Highly efficient tunable optical filter based on liquid crystal micro-ring resonator with large free spectral range

doi:10.1007/s12200-015-0483-1

Front. Optoelectron.

2016, Vol. 9

Issue (1) : 112-120 https://doi.org/10.1007/s12200-015-0483-1

RESEARCH ARTICLE

Highly efficient tunable optical filter based on liquid crystal micro-ring resonator with large free spectral range

Jing DAI^1,²,Minming ZHANG^1,^2,^*(

),Feiya ZHOU^1,²,Deming LIU^1,²

1. School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
2. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China

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Abstract

A highly efficient tunable optical filter of liquid crystal (LC) optical micro-ring resonator (MRR) was proposed. The 4-μm-radius ring consists of a silicon-on-insulator (SOI) asymmetric bent slot waveguide with a LC cladding. The geometry of the slot waveguide resulted in the strong electro-optic effect of the LC, and therefore induced an increase in effective refractive index by 0.0720 for the quasi-TE mode light in the slot-waveguide. The ultra-wide tuning range (56.0 nm) and large free spectral range (FSR) (~28.0 nm) of the optical filters enabled wavelength reconfigurable multiplexing devices with a drive voltage of only 5 V. The influences of parameters, such as the slot width, total width of Si rails and slot shift on the device’s performance, were analyzed and the optimal design was given. Moreover, the influence of fabrication tolerances and the loss of device were both investigated. Compared with state-of-the-art tunable MRRs, the proposed electrically tunable micro-ring resonator owns the excellent features of wider tuning ranges, larger FSRs and ultralow voltages.

Keywords integrated optics devices liquid crystals micro-ring resonator slot waveguide wavelength tuning

Corresponding Author(s): Minming ZHANG

Online First Date: 30 June 2015 Issue Date: 18 March 2016

Cite this article:

Jing DAI,Minming ZHANG,Feiya ZHOU, et al. Highly efficient tunable optical filter based on liquid crystal micro-ring resonator with large free spectral range[J]. Front. Optoelectron., 2016, 9(1): 112-120.

URL:

https://academic.hep.com.cn/foe/EN/10.1007/s12200-015-0483-1
https://academic.hep.com.cn/foe/EN/Y2016/V9/I1/112

Fig.1 Schematic top view of the tunable optical filter based on a silicon slot-waveguide micro-resonator infiltrated with LC cladding

Fig.2 Schematic cross-sectional view of the SOI strip-loaded bent slot waveguide with LC cladding (where g is the slot width, x represents the slot shift, which is defined as the distance (in nm) from the center of the waveguide to the center of the slot, W (W = w_l + w_r) is the total width of two Si rails in the slot waveguide, H and h are the height of the Si rails and Si slab, respectively)

Fig.3 (a) Two states of LC molecules director for slot waveguides: (1, U = 0) no external voltage is applied to the slot waveguide, the LC molecules align parallel to z-direction; (2, U>0) a large external voltage is applied to the slot waveguide, the LC will partly realign along the x-direction; (b) calculated refractive index n_LC(θ) on the voltage for the SOI LC slot waveguide (g = 100 nm)

Fig.4 Comparison of different SOI slot- and strip-waveguides with LC cladding. (a) Transverse E-field amplitude of the quasi-TE optical mode field for slot waveguide; (b) transverse E-field amplitude of the TE₀ optical mode for strip waveguide; (c) vertical E-field amplitude of the TM₀ optical mode for strip waveguide

Fig.5 Relationship between the resonant wavelength and the voltage: for SOI slot LC micro-ring resonator with quasi-TE mode (red curve); for LC MRR based on strip waveguide with TE mode (black curve) and TM mode (blue curve) [9]

Fig.6 Tuning range of a silicon single-slot waveguide LC microring (R = 4 μm, non-shift) as a function of the slot width g at different over widths W = 400, 480 and 600 nm

Fig.7 Tuning range of resonance wavelength of a silicon single-slot waveguide LC micro-ring (R = 4 μm) as a function of the slot shift x (a) at different overall Si rail widths W = 400, 480 and 600 nm with g = 100 nm; and (b) at different slot widths g = 60, 100 and140 nm with W = 400 nm

Fig.8 Free spectrum range of a silicon single-slot waveguide LC micro-ring (R = 4 μm) as a function of the slot shift x (a) at different overall Si rail widths W = 400, 480 and 600 nm with g = 100 nm; and (b) at different slot widths g = 60, 100 and 140 nm with W = 400 nm

Fig.9 (a) Tuning range of wavelength as a function of the total Si strips width W (g = 100 nm, R = 4 μm and x = 60 nm); (b) wavelength tuning range for a slot microrings as a function of non vertical sidewall tilting angle θ (W = 400 nm, g = 100 nm, R = 4 μm and x = 60 nm)

Fig.10 Electric intensity |E|² of the quasi-TE optical mode field for the bent LC slot-waveguide with slot shift position x = 60 nm (R = 4 μm, W = 400 nm and g = 100 nm)

1	Selvaraja S K, Jaenen P, Bogaerts W, Van Thourhout D, Dumon P, Baets R. Fabrication of photonic wire and crystal circuits in silicon-on-insulator using 193-nm optical lithography. Journal of Lightwave Technology, 2009, 27(18): 4076–4083 https://doi.org/10.1109/JLT.2009.2022282
2	Dumon P, Bogaerts W, Wiaux V, Wouters J, Beckx S, Van Campenhout J, Taillaert D, Luysaert B, Bienstman P, Van Thourhout D, Baets R. Low-loss SOI photonic wires and ring resonators fabricated with deep UV lithography. IEEE Photonics Technology Letters, 2004, 16(5): 1328–1330 https://doi.org/10.1109/LPT.2004.826025
3	Basch E B, Egorov R, Gringeri S, Elby S. Architectural tradeoffs for reconfigurable dense wavelength-division multiplexing systems. IEEE Journal of Selected Topics in Quantum Electronics, 2006, 12(4): 615–626 https://doi.org/10.1109/JSTQE.2006.876167
4	Ng H, Wang M R, Li D, Wang X, Martinez J, Panepucci R R, Pathak K. 1×4 wavelength reconfigurable photonic switch using thermally tuned microring resonators fabricated on silicon substrate. IEEE Photonics Technology Letters, 2007, 19(9): 704–706 https://doi.org/10.1109/LPT.2007.895420
5	Yalcin A, Popat K C, Aldridge J C, Desai T A, Hryniewicz J, Chbouki N, Little B E, King O, Van V, Chu S, Gill D, Anthes-Washburn M, Unlu M S, Goldberg B B. Optical sensing of biomolecules using microring resonators. IEEE Journal of Selected Topics in Quantum Electronics, 2006, 12(1): 148–155 https://doi.org/10.1109/JSTQE.2005.863003
6	Dong P, Qian W, Liang H, Shafiiha R, Feng N, Feng D, Zheng X, Krishnamoorthy A V, Asghari M. Low power and compact reconfigurable multiplexing devices based on silicon microring resonators. Optics Express, 2010, 18(10): 9852–9858 https://doi.org/10.1364/OE.18.009852 pmid: 20588834
7	Guarino A, Poberaj G, Rezzonico D, Degl’innocenti R, Günter P. Electro-optically tunable microring resonators in lithium niobate. Nature Photonics, 2007, 1(7): 407–410 https://doi.org/10.1038/nphoton.2007.93
8	Liu A, Liao L, Rubin D, Nguyen H, Ciftcioglu B, Chetrit Y, Izhaky N, Paniccia M. High-speed optical modulation based on carrier depletion in a silicon waveguide. Optics Express, 2007, 15(2): 660–668 https://doi.org/10.1364/OE.15.000660 pmid: 19532289
9	Dong P, Qian W, Liang H, Shafiiha R, Feng D, Li G, Cunningham J E, Krishnamoorthy A V, Asghari M. Thermally tunable silicon racetrack resonators with ultralow tuning power. Optics Express, 2010, 18(19): 20298–20304 https://doi.org/10.1364/OE.18.020298 pmid: 20940921
10	Nishihara H, Haruna M, Suhara T. Optical Integrated Circuit. New York: McGraw-Hill1985, 36–44
11	Soref R A, Bennett B R. Electrooptical effects in silicon. IEEE Journal of Quantum Electronics, 1987, 23(1): 123–129 https://doi.org/10.1109/JQE.1987.1073206
12	Maune B, Lawson R, Gunn C, Scherer A, Dalton L. Electrically tunable ring resonators incorporating nematic liquid crystals as cladding layers. Applied Physics Letters, 2003, 83(23): 4689–4691 https://doi.org/10.1063/1.1630370
13	Falco A D, Assanto G. Tunable wavelength-selective add–drop in liquid crystals on a silicon microresonator. Optics Communications, 2007, 279(1): 210–213 https://doi.org/10.1016/j.optcom.2007.06.063
14	De Cort W, Beeckman J, James R, Fernandez F A, Baets R, Neyts K. Tuning silicon-on-insulator ring resonators with in-plane switching liquid crystals. Journal of the Optical Society of America B, Optical Physics, 2011, 28(1): 79–85 https://doi.org/10.1364/JOSAB.28.000079
15	De Cort W, Beeckman J, Claes T, Neyts K, Baets R. Wide tuning of silicon-on-insulator ring resonators with a liquid crystal cladding. Optics Letters, 2011, 36(19): 3876–3878 https://doi.org/10.1364/OL.36.003876 pmid: 21964127
16	Almeida V R, Xu Q, Barrios C A, Lipson M. Guiding and confining light in void nanostructure. Optics Letters, 2004, 29(11): 1209–1211 https://doi.org/10.1364/OL.29.001209 pmid: 15209249
17	Anderson P A, Schmidt B S, Lipson M. High confinement in silicon slot waveguides with sharp bends. Optics Express, 2006, 14(20): 9197–9202 https://doi.org/10.1364/OE.14.009197 pmid: 19529300
18	Kargar A, Chao C. Design and optimization of waveguide sensitivity in slot microring sensors. Journal of the Optical Society of America A, Optics, Image Science, and Vision, 2011, 28(4): 596–603 https://doi.org/10.1364/JOSAA.28.000596 pmid: 21478955
19	Pfeifle J, Alloatti L, Freude W, Leuthold J, Koos C. Silicon-organic hybrid phase shifter based on a slot waveguide with a liquid-crystal cladding. Optics Express, 2012, 20(14): 15359–15376 https://doi.org/10.1364/OE.20.015359 pmid: 22772233
20	Barrios C A, Lipson M. Electrically driven silicon resonant light emitting device based on slot-waveguide. Optics Express, 2005, 13(25): 10092–10101 https://doi.org/10.1364/OPEX.13.010092 pmid: 19503222
21	Gould M, Baehr-Jones T, Ding R, Huang S, Luo J, Jen A K, Fedeli J M, Fournier M, Hochberg M. Silicon-polymer hybrid slot waveguide ring-resonator modulator. Optics Express, 2011, 19(5): 3952–3961 https://doi.org/10.1364/OE.19.003952 pmid: 21369221
22	Desmet H, Neyts K, Baets R. Liquid crystal orientation on patterns etched in silicon on insulator. Integrated Optics, Silicon Photonics, and Photonic Integrated Circuits, 2006, 6183: 61831Z
23	Ge Z, Wu T X, Lu R, Zhu X, Hong Q, Wu S. Comprehensive three-dimensional dynamic modeling of liquid crystal devices using finite element method. Journal of Display Technology, 2005, 1(2): 194–206 https://doi.org/10.1109/JDT.2005.858885
24	Fallahkhair A B, Li K S, Murphy T E. Vector finite difference modesolver for anisotropic dielectric waveguides. Journal of Lightwave Technology, 2008, 26(11): 1423–1431 https://doi.org/10.1109/JLT.2008.923643
25	Dell’Olio F, Passaro V M. Optical sensing by optimized silicon slot waveguides. Optics Express, 2007, 15(8): 4977–4993 https://doi.org/10.1364/OE.15.004977 pmid: 19532747
26	Donisi D, Bellini B, Beccherelli R, Asquini R, Gilardi G, Trotta M, d’ Alessandro A. A switchable liquid-crystal optical channel waveguide on silicon. IEEE Journal of Quantum Electronics, 2010, 46(5): 762–768 https://doi.org/10.1109/JQE.2009.2038241

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