Abstract
We present microfluidic multimode fiber Mach–Zehnder interferometers (MMF-MZIs), suitable for refractive index (RI) measurement. The compact and low-cost all-fiber MMF-MZIs were made by forming two coupling points in series at a localized short section (about 1–5 cm) of a multimode optical fiber, using an electric-arc system, thus allowing the excitation and recombination of core and cladding modes. The MMF-MZIs have been integrated with a home-made microfluidic chip, used as a high sensitivity RI sensor to ascertain the surrounding RI variations. This type of microfluidic lab-on-a-chip MZI-based sensor was shown to be effective in sensing very small quantities of samples and its transmitted light signal could easily be measured. The spectra of all MMF-MZIs were Fourier transformed to obtain and the spatial frequency spectra. The MMF-MZIs exhibited many dominant spatial frequencies for all interferometer lengths and interference was mainly constructed by the core mode and dominant lower order cladding modes when the sensing length was 2–5 cm as well as distributed by the core mode and dominant higher order cladding modes when the sensing length was 1 cm. The transmitted spectra of the MMF-MZIs exhibited various sinusoidal-like interference fringes’ amplitudes and peaks changed differently by immersing the MMF-MZIs in different concentrations of sucrose solutions. The microfluidic MMF-MZI sensors have a high resolution of 3.1 × 10−5 to 7.5 × 10−5 RIU and a high sensitivity of 160–347 dBm/RIU within RI range from 1.333 to 1.370.
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References
Bergland GD (1969) A guided tour of the fast Fourier transform. IEEE Spectrum 6:41–52
Bhatia V (1999) Applications of long-period gratings to single and multi-parameter sensing. Opt Expr 4:457–466
Chau LK et al (2006) Fiber-optic chemical and biochemical probes based on localized surface plasmon resonance. Sensor Actuat B Chem 113:100–105
Chen C-H et al (2010a) Multimode fiber Mach-Zehnder interferometer for measurement of refractive index. Proc IEEE Sensors 61–64
Chen C-H et al (2010b) A multi-D-shaped optical fiber for refractive index sensing. Sensors 10:4794–4804
Chen C-H et al (2010c) Novel D-type fiber optic localized plasmon resonance sensor realized by femtosecond laser engraving. J Laser Micro Nanoeng 5:1–5
Chen C-H et al (2013) Fabrication quality analysis of a fiber optic refractive index sensor created by CO2 laser machining. Sensors 13:4067–4087
Chen C-H et al (2014) Optical coupling structures of fiber-optic Mach-Zehnder interferometers using CO2 laser irradiation. Intl J Antennas Propag 2014:1–9
Cheng SF, Chau LK (2003) Colloidal gold-modified optical fiber for chemical and biochemical sensing. Analytical Chemistry 75:16–21
Chin LK et al (2008) An on-chip liquid tunable grating using multiphase droplet microfluidics. Applied Physics Letters 93:164107-1–164107-3
Choi HY et al (2007) All-fiber Mach-Zehnder type interferometers formed in photonic crystal fiber. Opt Expr 15:5711–5720
Choi HY et al (2010) Cross-talk free and ultra-compact fiber optic sensor for simultaneous measurement of temperature and refractive index. Opt Expr 18:141–149
Hung C-T et al (2009) A novel design of grooved fibers for fiber-optic localized plasmon resonance biosensors. Sensors 9:6456–6470
Hwang T-C (1994) Experiments in physical chemistry (in traditional Chinese) Gaulih Taipei
James SW, Tatam RP (2003) Optical fiber long-period grating sensors: characteristics and application. Measurement Science & Technology 14:R46–R61
Jha R et al (2009) Refractometry based on a photonic crystal fiber interferometer. Optics Letters 34:617–619
Jung Y et al (2008) Ultracompact in-line broadband Mach-Zehnder interferometer using a composite leaky hollow-optical-fiber waveguide. Optics Letters 33:2934–2936
Kersey AD (1996) A review of recent developments in fiber optic sensor technology. Opt Fiber Technol 2:291–317
Li B et al (2011) Ultra-abrupt tapered fiber Mach-Zehnder interferometer sensors. Sensors 11:5729–5739
Lu P et al (2009) Tapered fiber Mach-Zehnder interferometer for simultaneous measurement of refractive index and temperature. Applied Physics Letters 94:131110-1–131110-3
Nunes PS et al (2010) Refractive index sensor based on a 1D photonic crystal in a microfluidic channel. Sensors 10:2348–2358
Patrick H, Kersey A (1998) Analysis of the response of long period fiber gratings to external index of refraction. Journal of Lightwave Technology 16:1606–1612
Rindorf L, Bang O (2008) Sensitivity of photonic crystal fiber grating sensors: biosensing, refractive index, strain, and temperature sensing. J Opt Soc Am B 25:310–324
Sparks D et al (2003) Measurement of density and chemical concentration using a microfluidic chip. Lab on a Chip 3:19–21
Stone HA, Kim S (2001) Microfluidics: basic issues, applications and challenges. Am Inst Chem Eng J 47:1250–1254
Tang J-L, Wang J-N (2008) Chemical sensing sensitivity of long-period grating sensor enhanced by colloidal gold nanoparticles. Sensors 8:171–184
Tian Z et al (2008a) Refractive index sensing with Mach-Zehnder interferometer based on concatenating two single mode fiber tapers. IEEE Photon Technol Lett 20:626–628
Tian Z et al (2008b) Refractive index sensor based on an abrupt taper Michelson interferometer in a single mode fiber. Optics Letters 33:1105–1107
Tripathi SM et al (2008) Side-Polished optical fiber grating-based refractive index sensors utilizing the pure surface plasmon polariton. Journal of Lightwave Technology 26:1980–1985
Villatoro J et al (2007) Simple all-microstructured-optical-fiber interferometer built via fusion splicing. Opt Expr 15:1491–1496
Wang J-N (2011) A microfluidic long-period fiber grating sensor platform for chloride ion concentration measurement. Sensors 11:8550–8568
Wang J-N, Luo C-Y (2012) Long-period fiber grating sensors for the measurement of liquid level and fluid-flow velocity. Sensors 12:4578–4593
Wang J-N, Tang J-L (2010) Feasibility of fiber Bragg grating and long-period fiber grating sensors under different environmental conditions. Sensors 10:10105–10127
Wang J-N, Tang J-L (2012) Photonic crystal fiber Mach-Zehnder interferometer for refractive index sensing. Sensors 12:2989–2995
Wang Y et al (2010) Fiber in-line Mach-Zehnder interferometer fabricated by femtosecond laser micromachining for refractive index measurement with high sensitivity. J Opt Soc Am B 27:370–374
Whitesides GM (2006) The origins and the future of microfluidics. Nature 442:368–373
Xia TH et al (2010) Fiber-Optic refractive-index sensors based on transmissive and reflective thin-core fiber modal interferometers. Optics Communication 283:2136–2139
Zhao L et al (2011) A high-quality Mach-Zehnder interferometer fiber sensor by femtosecond laser one-step processing. Sensors 15:54–61
Zhu T et al (2012) In-Line fiber optic interferometeric sensors in single-mode fibers. Sensors 12:10430–10449
Acknowledgments
The support for this study provided by the Ministry of Science and Technology (Taiwan) through Grant Numbers: MOST-101-2221-E-020-010-MY3, MOST 104-2221-E-224-054, MOST-101-2120-M-194-001-CC2, MOST-102-2221-E-224-065-MY2, MOST 103-2811-M-194-001, MOST 104-2811-M-194-004, MOST 104-2914-I-007-A1 and MOST 104-2811-M-194-016 is acknowledged. C. H. Chen acknowledges the support of postdoctoral research fellowship from Ministry of Science and Technology, Taiwan, R.O.C.
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Chen, CH., Wu, WT. & Wang, JN. All-fiber microfluidic multimode Mach–Zehnder interferometers as high sensitivity refractive index sensors. Microsyst Technol 23, 429–440 (2017). https://doi.org/10.1007/s00542-016-2928-x
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DOI: https://doi.org/10.1007/s00542-016-2928-x