OSA's Digital Library

Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 21, Iss. 17 — Aug. 26, 2013
  • pp: 19808–19815
« Show journal navigation

Self-supporting polymer pipes for low loss single-mode THz transmission

Mingfei Xiao, Jing Liu, Wei Zhang, Jingling Shen, and Yidong Huang  »View Author Affiliations


Optics Express, Vol. 21, Issue 17, pp. 19808-19815 (2013)
http://dx.doi.org/10.1364/OE.21.019808


View Full Text Article

Acrobat PDF (1217 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

In this paper, a self-supporting polymer pipe is proposed and investigated for THz wave transmission. Utilizing fiber drawing technique for polymer fiber, self-supporting pipes with wall thickness of several tens micrometers can be fabricated using polymethylmethacrylate (PMMA). The guiding mechanism and transmission characteristics of the self-supporting pipes are investigated theoretically, showing that it can support single-mode transmission at THz band. The self-supporting pipe samples with different structure parameters are fabricated and measured experimentally, showing that it can support single HE11 mode transmission. Theoretical analysis and experimental results show that this self-supporting polymer pipe is a promising candidate for low loss THz fibers.

© 2013 OSA

1. Introduction

In this paper, a self-supporting polymer pipe is proposed and investigated for low loss THz transmission. Theoretical analysis indicates that low transmission loss and large transmission bandwidth can be achieved in this structure. Furthermore, by analyzing the characteristics of the fundamental mode and higher order modes in the self-supporting pipe, we find this structure supports single-mode transmission at THz band. Then the self-supporting polymer pipes are fabricated and measured utilizing a CO2 laser-pumped THz laser operating at 3.1THz. The mechanism of low loss single mode transmission in the self-supporting pipe is demonstrated experimentally.

2. Self-supporting polymer pipe fabricated by PMMA

3. Theoretical analysis

Two kinds of models are proposed to analyze the transmission characteristics of self-supporting PMMA pipe theoretically. The first one is shown in Fig. 1(b), which has a hexagonal inner pipe supported by six thin walls. The distance between the apex and the center of the hexagonal inner pipe is denoted by rh, the thickness of the hexagonal inner pipe is denoted by th. The radius and thickness of the outer pipe are denoted by Rh and Th, respectively. The transmission characteristics of this waveguide model can be calculated by the finite element method (FEM). Considering that the light confinement in this structure is mainly due to the reflection of the inner pipe, the model shown in Fig. 1(b) can be farther simplified to Fig. 1(c), in which the inner pipe is simplified to a round thin wall pipe, while the supporting walls are neglected. Similar simplification has been applied in the analysis on Kagome fiber [21

21. G. J. Pearce, G. S. Wiederhecker, C. G. Poulton, S. Burger, and P. St J Russell, “Models for guidance in kagome-structured hollow-core photonic crystal fibres,” Opt. Express 15(20), 12680–12685 (2007). [CrossRef] [PubMed]

, 22

22. D. S. Wu, A. Argyros, and S. G. Leon-Saval, “Reducing the size of hollow terahertz waveguides,” J. Lightwave Technol. 29(1), 97–103 (2011). [CrossRef]

]. In this model, the radius and thickness of the inner pipe are denoted by r and t, while, the radius and thickness of the outer pipe are denoted by R and T. The simplified model shown in Fig. 1(c) can be calculated by the transfer matrix method (TMM).

Firstly, the attenuation spectrum of the HE11 mode from 2THz to 5THz in this structure are calculated and shown in Fig. 2
Fig. 2 Calculated attenuation spectra of HE11 mode in self-supporting pipes. The green down-triangles are calculated by model of Fig. 1(b), the black squares are calculated by model of Fig. 1(c), the blue up-triangles and red circles are calculated attenuation spectra of HE11 mode in only the inner pipe and only the outer pipe, respectively
. The green triangles and black squares are the calculation results of the models shown in Fig. 1(b) and 1(c), respectively. In the calculation, typical structure parameters are used, which are shown in Table 1

Table 1. Structure parameters used in calculation

table-icon
View This Table
.

The index of the polymer material is assumed to 1.53 + 0.003i [23

23. P. D. Cunningham, N. N. Valdes, F. A. Vallejo, L. M. Hayden, B. Polishak, X. H. Zhou, J. D. Luo, A. K.-Y. Jen, J. C. Williams, and R. J. Twieg, “Broadband terahertz characterization of the refractive index and absorption of some important polymeric and organic electro-optic materials,” Appl. Phys. Lett. 109(4), 043505 (2011).

]. It can be seen that the attenuation spectra calculated by the two models agree well. Although the simplified model may underestimate the attenuation at low frequency region, the low loss transmission bands and high loss frequency region between them can be indicated correctly by it. In the following analysis, we use the simplified model [shown in Fig. 1(c)] to investigate the guiding mechanism and transmission characteristics of the self-supporting pipe.

To demonstrate the guiding mechanism of the self-supporting pipe, the attenuation spectra of the inner pipe and the outer pipe in the simplified model are calculated separately, and shown in Fig. 2 as the blue up-triangles and red solid circles, respectively. It can be seen that due to its thin thickness, the transmission band of inner pipe is very broad, almost all the frequency region of the calculation is in a low loss anti-resonance transmission band, which shows that due to the extreme thin wall thickness, the inner pipe alone can act as an effective antiresonant THz waveguide. While, the transmission band of the outer pipe is far narrow than that of the inner pipe. At the frequencies that the outer pipe is in the anti-resonance band, the attenuation of the self-supporting pipe is lower than that of the inner pipe, since the anti-resonance of the outer pipe provides additional light confinement to the field leaking to the area between the inner and the outer pipes. On the other hand, at the frequencies that the outer pipe has high loss due to the resonance condition of its wall, the attenuation of the self-supporting pipe is close to that of the inner pipe, showing that the field leaking from the inner pipe is lost due to the leakage and the material absorption of the outer pipe. At the frequencies that the inner pipe has high loss, it can be expected that the field cannot confined in the inner pipe effectively, much field leaks out of the inner pipe and the light confinement is mainly provide by the outer pipe. It worth to note that the calculated attenuation by the simplified model with inner pipe is always lower than the case of outer pipe only, showing that the introduction of the inner pipe do not introduce additional loss, but improve the transmission performance by combining the guiding effects of inner pipe and outer pipe together.

Figure 3
Fig. 3 The impacts of structure parameter variations on the attenuation spectra of the self-supporting pipe calculated by the simplified model shown in Fig. 1(c).
shows the variations of the attenuation spectra of the HE11 mode in the self-supporting pipe when the structure parameters changes. According to the analysis on Fig. 2, the calculation results can be understood clearly by the effects of the inner pipe and the outer pipe. Figure 3(a) and 3(b) show the results when the radius r and wall thickness t of the inner pipe changes, respectively. Other parameters are unchanged as Table 1 in the calculation. It can be seen that the increasing r doesn’t change the low loss transmission band, while it is extremely helpful in reducing the attenuation coefficient. On the other hand, the transmission band of the self-supporting pipe is sensitive to the variation of t. These results are similar to the case that only the inner pipe is considered. The spectrum variations under different radius R and wall thickness T of the outer pipe are calculated in a relatively narrower band and shown in Fig. 3(c) and 3(d) respectively, in which other structural parameters are also unchanged as Table 1. It can be seen that the resonance condition in the outer pipe wall leads to the ripples in the spectrum, which are determined by T. On the other hand, the attenuation spectrum is almost unchanged under different R. According to Fig. 3, it can be concluded that to realize a THz fiber at a certain frequency, t is the main design parameters to optimize the low loss transmission band. Larger r is preferred to reduce the transmission loss, while R can be designed to a relatively small value, which is helpful to improve the flexibility of the self-supporting pipe as a THz fiber.

4. Experiment results

The experimental setup to measure the transmission characteristics of the self-supporting PMMA pipes is shown in Fig. 6
Fig. 6 The experimental setup for THz transmission of the self-supporting PMMA pipes.
. A CO2 laser-pumped THz laser (SIFIR-50 FPL Far-Infrared Laser System) provides a THz wave output at 3.1 THz. A Teflon lens with a focal length of 150 mm is used to focus the wave to a variable diaphragm. Its diameter is the same as that of the inner pipe of the sample. The self-supporting pipe sample places right after the diaphragm. Both ends of the sample, tinfoil is used to cover the area between the inner pipe and outer pipe to eliminate the impacts of the modes guiding in this region, with a hole in the center for light coupling to and out of the modes guiding in the inner pipe. A THz camera (Pyroelectric Array Camera Pyrocamtm Iii Series) is used to detect the field pattern at the output end of the sample.

Three self-supporting pipe samples are fabricated with different structural parameters, rh of which is about 0.5mm, 1mm, 1.5mm respectively, corresponding to the three different conditions in Fig. 4. Figure 7
Fig. 7 Typical field patterns at the output end of the pipe samples with the lengths of 0.15m and rh of 0.5mm (a), 1mm (b), 1.5mm (c).
is the measured output field patterns of different samples under various coupling conditions, which is adjusted by changing the location of the sample input end and the angle between the sample and the output direction of the laser. The sample 1 has the smallest inner pipe size among the three samples. The measured output field is very weak under all the possible coupling conditions, which is shown in Fig. 7(a). It is due to that the fields of HE11 mode and other higher order modes extend to the area between the inner pipe and the outer pipe, which is blocked by the tinfoil at the output end of the pipe. The sample 3 has the largest pipe size among the three samples. Figure 7(c) shows the output field patterns of the sample 3 under different coupling conditions. It can be seen that the field pattern varies with the coupling condition, showing the characteristics of multi-mode transmission clearly. The measured results for the sample 2 are shown in Fig. 7(b). It can be seen that the output field pattern is a single round spot under different coupling condition, showing that in this sample single HE11 mode transmission is realized. Hence, these experiment results demonstrate the mechanism of single mode transmission in the self-supporting pipe analyzed in Fig. 4.

Calculated by the measurement results of the THz wave intensity behind the diaphragm at the input end and the output intensity at the output end of the pipe, the insertion loss of the sample 2 (15cm in length) is 5.34 dB including the coupling loss at the input end.

5. Summary

In this paper, a self-supporting polymer pipe is proposed for THz wave transmission. Utilizing fiber drawing technique for polymer fiber, self-supporting pipes with wall thickness of several tens micrometers can be fabricated using PMMA. Utilizing the simplified model for the pipe, the effects of the inner pipe and outer pipe are analyzed. Theoretical analysis also shows that the pipe can support single HE11 mode transmission if the radius of the inner pipe is designed properly. In experiments, the self-supporting pipe samples with different structure parameters are fabricated and measured, demonstrating the single mode transmission in the pipe sample. The insertion loss of the single HE11 mode transmission of a 15cm sample is 5.34 dB. Theoretical analysis and experimental measurement show that the proposed self-supporting polymer pipe is a promising candidate for high-quality THz fibers.

Acknowledgment

This work is supported in part by 973 Programs of China under Contract No. 2010CB327600, Nature Science Foundation of Beijing under Grant No. 4102016 and Basic Research Foundation of Tsinghua National Laboratory for Information Science and Technology (TNList).

References and links

1.

M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics 1(2), 97–105 (2007). [CrossRef]

2.

P. H. Siegel, “Terahertz technology,” IEEE Trans. Microw. Theory Tech. 50(3), 910–928 (2002). [CrossRef]

3.

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications—explosives, weapons and drugs,” Semicond. Sci. Technol. 20(7), S266–S280 (2005). [CrossRef]

4.

W. R. Tribe, D. A. Newnham, P. F. Taday, and M. C. Kemp, “Hidden object detection: security applications of terahertz technology,” Proc. SPIE 5354, 168–176 (2004). [CrossRef]

5.

B. B. Hu and M. C. Nuss, “Imaging with terahertz waves,” Opt. Lett. 20(16), 1716–1718 (1995). [CrossRef] [PubMed]

6.

G. Gallot, S. P. Jamison, R. W. McGowan, and D. Grischkowsky, “Terahertz waveguides,” J. Opt. Soc. Am. B 17(5), 851–863 (2000). [CrossRef]

7.

B. Bowden, J. A. Harrington, and O. Mitrofanov, “Low-loss modes in hollow metallic terahertz waveguides with dielectric coatings,” Appl. Phys. Lett. 93(18), 181104 (2008). [CrossRef]

8.

A. Dupuis, K. Stoeffler, B. Ung, C. Dubois, and M. Skorobogatiy, “Transmission measurements of hollow-core THz Bragg fibers,” J. Opt. Soc. Am. B 28(4), 896–907 (2011). [CrossRef]

9.

T. Hidaka, H. Minamide, H. Ito, J. Nishizawa, K. Tamura, and S. Ichikawa, “Ferroelectric PVDF cladding terahertz waveguide,” J. Lightwave Technol. 23(8), 2469–2473 (2005). [CrossRef]

10.

K. Nielsen, H. K. Rasmussen, P. U. Jepsen, and O. Bang, “Porous-core honeycomb bandgap THz fiber,” Opt. Lett. 36(5), 666–668 (2011). [CrossRef] [PubMed]

11.

H. Bao, K. Nielsen, H. K. Rasmussen, P. U. Jepsen, and O. Bang, “Fabrication and characterization of porous-core honeycomb bandgap THz fibers,” Opt. Express 20(28), 29507–29517 (2012). [CrossRef] [PubMed]

12.

A. Dupuis, J. F. Allard, D. Morris, K. Stoeffler, C. Dubois, and M. Skorobogatiy, “Fabrication and THz loss measurements of porous subwavelength fibers using a directional coupler method,” Opt. Express 17(10), 8012–8028 (2009). [CrossRef] [PubMed]

13.

A. Dupuis, A. Mazhorova, F. Désévédavy, M. Rozé, and M. Skorobogatiy, “Spectral characterization of porous dielectric subwavelength THz fibers fabricated using a microstructured molding technique,” Opt. Express 18(13), 13813–13828 (2010). [CrossRef] [PubMed]

14.

M. Rozé, B. Ung, A. Mazhorova, M. Walther, and M. Skorobogatiy, “Suspended core subwavelength fibers: towards practical designs for low-loss terahertz guidance,” Opt. Express 19(10), 9127–9138 (2011). [CrossRef] [PubMed]

15.

C.-H. Lai, B. You, J.-Y. Lu, T.-A. Liu, J.-L. Peng, C.-K. Sun, and H.-C. Chang, “Modal characteristics of antiresonant reflecting pipe waveguides for terahertz waveguiding,” Opt. Express 18(1), 309–322 (2010). [CrossRef] [PubMed]

16.

A. Mazhorova, A. Markov, B. Ung, M. Roze, S. Gorgutsa, and M. Skorobogatiy, “Thin chalcogenide capillaries as efficient waveguides from mid-infrared to terahertz,” J. Opt. Soc. Am. B 29(8), 2116–2123 (2012). [CrossRef]

17.

B. Ung, A. Mazhorova, A. Dupuis, M. Rozé, and M. Skorobogatiy, “Polymer microstructured optical fibers for terahertz wave guiding,” Opt. Express 19(26), B848–B861 (2011). [CrossRef] [PubMed]

18.

C.-H. Lai, Y.-C. Hsueh, H.-W. Chen, Y.-J. Huang, H.-C. Chang, and C.-K. Sun, “Low-index terahertz pipe waveguides,” Opt. Lett. 34(21), 3457–3459 (2009). [CrossRef] [PubMed]

19.

E. Nguema, D. Férachou, G. Humbert, J. L. Auguste, and J. M. Blondy, “Broadband terahertz transmission within the air channel of thin-wall pipe,” Opt. Lett. 36(10), 1782–1784 (2011). [CrossRef] [PubMed]

20.

M. F. Xiao, J. Liu, W. Zhang, J. L. Shen, and Y. D. Huang, “THz wave transmission in thin-wall PMMA pipes fabricated by fiber drawing technique,” Opt. Commun. 298, 101–105 (2013). [CrossRef]

21.

G. J. Pearce, G. S. Wiederhecker, C. G. Poulton, S. Burger, and P. St J Russell, “Models for guidance in kagome-structured hollow-core photonic crystal fibres,” Opt. Express 15(20), 12680–12685 (2007). [CrossRef] [PubMed]

22.

D. S. Wu, A. Argyros, and S. G. Leon-Saval, “Reducing the size of hollow terahertz waveguides,” J. Lightwave Technol. 29(1), 97–103 (2011). [CrossRef]

23.

P. D. Cunningham, N. N. Valdes, F. A. Vallejo, L. M. Hayden, B. Polishak, X. H. Zhou, J. D. Luo, A. K.-Y. Jen, J. C. Williams, and R. J. Twieg, “Broadband terahertz characterization of the refractive index and absorption of some important polymeric and organic electro-optic materials,” Appl. Phys. Lett. 109(4), 043505 (2011).

OCIS Codes
(060.2280) Fiber optics and optical communications : Fiber design and fabrication
(060.4005) Fiber optics and optical communications : Microstructured fibers

ToC Category:
Fiber Optics and Optical Communications

History
Original Manuscript: June 18, 2013
Revised Manuscript: August 6, 2013
Manuscript Accepted: August 6, 2013
Published: August 15, 2013

Citation
Mingfei Xiao, Jing Liu, Wei Zhang, Jingling Shen, and Yidong Huang, "Self-supporting polymer pipes for low loss single-mode THz transmission," Opt. Express 21, 19808-19815 (2013)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-21-17-19808


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics1(2), 97–105 (2007). [CrossRef]
  2. P. H. Siegel, “Terahertz technology,” IEEE Trans. Microw. Theory Tech.50(3), 910–928 (2002). [CrossRef]
  3. J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications—explosives, weapons and drugs,” Semicond. Sci. Technol.20(7), S266–S280 (2005). [CrossRef]
  4. W. R. Tribe, D. A. Newnham, P. F. Taday, and M. C. Kemp, “Hidden object detection: security applications of terahertz technology,” Proc. SPIE5354, 168–176 (2004). [CrossRef]
  5. B. B. Hu and M. C. Nuss, “Imaging with terahertz waves,” Opt. Lett.20(16), 1716–1718 (1995). [CrossRef] [PubMed]
  6. G. Gallot, S. P. Jamison, R. W. McGowan, and D. Grischkowsky, “Terahertz waveguides,” J. Opt. Soc. Am. B17(5), 851–863 (2000). [CrossRef]
  7. B. Bowden, J. A. Harrington, and O. Mitrofanov, “Low-loss modes in hollow metallic terahertz waveguides with dielectric coatings,” Appl. Phys. Lett.93(18), 181104 (2008). [CrossRef]
  8. A. Dupuis, K. Stoeffler, B. Ung, C. Dubois, and M. Skorobogatiy, “Transmission measurements of hollow-core THz Bragg fibers,” J. Opt. Soc. Am. B28(4), 896–907 (2011). [CrossRef]
  9. T. Hidaka, H. Minamide, H. Ito, J. Nishizawa, K. Tamura, and S. Ichikawa, “Ferroelectric PVDF cladding terahertz waveguide,” J. Lightwave Technol.23(8), 2469–2473 (2005). [CrossRef]
  10. K. Nielsen, H. K. Rasmussen, P. U. Jepsen, and O. Bang, “Porous-core honeycomb bandgap THz fiber,” Opt. Lett.36(5), 666–668 (2011). [CrossRef] [PubMed]
  11. H. Bao, K. Nielsen, H. K. Rasmussen, P. U. Jepsen, and O. Bang, “Fabrication and characterization of porous-core honeycomb bandgap THz fibers,” Opt. Express20(28), 29507–29517 (2012). [CrossRef] [PubMed]
  12. A. Dupuis, J. F. Allard, D. Morris, K. Stoeffler, C. Dubois, and M. Skorobogatiy, “Fabrication and THz loss measurements of porous subwavelength fibers using a directional coupler method,” Opt. Express17(10), 8012–8028 (2009). [CrossRef] [PubMed]
  13. A. Dupuis, A. Mazhorova, F. Désévédavy, M. Rozé, and M. Skorobogatiy, “Spectral characterization of porous dielectric subwavelength THz fibers fabricated using a microstructured molding technique,” Opt. Express18(13), 13813–13828 (2010). [CrossRef] [PubMed]
  14. M. Rozé, B. Ung, A. Mazhorova, M. Walther, and M. Skorobogatiy, “Suspended core subwavelength fibers: towards practical designs for low-loss terahertz guidance,” Opt. Express19(10), 9127–9138 (2011). [CrossRef] [PubMed]
  15. C.-H. Lai, B. You, J.-Y. Lu, T.-A. Liu, J.-L. Peng, C.-K. Sun, and H.-C. Chang, “Modal characteristics of antiresonant reflecting pipe waveguides for terahertz waveguiding,” Opt. Express18(1), 309–322 (2010). [CrossRef] [PubMed]
  16. A. Mazhorova, A. Markov, B. Ung, M. Roze, S. Gorgutsa, and M. Skorobogatiy, “Thin chalcogenide capillaries as efficient waveguides from mid-infrared to terahertz,” J. Opt. Soc. Am. B29(8), 2116–2123 (2012). [CrossRef]
  17. B. Ung, A. Mazhorova, A. Dupuis, M. Rozé, and M. Skorobogatiy, “Polymer microstructured optical fibers for terahertz wave guiding,” Opt. Express19(26), B848–B861 (2011). [CrossRef] [PubMed]
  18. C.-H. Lai, Y.-C. Hsueh, H.-W. Chen, Y.-J. Huang, H.-C. Chang, and C.-K. Sun, “Low-index terahertz pipe waveguides,” Opt. Lett.34(21), 3457–3459 (2009). [CrossRef] [PubMed]
  19. E. Nguema, D. Férachou, G. Humbert, J. L. Auguste, and J. M. Blondy, “Broadband terahertz transmission within the air channel of thin-wall pipe,” Opt. Lett.36(10), 1782–1784 (2011). [CrossRef] [PubMed]
  20. M. F. Xiao, J. Liu, W. Zhang, J. L. Shen, and Y. D. Huang, “THz wave transmission in thin-wall PMMA pipes fabricated by fiber drawing technique,” Opt. Commun.298, 101–105 (2013). [CrossRef]
  21. G. J. Pearce, G. S. Wiederhecker, C. G. Poulton, S. Burger, and P. St J Russell, “Models for guidance in kagome-structured hollow-core photonic crystal fibres,” Opt. Express15(20), 12680–12685 (2007). [CrossRef] [PubMed]
  22. D. S. Wu, A. Argyros, and S. G. Leon-Saval, “Reducing the size of hollow terahertz waveguides,” J. Lightwave Technol.29(1), 97–103 (2011). [CrossRef]
  23. P. D. Cunningham, N. N. Valdes, F. A. Vallejo, L. M. Hayden, B. Polishak, X. H. Zhou, J. D. Luo, A. K.-Y. Jen, J. C. Williams, and R. J. Twieg, “Broadband terahertz characterization of the refractive index and absorption of some important polymeric and organic electro-optic materials,” Appl. Phys. Lett.109(4), 043505 (2011).

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited