In-Fiber Butt-Coupled Spherical Microcavity With Whispering Gallery Mode and Fabry-Perot Resonances

An integrated in-fiber coupling configuration for simultaneously exciting whispering gallery mode (WGM) and Fabry-Perot (FP) resonances in one cavity is proposed and demonstrated experimentally. The WGMs traveling circularly in both clockwise and counter-clockwise directions are simultaneously excit...

Full description

Saved in:
Bibliographic Details
Published in:IEEE photonics technology letters 2021-06, Vol.33 (11), p.553-556
Main Authors: Shi, Leilei, Wang, Qianqian, Jiang, Lidan, Gao, Qirui, Zhu, Tao
Format: Article
Language:English
Subjects:
Asymmetry
Configurations
Coupling
Couplings
Electromagnetic wave filters
Fabry-Perot
Functional materials
Holes
Micromachining
Optical fiber couplers
Optical fiber devices
Optical fiber sensors
Optical fibers
Optical interferometry
Optical resonators
Phase matching
Refractive index
Silicon
Standing waves
Switches
whispering gallery modes
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:An integrated in-fiber coupling configuration for simultaneously exciting whispering gallery mode (WGM) and Fabry-Perot (FP) resonances in one cavity is proposed and demonstrated experimentally. The WGMs traveling circularly in both clockwise and counter-clockwise directions are simultaneously excited by perpendicularly injecting the light from the single-mode-fiber (SMF) core into a polymeric microsphere embedded in the femtosecond laser micromachined coupling structure. While the standing wave between the two axial interfaces of the microsphere and its external media results in a spherical FP resonator, meaning that the WGM and the FP resonances coexist in the same spherical cavity. The superposition of WGM and FP resonances results in asymmetric Fano-like lineshape, which is of high importance for optical fiber sensors, filters, and switches due to its sharp slope around the resonant wavelength. Experimental results show that asymmetric spectral lineshape can be achieved even as the spatial coupling gap is larger than the wavelength, indicating that the proposed coupler has higher fabrication tolerance than the evanescent field-based coupling configuration. Such an integrated coupling configuration provides an effective method for the coupling between the optical fiber and WGM cavities made of any functional material by liberating them from the phase-matching condition and enriching the functionality by importing other resonance into the same cavity.
ISSN:1041-1135
1941-0174
DOI:10.1109/LPT.2021.3075970