Advisory Board. He received the AAAS Early Career Public Engagement Award in 2011 and the PECASE award in 2010. Dr. Goddard is co-author of over 160 publications and 6 patents.

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Researchers should cite this work as follows:

  • Lynford Goddard (2016), "[Illinois] Engineering the Mode Coupling in Microrings for Laser and Sensor Applications," http://nanohub.org/resources/23591.

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University of Illinois at Urbana-Champaign