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Spectral characteristics of polymer micro-fiber MZI near 1550 nm
Author's Accepted Manuscript
Spectral characteristics of polymer microfiber MZI near 1550 nm Fangju Li, Jing Zhang
www.elsevier.com/locate/physe
PII: DOI: Reference:
S1386-9477(14)00189-1 http://dx.doi.org/10.1016/j.physe.2014.05.018 PHYSE11614
To appear in:
Physica E
Received date: 6 April 2014 Revised date: 8 May 2014 Accepted date: 16 May 2014 Cite this article as: Fangju Li, Jing Zhang, Spectral characteristics of polymer micro-fiber MZI near 1550 nm, Physica E, http://dx.doi.org/10.1016/j. physe.2014.05.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Spectral characteristics of polymer micro-fiber MZI near 1550nm Fangju Li1, Jing Zhang2 1
School of Physics and Electrical Engineering, Weinan Normal University, Weinan, Shanxi, 714000, P. R. China 2 School of Physics and Materials Engineering, Dalian Nationalities University, Dalian, Liaoning, 116600, P. R. China Address: School of Physics and Electrical Engineering, Weinan Normal University, Chaoyang Street Western Part, Weinan, Shanxi, 714000, P. R. China Telephone number: +86-913-2133982 Fax number: +86-913-2133982 Email address: [email protected]
1
Abstract: The authors have produced the polymer micro-fiber with a highly optical conductive efficiency of 83% and 89% for the pump light of 532nm and 1550nm, respectively. The authors constructed a Mach-Zehnder Interferometer (MZI) by micro-manipulation method and measured the different interference spectra by micro-adjusting the path difference of the dual interference arms of MZI under a microscope. Due to the path difference, the coherent length of the corresponding spectrum continuously and slightly decreases from 20μm, 13.5μm, 10.6μm to 8μm. The relationships between this particular MZI structure and the surrounding temperature, as well as the refractive index changes can be determined via the evanescent field and the thermally induced expansion or contraction effect, respectively, which will be reflected in the interference spectrum. Keywords: Polymer, Micron Fiber, Mach-Zehnder Interferometer
2
INTRODUCTION Since the phase difference between two interference arms are very sensitive to the changes of external environment, Mach-Zehnder Interferometer (MZI) is widely used in temperature sensor, pressure sensor, optical communications and other fields [1-4]. In particular, with the development of micro and nano-fiber technology in recent years, photonic crystal fiber [5, 6], micro and nano-silica fiber [7], and metal wires [8] are introduced in MZI and studied widely. In these special MZI, the very high corresponding sensitivity and accuracy had been proved, since the evanescent field surrounding these micro and nano-devices is sensitive to the changes of external environment [9, 10]. In this paper, we manufactured a polymer micro-fiber (PMF) using methylmethacrylate (MMA), and prepared a special MZI by micro-manipulating two PMF to be as coupler arms. Such polymeric materials has the transparency of up to 90% in the visible and infrared light, the low melting point of 220 °C, which can also be easily integrated into other fiber optical systems. One can produce micro and nano-fiber from this polymer easily, and achieve the uniform distribution of laser dyes [11] and metal nano-particles doping polymer materials [12, 13] by organic solvent dissolving and ultrasonic oscillations method. POLYMER MICRO-FIBER MZI PREPARED METHODS Polymethylmethacrylate (PMMA) micro-fiber used in this paper is directly drawn from the melt block PMMA. First, we doped, mixed and dissolved the 0.005wt% azobisisobutyronitrile (AIBN) in MMA solution [14]. The laser dye or dispersing medium particle can be added if required at this moment. Pre-polymerization for two hours is needed at 75 °C. Reducing the temperature to 60 °C and polymerizing for two hours until the viscous mixture is got. After drying for 6 hours at 110 °C, we obtained the block PMMA. By placing the block PMMA on the heating plate, we got the PMF through heating method. The diameter of the PMF can be controlled by changing the drawing speed. The two prepared PMFs were disposed on an MgF2 substrate (with refractive index of 1.37 to reduce the optical loss), and produced the MZI structure by micro-manipulation under the microscope. The inset of Fig. 1 shows the image of the PMF-MZI, the corresponding diameter of PMF is about 2μm. The PMF with too small diameter is difficult to define and guide light effectively due to the low relative refractive index of 0.1 between PMF (1.47) and MgF2 substrate (1.37). In the experiment, the length of the coupling region for interferometer can be changed by micro-manipulating PMF. A fiber taper is fixed by a 3D fiber adjustment and used here to micro-manipulate the length of the bend arm of PMF-MZI. Once the needed length is obtained, the fiber taper will be moved away from the interferometer. Furthermore, two slim single-mode fibers were used here to introduce light into PMF-MZI, collect and measure the transmission light in a spectrum analyzer, respectively. The two single-mode fibers were fixed by two 3D fiber adjusting frames for changing the relative position between PMMA fiber and single mode fiber to ensure the high coupling efficiency. The left arrow indicates the direction of incident light. EXPERIMENTAL RESULTS AND ANALYSIS We studied the light transmission efficiency of PMF by launching the laser of 532nm and 1550nm from one end of PMF-MZI. The experimental data curves can be found in Fig. 2, in which the pump power and transmission power from another end of PMF are measured, respectively. The transmission efficiency of PMF for 532nm and 1550nm are about 83% and 89%, 3
respectively. The low transmission efficiency can be attributed to the rough surface of PMF. The inset shows the image of PMF under laser of 532nm, which is filtered by an attenuator with yellow color to protect CCD camera. The dark field micrograph indicates that the light was efficiently confined and launched in PMF. The light with the spectral width of 1525nm-1575nm is introduced into the PMF through a single mode fiber, whose position is adjusted by the three-dimensional (3D) adjustment frame to couple light into fiber with a high efficiency. The light is split into two beams at the front coupler, and re-combined at the other coupler of PMF-MZI. The interference beam is launched out through another single-mode optical fiber (which is fixed by a shelf in 3D adjustment frame), and measured by a spectrometer. The interference spectrum is shown in Fig. 3. The corresponding coherent length is about 10nm, which depends on the optical path difference of two interference arms, i.e., the path difference ΔL, which can be written as ΔL=λminλmax/(2ng |λmin-λmax|) and calculated through the adjacent minimum spectral position λmin, maximum spectral position λmax, as well as the group index of micro or nano-fiber ng. The group index can be expressed as [15] ng = n 2 ⋅
k
⎡1 − 2Δ (1 − η ) ⎤⎦ β⎣
(1)
Where, n is the refractive index of PMF; k=2π/λ is wave vector; Δ is varying factor; η is the fractional power inside the core of PMF; β is propagation constant, which can be got by solving the eigenvalue equation of a circular cross-section waveguide in cylindrical coordination [16, 17]. The forces between the two interference arms of PMF-MZI include the van der waals and electrostatic attractive forces [18], which are very weak and can be changed by micro-manipulating the path difference, results the change of the coherent length in interference spectra. In this paper, we measured the interference spectra for different path difference of MZI, which are shown in Fig. 4(a-d). The corresponding coherent lengths of the four interference spectra are 20μm, 13.5μm, 10μm, 6.8μm, respectively. In the actual measurement process, one can use the two PMFs as a fixed MZI structure, in which the path difference of interference arms will undergo thermally induced expansion and contraction according to the rise and fall of ambient temperature. The linear thermal expansion coefficient of PMMA is α=60ppm/ºC (α=ΔL/(LڄΔT)) [19]. That is, the path difference (for 10μm) will change for about 0.6nm/ºC. Meanwhile, the evanescent field around the circumference of PMF-MZI will be sensitive to the refractive index changes around the instrument. The variation will be reflected in the interference spectrum. Therefore, PMF-MZI can be used for real-time monitoring the refractive index changes of gases and liquids, as well as the fluctuation of ambient temperature. CONCLUSIONS In summary, the authors have designed a special MZI with two polymer micro-fibers drawing from block polymethylmethacrylate. The coherent lengths of interference spectra have been continuously adjusted from 20μm to 6.8μm by micro-adjusting the path difference of two polymer micro-fiber from 5.3μm to 21μm. Because of its sensitive to the changes of external environment, such as refractive index and temperature, this novel MZI may play a role in the temperature and refractive index sensors, and other micro-photonic devices. ACKNOWLEDGEMENTS This work was supported in part by the Shanxi Province Civilian Integration Research Project (No. 4
13JMR15), and National Natural Science Foundation of China (No. 11304230)
Captions: Fig. 1 The experimental setup; Inset is the microscopic image of micro-fiber coupler; the scale bar is 10 μm. Fig. 2 Experimental values and the fitted curves of the light guiding efficiency of PMF-MZI at 532nm (square, dotted line) and 1550nm (dots, solid line), respectively; the inset is the microscopic image of PMF-MZI in the light of 532nm Fig. 3 The interference spectrum for the optical path difference 16.8μm of PMF-MZI, the corresponding coherent length is about 10nm. Fig. 4 The interference spectra for the optical path difference (a. 5.3μm, b. 9.6μm, c. 16.8μm, d. 21μm); The corresponding coherent lengths of the four interference spectra are 20μm, 13.5μm, 10μm, 6.8μm, respectively.
5
REFERENCES [1] P. Lu, L. Men, K. Sooley, Q. Chen, Tapered fiber Mach–Zehnder interferometer for simultaneous measurement of refractive index and temperature, Appl. Phys. Lett., 94(13) (2009) 131110. [2] G. A. Cárdenas-Sevilla, D. Monzón-Hernández, I. Torres-Gómez, A. Martínez-Ríos, Tapered Mach–Zehnder interferometer based on two mechanically induced long-period fiber gratings as refractive index sensor, Opt. Laser Technol., 44(5) (2012) 1516-1520. [3] Q. K. Karim, Z. Liu, H. Y. Tam, M. Fahad Zia, A strain sensor based on in-line fiber Mach–Zehnder interferometer in twin-core photonic crystal fiber, Opt. Commun., 309 (2013) 68-70. [4] C. Yu, Y. Zhang, X. Zhang, K. Wang, C. Yao, P. Yuan, Nested fiber ring resonator enhanced Mach–Zehnder interferometer for temperature sensing, Appl. Opt., 51(36) (2012) 8873-8876. [5] M. Deng, C. P. Tang, T. Zhu, Y. J. Rao, Highly sensitive bend sensor based on Mach–Zehnder interferometer using photonic crystal fiber, Opt. Commun., 284(12) (2011) 2849-2853. [6] M. Yang, D. N. Wang, Y. Wang, C. R. Liao, Fiber in-line Mach–Zehnder interferometer constructed by selective infiltration of two air holes in photonic crystal fiber, Opt. Lett., 36(5) (2011) 636-638. [7] J. Xia, A. M. Rossi, T. E. Murphy, Laser-written nanoporous silicon ridge waveguide for highly sensitive optical sensors, Opt, Lett,, 37(2) (2012) 256-258. [8] M. Morimoto, Proposal for a Plasmonic Mach–Zehnder Modulator Utilizing Quantum Interference Effect, J. Sel. Top. Quant., 19(6) (2013) 1-7. [9] J. Wo, G. Wang, Y. Cui, Q. Sun, R. Liang, P. P. Shum, D. Liu, Refractive index sensor using microfiber-based Mach–Zehnder interferometer. Opt. Lett., 37(1) (2012) 67-69. [10] J. M. Hsu, C. L. Lee, H. P. Chang, W. C. Shih, C. M. Li, Highly sensitive tapered fiber Mach–Zehnder Interferometer for liquid level sensing, Photon. Technol. Lett., 25(14) (2013) 1354-1357. [11] F. X. Gu, L. Zhang, X. F. Yin, L. M. Tong, Polymer single-nanowire optical sensors, Nano Lett., 8(9), (2008) 2757-2716. [12] H. C. Y. Yu, A. Argyros, G. Barton, M. A. van Eijkelenborg, C. Barbe, K. Finnie, L. Kong, F. Ladouceur, S. McNiven, Quantum dot and silica nanoparticle doped polymer optical fibers, Opt. Express 15(16), (2007) 9989-9994. [13] S. Maity, L. N. Downen, J. R. Bochinski, L. I. Clarke, Embedded metal nanoparticles as localized heat sources: An alternative processing approach for complex polymeric materials, Polymer, 52(7), (2011) 1674-1685. [14] H. Li, J. Li, L. Qiang, Y. Zhang, S. Hao, Single-mode lasing of nanowire self-coupled resonator, Nanoscale, 5(14) (2013) 6297-6302. [15] L. Tong, J. Lou, E. Mazur, Single-mode guiding properties of subwavelength-diameter silica and silicon wire waveguides, Opt. Express, 12(6) (2004) 1025-1035. [16] A. W. Snyder and J. D. Love, Optical Waveguide Theory (Chapman and Hall, New York, 1983). [17] J. Lou, L. Tong, Z. Ye, Modeling of silica nanowires for optical sensing, Opt. Express, 13(6) (2005) 2135-2140. [18] Y. Li, L. Tong, Mach-Zehnder interferometers assembled with optical microfibers or nanofibers[J]. Opt. Lett., 33(4) (2008) 303-305. [19] R. Bashir, M. Ferrari, S. T. Wereley, BioMEMS and biomedical nanotechnology: Volume IV: Biomolecular sensing, processing and analysis (Springer, New York, 2007). 6
Highlights: 1. We produced a polymer micro-fiber with highly optical conductive efficiency. 2. We constructed a MZI by micro-manipulation method. 3. The coherent period of spectra continuously and slightly decreases with path difference.
7
Figure 1
Figure 2
Figure 3
Figure 4
Graphical Abstract (for review)
Spectral characteristics of polymer micro-fiber MZI near 1550nm Fangju Li1, Jing Zhang2 1
School of Physics and Electrical Engineering, Weinan Normal University, Weinan, Shanxi, 714000, P. R. China 2 School of Physics and Materials Engineering, Dalian Nationalities University, Dalian, Liaoning, 116600, P. R. China The authors constructed MZI by micro-manipulating polymer PMMA fibers and measured the interference spectra for different path differences of the dual interference arms.
Spectral characteristics of polymer microfiber MZI near 1550 nm Fangju Li, Jing Zhang
www.elsevier.com/locate/physe
PII: DOI: Reference:
S1386-9477(14)00189-1 http://dx.doi.org/10.1016/j.physe.2014.05.018 PHYSE11614
To appear in:
Physica E
Received date: 6 April 2014 Revised date: 8 May 2014 Accepted date: 16 May 2014 Cite this article as: Fangju Li, Jing Zhang, Spectral characteristics of polymer micro-fiber MZI near 1550 nm, Physica E, http://dx.doi.org/10.1016/j. physe.2014.05.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Spectral characteristics of polymer micro-fiber MZI near 1550nm Fangju Li1, Jing Zhang2 1
School of Physics and Electrical Engineering, Weinan Normal University, Weinan, Shanxi, 714000, P. R. China 2 School of Physics and Materials Engineering, Dalian Nationalities University, Dalian, Liaoning, 116600, P. R. China Address: School of Physics and Electrical Engineering, Weinan Normal University, Chaoyang Street Western Part, Weinan, Shanxi, 714000, P. R. China Telephone number: +86-913-2133982 Fax number: +86-913-2133982 Email address: [email protected]
1
Abstract: The authors have produced the polymer micro-fiber with a highly optical conductive efficiency of 83% and 89% for the pump light of 532nm and 1550nm, respectively. The authors constructed a Mach-Zehnder Interferometer (MZI) by micro-manipulation method and measured the different interference spectra by micro-adjusting the path difference of the dual interference arms of MZI under a microscope. Due to the path difference, the coherent length of the corresponding spectrum continuously and slightly decreases from 20μm, 13.5μm, 10.6μm to 8μm. The relationships between this particular MZI structure and the surrounding temperature, as well as the refractive index changes can be determined via the evanescent field and the thermally induced expansion or contraction effect, respectively, which will be reflected in the interference spectrum. Keywords: Polymer, Micron Fiber, Mach-Zehnder Interferometer
2
INTRODUCTION Since the phase difference between two interference arms are very sensitive to the changes of external environment, Mach-Zehnder Interferometer (MZI) is widely used in temperature sensor, pressure sensor, optical communications and other fields [1-4]. In particular, with the development of micro and nano-fiber technology in recent years, photonic crystal fiber [5, 6], micro and nano-silica fiber [7], and metal wires [8] are introduced in MZI and studied widely. In these special MZI, the very high corresponding sensitivity and accuracy had been proved, since the evanescent field surrounding these micro and nano-devices is sensitive to the changes of external environment [9, 10]. In this paper, we manufactured a polymer micro-fiber (PMF) using methylmethacrylate (MMA), and prepared a special MZI by micro-manipulating two PMF to be as coupler arms. Such polymeric materials has the transparency of up to 90% in the visible and infrared light, the low melting point of 220 °C, which can also be easily integrated into other fiber optical systems. One can produce micro and nano-fiber from this polymer easily, and achieve the uniform distribution of laser dyes [11] and metal nano-particles doping polymer materials [12, 13] by organic solvent dissolving and ultrasonic oscillations method. POLYMER MICRO-FIBER MZI PREPARED METHODS Polymethylmethacrylate (PMMA) micro-fiber used in this paper is directly drawn from the melt block PMMA. First, we doped, mixed and dissolved the 0.005wt% azobisisobutyronitrile (AIBN) in MMA solution [14]. The laser dye or dispersing medium particle can be added if required at this moment. Pre-polymerization for two hours is needed at 75 °C. Reducing the temperature to 60 °C and polymerizing for two hours until the viscous mixture is got. After drying for 6 hours at 110 °C, we obtained the block PMMA. By placing the block PMMA on the heating plate, we got the PMF through heating method. The diameter of the PMF can be controlled by changing the drawing speed. The two prepared PMFs were disposed on an MgF2 substrate (with refractive index of 1.37 to reduce the optical loss), and produced the MZI structure by micro-manipulation under the microscope. The inset of Fig. 1 shows the image of the PMF-MZI, the corresponding diameter of PMF is about 2μm. The PMF with too small diameter is difficult to define and guide light effectively due to the low relative refractive index of 0.1 between PMF (1.47) and MgF2 substrate (1.37). In the experiment, the length of the coupling region for interferometer can be changed by micro-manipulating PMF. A fiber taper is fixed by a 3D fiber adjustment and used here to micro-manipulate the length of the bend arm of PMF-MZI. Once the needed length is obtained, the fiber taper will be moved away from the interferometer. Furthermore, two slim single-mode fibers were used here to introduce light into PMF-MZI, collect and measure the transmission light in a spectrum analyzer, respectively. The two single-mode fibers were fixed by two 3D fiber adjusting frames for changing the relative position between PMMA fiber and single mode fiber to ensure the high coupling efficiency. The left arrow indicates the direction of incident light. EXPERIMENTAL RESULTS AND ANALYSIS We studied the light transmission efficiency of PMF by launching the laser of 532nm and 1550nm from one end of PMF-MZI. The experimental data curves can be found in Fig. 2, in which the pump power and transmission power from another end of PMF are measured, respectively. The transmission efficiency of PMF for 532nm and 1550nm are about 83% and 89%, 3
respectively. The low transmission efficiency can be attributed to the rough surface of PMF. The inset shows the image of PMF under laser of 532nm, which is filtered by an attenuator with yellow color to protect CCD camera. The dark field micrograph indicates that the light was efficiently confined and launched in PMF. The light with the spectral width of 1525nm-1575nm is introduced into the PMF through a single mode fiber, whose position is adjusted by the three-dimensional (3D) adjustment frame to couple light into fiber with a high efficiency. The light is split into two beams at the front coupler, and re-combined at the other coupler of PMF-MZI. The interference beam is launched out through another single-mode optical fiber (which is fixed by a shelf in 3D adjustment frame), and measured by a spectrometer. The interference spectrum is shown in Fig. 3. The corresponding coherent length is about 10nm, which depends on the optical path difference of two interference arms, i.e., the path difference ΔL, which can be written as ΔL=λminλmax/(2ng |λmin-λmax|) and calculated through the adjacent minimum spectral position λmin, maximum spectral position λmax, as well as the group index of micro or nano-fiber ng. The group index can be expressed as [15] ng = n 2 ⋅
k
⎡1 − 2Δ (1 − η ) ⎤⎦ β⎣
(1)
Where, n is the refractive index of PMF; k=2π/λ is wave vector; Δ is varying factor; η is the fractional power inside the core of PMF; β is propagation constant, which can be got by solving the eigenvalue equation of a circular cross-section waveguide in cylindrical coordination [16, 17]. The forces between the two interference arms of PMF-MZI include the van der waals and electrostatic attractive forces [18], which are very weak and can be changed by micro-manipulating the path difference, results the change of the coherent length in interference spectra. In this paper, we measured the interference spectra for different path difference of MZI, which are shown in Fig. 4(a-d). The corresponding coherent lengths of the four interference spectra are 20μm, 13.5μm, 10μm, 6.8μm, respectively. In the actual measurement process, one can use the two PMFs as a fixed MZI structure, in which the path difference of interference arms will undergo thermally induced expansion and contraction according to the rise and fall of ambient temperature. The linear thermal expansion coefficient of PMMA is α=60ppm/ºC (α=ΔL/(LڄΔT)) [19]. That is, the path difference (for 10μm) will change for about 0.6nm/ºC. Meanwhile, the evanescent field around the circumference of PMF-MZI will be sensitive to the refractive index changes around the instrument. The variation will be reflected in the interference spectrum. Therefore, PMF-MZI can be used for real-time monitoring the refractive index changes of gases and liquids, as well as the fluctuation of ambient temperature. CONCLUSIONS In summary, the authors have designed a special MZI with two polymer micro-fibers drawing from block polymethylmethacrylate. The coherent lengths of interference spectra have been continuously adjusted from 20μm to 6.8μm by micro-adjusting the path difference of two polymer micro-fiber from 5.3μm to 21μm. Because of its sensitive to the changes of external environment, such as refractive index and temperature, this novel MZI may play a role in the temperature and refractive index sensors, and other micro-photonic devices. ACKNOWLEDGEMENTS This work was supported in part by the Shanxi Province Civilian Integration Research Project (No. 4
13JMR15), and National Natural Science Foundation of China (No. 11304230)
Captions: Fig. 1 The experimental setup; Inset is the microscopic image of micro-fiber coupler; the scale bar is 10 μm. Fig. 2 Experimental values and the fitted curves of the light guiding efficiency of PMF-MZI at 532nm (square, dotted line) and 1550nm (dots, solid line), respectively; the inset is the microscopic image of PMF-MZI in the light of 532nm Fig. 3 The interference spectrum for the optical path difference 16.8μm of PMF-MZI, the corresponding coherent length is about 10nm. Fig. 4 The interference spectra for the optical path difference (a. 5.3μm, b. 9.6μm, c. 16.8μm, d. 21μm); The corresponding coherent lengths of the four interference spectra are 20μm, 13.5μm, 10μm, 6.8μm, respectively.
5
REFERENCES [1] P. Lu, L. Men, K. Sooley, Q. Chen, Tapered fiber Mach–Zehnder interferometer for simultaneous measurement of refractive index and temperature, Appl. Phys. Lett., 94(13) (2009) 131110. [2] G. A. Cárdenas-Sevilla, D. Monzón-Hernández, I. Torres-Gómez, A. Martínez-Ríos, Tapered Mach–Zehnder interferometer based on two mechanically induced long-period fiber gratings as refractive index sensor, Opt. Laser Technol., 44(5) (2012) 1516-1520. [3] Q. K. Karim, Z. Liu, H. Y. Tam, M. Fahad Zia, A strain sensor based on in-line fiber Mach–Zehnder interferometer in twin-core photonic crystal fiber, Opt. Commun., 309 (2013) 68-70. [4] C. Yu, Y. Zhang, X. Zhang, K. Wang, C. Yao, P. Yuan, Nested fiber ring resonator enhanced Mach–Zehnder interferometer for temperature sensing, Appl. Opt., 51(36) (2012) 8873-8876. [5] M. Deng, C. P. Tang, T. Zhu, Y. J. Rao, Highly sensitive bend sensor based on Mach–Zehnder interferometer using photonic crystal fiber, Opt. Commun., 284(12) (2011) 2849-2853. [6] M. Yang, D. N. Wang, Y. Wang, C. R. Liao, Fiber in-line Mach–Zehnder interferometer constructed by selective infiltration of two air holes in photonic crystal fiber, Opt. Lett., 36(5) (2011) 636-638. [7] J. Xia, A. M. Rossi, T. E. Murphy, Laser-written nanoporous silicon ridge waveguide for highly sensitive optical sensors, Opt, Lett,, 37(2) (2012) 256-258. [8] M. Morimoto, Proposal for a Plasmonic Mach–Zehnder Modulator Utilizing Quantum Interference Effect, J. Sel. Top. Quant., 19(6) (2013) 1-7. [9] J. Wo, G. Wang, Y. Cui, Q. Sun, R. Liang, P. P. Shum, D. Liu, Refractive index sensor using microfiber-based Mach–Zehnder interferometer. Opt. Lett., 37(1) (2012) 67-69. [10] J. M. Hsu, C. L. Lee, H. P. Chang, W. C. Shih, C. M. Li, Highly sensitive tapered fiber Mach–Zehnder Interferometer for liquid level sensing, Photon. Technol. Lett., 25(14) (2013) 1354-1357. [11] F. X. Gu, L. Zhang, X. F. Yin, L. M. Tong, Polymer single-nanowire optical sensors, Nano Lett., 8(9), (2008) 2757-2716. [12] H. C. Y. Yu, A. Argyros, G. Barton, M. A. van Eijkelenborg, C. Barbe, K. Finnie, L. Kong, F. Ladouceur, S. McNiven, Quantum dot and silica nanoparticle doped polymer optical fibers, Opt. Express 15(16), (2007) 9989-9994. [13] S. Maity, L. N. Downen, J. R. Bochinski, L. I. Clarke, Embedded metal nanoparticles as localized heat sources: An alternative processing approach for complex polymeric materials, Polymer, 52(7), (2011) 1674-1685. [14] H. Li, J. Li, L. Qiang, Y. Zhang, S. Hao, Single-mode lasing of nanowire self-coupled resonator, Nanoscale, 5(14) (2013) 6297-6302. [15] L. Tong, J. Lou, E. Mazur, Single-mode guiding properties of subwavelength-diameter silica and silicon wire waveguides, Opt. Express, 12(6) (2004) 1025-1035. [16] A. W. Snyder and J. D. Love, Optical Waveguide Theory (Chapman and Hall, New York, 1983). [17] J. Lou, L. Tong, Z. Ye, Modeling of silica nanowires for optical sensing, Opt. Express, 13(6) (2005) 2135-2140. [18] Y. Li, L. Tong, Mach-Zehnder interferometers assembled with optical microfibers or nanofibers[J]. Opt. Lett., 33(4) (2008) 303-305. [19] R. Bashir, M. Ferrari, S. T. Wereley, BioMEMS and biomedical nanotechnology: Volume IV: Biomolecular sensing, processing and analysis (Springer, New York, 2007). 6
Highlights: 1. We produced a polymer micro-fiber with highly optical conductive efficiency. 2. We constructed a MZI by micro-manipulation method. 3. The coherent period of spectra continuously and slightly decreases with path difference.
7
Figure 1
Figure 2
Figure 3
Figure 4
Graphical Abstract (for review)
Spectral characteristics of polymer micro-fiber MZI near 1550nm Fangju Li1, Jing Zhang2 1
School of Physics and Electrical Engineering, Weinan Normal University, Weinan, Shanxi, 714000, P. R. China 2 School of Physics and Materials Engineering, Dalian Nationalities University, Dalian, Liaoning, 116600, P. R. China The authors constructed MZI by micro-manipulating polymer PMMA fibers and measured the interference spectra for different path differences of the dual interference arms.