OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 27 — Dec. 17, 2012
  • pp: 28431–28436
« Show journal navigation

Miniaturized broadband highly birefringent device with stereo rod-microfiber-air structure

Jun-long Kou, Ye Chen, Fei Xu, and Yan-qing Lu  »View Author Affiliations


Optics Express, Vol. 20, Issue 27, pp. 28431-28436 (2012)
http://dx.doi.org/10.1364/OE.20.028431


View Full Text Article

Acrobat PDF (2333 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

A wrapping-on-a-rod technique is presented and demonstrated successfully to realize broadband microfiber-based highly birefringent (Hi-Bi) devices with 3D geometry. By wrapping a circular microfiber (MF) on a Teflon-coated rod (2 mm in diameter), a large and broadband birefringence can be obtained utilizing a rod-microfiber-air (RMA) structure. Wavelength scanning method is used to measure the birefringence of the device. Results show that group birefringence as high as 10−3 can be achieved over 400 nm wavelength range. This compact element presents great potential in sensing and communication applications, as well as lab-on-a-rod devices.

© 2012 OSA

1. Introduction

Maintaining the polarization state of transmission is of great importance in some systems where random mode coupling of the propagating signal can lead to serious deterioration in system reliability and performance. To overcome this problem, researchers have developed highly birefringent (Hi-Bi) fibers. Conventionally, the internal birefringence of Hi-Bi fibers can be produced by introducing stress applying parts around the fiber core (e.g., commercial PANDA [1

1. T. Hosaka, K. Okamoto, T. Miya, Y. Sasaki, and T. Edahiro, “Low-loss single polarization fibres with asymmetrical strain birefringence,” Electron. Lett. 17(15), 530–531 (1981). [CrossRef]

], Bow-Tie fibers [2

2. M. P. Varnham, D. N. Payne, R. D. Birch, and E. J. Tarbox, “Single-polarization operation of highly birefringent bow-tie optical fibres,” Electron. Lett. 19(7), 246–247 (1983). [CrossRef]

] and internal elliptical cladding fiber [3

3. V. Ramaswamy, R. H. Stolen, M. D. Divino, and W. Pleibel, “Birefringence in elliptically clad borosilicate single-mode fibers,” Appl. Opt. 18(24), 4080–4084 (1979). [CrossRef] [PubMed]

]) or by geometrical effect of the core (e.g., D-shaped fiber [4

4. A. Kumar, V. Gupta, and K. Thyagarajan, “Geometrical birefringence of polished and D-shape fibers,” Opt. Commun. 61(3), 195–198 (1987). [CrossRef]

] and elliptical core fiber [5

5. R. B. Dyott, J. R. Cozens, and D. G. Morris, “Preservation of polarisation in optical-fibre waveguides with elliptical cores,” Electron. Lett. 15(13), 380–382 (1979). [CrossRef]

]). All these optical fibers support two orthogonally polarized modes and the birefringence is on the order of 10−4 - 10−5. Recently, Hi-Bi photonic crystal fibers (PCFs) have also been fabricated [6

6. X. Chen, M. J. Li, N. Venkataraman, M. T. Gallagher, W. A. Wood, A. M. Crowley, J. P. Carberry, L. A. Zenteno, and K. W. Koch, “Highly birefringent hollow-core photonic bandgap fiber,” Opt. Express 12(16), 3888–3893 (2004). [CrossRef] [PubMed]

]. However, all these bulky 125-um-diameter fibers are not suitable for integrating in future micro/nano-photonics. Moreover, the fabrication cost for Hi-Bi PCFs remains a serious problem.

On the other hand, following the ever-growing development of micro/nano-photonics, microfibers (MFs) are of great interest for researchers because of their low loss, large evanescent fields, strong confinement, configurability, and robustness. They have found potential applications in a wide range of fields from telecommunications to sensors, and lasers [7

7. J. L. Kou, M. Ding, J. Feng, Y. Q. Lu, F. Xu, and G. Brambilla, “Microfiber-based Bragg gratings for sensing applications: a review,” Sensors (Basel) 12(7), 8861–8876 (2012). [CrossRef] [PubMed]

17

17. J. L. Kou, F. Xu, and Y. Q. Lu, “Highly birefringent slot-microfiber,” IEEE Photon. Technol. Lett. 23(15), 1034–1036 (2011). [CrossRef]

]. Among them, Hi-Bi MFs have been proposed or demonstrated exploiting different structures, such as flat fiber with rectangle cross section [12

12. Y. Jung, G. Brambilla, K. Oh, and D. J. Richardson, “Highly birefringent silica microfiber,” Opt. Lett. 35(3), 378–380 (2010). [CrossRef] [PubMed]

, 13

13. L. Sun, J. Li, Y. Tan, X. Shen, X. Xie, S. Gao, and B. O. Guan, “Miniature highly-birefringent microfiber loop with extremely-high refractive index sensitivity,” Opt. Express 20(9), 10180–10185 (2012). [CrossRef] [PubMed]

], MF with elliptical cross section [14

14. H. Xuan, J. Ju, and W. Jin, “Highly birefringent optical microfibers,” Opt. Express 18(4), 3828–3839 (2010). [CrossRef] [PubMed]

], MF drawn from commercial PANDA fiber [15

15. Y. Jung, G. Brambilla, and D. J. Richardson, “Polarization-maintaining optical microfiber,” Opt. Lett. 35(12), 2034–2036 (2010). [CrossRef] [PubMed]

] and MF with a slot inside [17

17. J. L. Kou, F. Xu, and Y. Q. Lu, “Highly birefringent slot-microfiber,” IEEE Photon. Technol. Lett. 23(15), 1034–1036 (2011). [CrossRef]

].

In this paper, we present a simple and effective wrapping-on-a–rod technique for the fabrication of miniaturized compact broadband MF Hi-Bi devices. Without complex and expensive micromachining facility, MF is drawn from standard single-mode fiber and then wrapped on a low-index rod. We both theoretically predict and experimentally demonstrate a MF-based Hi-Bi device by such a technique utilizing a rod-microfiber-air (RMA) structure. The device with compact 3D geometry shows a large birefringence (> 10−3) over 400 nm bandwidth. This compact device presents great potential in sensing and communication applications, as well as lab-on-a-rod devices.

2. Schematic model and theoretical analysis

We numerically investigate the wave guiding properties of the RMA structure. The cross-section of the scheme is shown in Fig. 2
Fig. 2 Cross section and electric field distribution of the RMA structure. Refractive index of different material is labeled in the figure. The green arrow and white dashed line indicates the polarization direction and the boundary between Teflon and air. Inset: electric field distribution of the y-polarized mode. The field is calculated at a wavelength of 1550 nm and rMF = 1 μm.
. Attributed to the asymmetric refractive index distribution in the two orthogonal directions (x and y in Fig. 2), light with different polarization experiences different effective refractive index, which is similar to that of a D-shaped fiber [19

19. Q. Bao, H. Zhang, B. Wang, Z. Ni, C. H. Y. X. Lim, Y. Wang, D. Y. Tang, and K. P. Loh, “Broadband graphene polarizer,” Nat. Photonics 5(7), 411–415 (2011). [CrossRef]

, 20

20. J. L. Kou, Z. D. Huang, G. Zhu, F. Xu, and Y. Q. Lu, “Wave guiding properties and sensitivity of D-shaped optical fiber microwire devices,” Appl. Phys. B 102(3), 615–619 (2011). [CrossRef]

]. And this lays the foundation of the principle employed in this paper. The difference between the effective refractive index is defined as phase birefringence (Bphase), result of which is presented in Fig. 3
Fig. 3 Calculated Bphase of the proposed structure as a function of the radius of the MF and operation wavelength.
. In our calculation range, it is easily found that a smaller rMF and a longer operation wavelength (λ) results in a larger Bphase. As λ decreases, the MF has greater ability to confine the light in the silica region and less evanescent field will penetrate into air or Teflon. It is the same case for increasing rMF, because of which Bphase falls. Moreover, in a wide operation wavelength range (1200 - 1650 nm) and MF diameter range (1.2 - 3 μm), Bphase remains larger than 4 × 10−4 which is the typical value for conventional polarization maintaining fibers [21

21. O. Frazão, J. M. Baptista, and J. L. Santos, “Recent advances in high-birefringence fiber loop mirror sensors,” Sensors (Basel Switzerland) 7(11), 2970–2983 (2007). [CrossRef]

].

3. Experimental fabrication and measurement

First, we use flame-brushing technique to draw the MF from conventional single mode fiber (SMF) which is cost-effective. Prior to the main experiment, we test the polarization properties of the MFs and they show no birefringence. Then, MFs with diameters ranging from 1 μm to 3 μm are wrapped around the PMMA rod (2 mm in diameter) that is pretreated with a coating of Teflon (Teflon® AF 601S1-100-6, a production of DuPont), tens of micrometers in thickness. Due to the high refractive index of PMMA, a thin film of low-index (1.36 @ 1550 nm) Teflon is indispensable in order to prevent the light field from suffering high loss. Because the thickness of the Teflon film is tens of micrometers, little field will penetrate into the PMMA rod which will be neglected in our calculation. To eliminate the field coupling between coils of the MF, distance is kept from coil to coil as shown in the inset of Fig. 4
Fig. 4 Measured transmission spectra of the proposed RMA structure. The blue line is the insertion loss of Sample 1. The green and red line is the transmission of two devices with MF of different diameter (green for Sample 1, dMF = 1.5 μm and red for Sample 2, dMF = 1.7 μm). Inset: optical microscopic picture of one sample. The pink boxes indicate two coils of MF. The distance between the coil is ~100 μm.
. The total insertion loss of the device is about - 5 dB (blue line in Fig. 4), including loss from the MF with a large evanescent field and bending-induce loss. It can be further minimized by optimizing the tapering process and working environment.

Limited by the length of the MF, our samples contain one or two coils of MF and this results in large free spectrum range (FSR). In addition, the radius of the MF is not uniform in the region that wrapped on the rod. Thus, we can only obtain an average group birefringence (Bgroup) of our RMA samples. The results are calculated by Eq. (2) with experimental data from the spectrum.

Bgroup(λ,rMF)λ¯2FSR×L
(2)

L is the length of the MF wrapped around the rod. Solid asterisks in Fig. 5
Fig. 5 Bgroup calculated from FEM method (3D mesh) and that from experimental transmission spectrum (solid asterisks with different colors). Inset: 2D illustration of the experimental (solid asterisks with different colors) and theoretical (blue lines) results of two samples with different radius (left for rMF = 0.9 μm and right for rMF = 1.2 μm). The data is extracted form the 3D mesh.
show Bgroup of our samples with different rMF (measured at the thinnest waist of the MF) calculated from the spectrum. It is clear that a large Bgroup ~10−3 which is more than one order of magnitude than in conventional Hi-Bi fibers is achieved over the measured range and reaches ~4 × 10−4 at ~1415 nm for one particular sample (red asterisks in Fig. 5). In our measured range, a longer wavelength sees a larger Bgroup when rMF > 0.9 μm.

Bgroup=BphaseλdBphasedλ
(3)

4. Conclusions

In this paper, we both theoretically exploit and experimentally realize a new kind MF-based Hi-Bi device which incorporates wrapping a MF around a rod that is pretreated with Teflon coating. This compact and cost-effective device could operate over a broad bandwidth with birefringence higher than 10−3. The fabrication technique of wrapping-on-a-rod is effective and low-cost. More novel and compact lab-on-a-rod devices can be explored by flexible design of rod material or coil profile. Our investigation of it would put insight into the application of MF in future fiber communication, sensing and micro/nano-photonics.

Acknowledgments

This work is supported by National 973 program under contract No. 2012CB921803 and 2011CBA00205, NSFC program No. 11074117 and 60977039, Natural Science Foundation of Jiangsu Province of China under contract No. BK2010247. The authors also acknowledge the support from PAPD and the Fundamental Research Funds for the Central Universities.

References and links

1.

T. Hosaka, K. Okamoto, T. Miya, Y. Sasaki, and T. Edahiro, “Low-loss single polarization fibres with asymmetrical strain birefringence,” Electron. Lett. 17(15), 530–531 (1981). [CrossRef]

2.

M. P. Varnham, D. N. Payne, R. D. Birch, and E. J. Tarbox, “Single-polarization operation of highly birefringent bow-tie optical fibres,” Electron. Lett. 19(7), 246–247 (1983). [CrossRef]

3.

V. Ramaswamy, R. H. Stolen, M. D. Divino, and W. Pleibel, “Birefringence in elliptically clad borosilicate single-mode fibers,” Appl. Opt. 18(24), 4080–4084 (1979). [CrossRef] [PubMed]

4.

A. Kumar, V. Gupta, and K. Thyagarajan, “Geometrical birefringence of polished and D-shape fibers,” Opt. Commun. 61(3), 195–198 (1987). [CrossRef]

5.

R. B. Dyott, J. R. Cozens, and D. G. Morris, “Preservation of polarisation in optical-fibre waveguides with elliptical cores,” Electron. Lett. 15(13), 380–382 (1979). [CrossRef]

6.

X. Chen, M. J. Li, N. Venkataraman, M. T. Gallagher, W. A. Wood, A. M. Crowley, J. P. Carberry, L. A. Zenteno, and K. W. Koch, “Highly birefringent hollow-core photonic bandgap fiber,” Opt. Express 12(16), 3888–3893 (2004). [CrossRef] [PubMed]

7.

J. L. Kou, M. Ding, J. Feng, Y. Q. Lu, F. Xu, and G. Brambilla, “Microfiber-based Bragg gratings for sensing applications: a review,” Sensors (Basel) 12(7), 8861–8876 (2012). [CrossRef] [PubMed]

8.

M. Ding, P. Wang, and G. Brambilla, “Fast-response high-temperature microfiber coupler tip thermometer,” IEEE Photon. Technol. Lett. 24(14), 1209–1211 (2012). [CrossRef]

9.

G. Brambilla, “Optical fibre nanowires and microwires: a review,” J. Opt. 12(4), 043001 (2010). [CrossRef]

10.

J. L. Kou, J. Feng, L. Ye, F. Xu, and Y. Q. Lu, “Miniaturized fiber taper reflective interferometer for high temperature measurement,” Opt. Express 18(13), 14245–14250 (2010). [CrossRef] [PubMed]

11.

J. L. Kou, S. J. Qiu, F. Xu, and Y. Q. Lu, “Demonstration of a compact temperature sensor based on first-order Bragg grating in a tapered fiber probe,” Opt. Express 19(19), 18452–18457 (2011). [CrossRef] [PubMed]

12.

Y. Jung, G. Brambilla, K. Oh, and D. J. Richardson, “Highly birefringent silica microfiber,” Opt. Lett. 35(3), 378–380 (2010). [CrossRef] [PubMed]

13.

L. Sun, J. Li, Y. Tan, X. Shen, X. Xie, S. Gao, and B. O. Guan, “Miniature highly-birefringent microfiber loop with extremely-high refractive index sensitivity,” Opt. Express 20(9), 10180–10185 (2012). [CrossRef] [PubMed]

14.

H. Xuan, J. Ju, and W. Jin, “Highly birefringent optical microfibers,” Opt. Express 18(4), 3828–3839 (2010). [CrossRef] [PubMed]

15.

Y. Jung, G. Brambilla, and D. J. Richardson, “Polarization-maintaining optical microfiber,” Opt. Lett. 35(12), 2034–2036 (2010). [CrossRef] [PubMed]

16.

G. Wang, P. P. Shum, L. Tong, C. M. Li, and C. Lin, “Polarization effects in microfiber loop and knot resonators,” IEEE Photon. Technol. Lett. 22(8), 586–588 (2010). [CrossRef]

17.

J. L. Kou, F. Xu, and Y. Q. Lu, “Highly birefringent slot-microfiber,” IEEE Photon. Technol. Lett. 23(15), 1034–1036 (2011). [CrossRef]

18.

S. C. Rashleigh and R. Ulrich, “High birefringence in tension-coiled single-mode fibers,” Opt. Lett. 5(8), 354–356 (1980). [CrossRef] [PubMed]

19.

Q. Bao, H. Zhang, B. Wang, Z. Ni, C. H. Y. X. Lim, Y. Wang, D. Y. Tang, and K. P. Loh, “Broadband graphene polarizer,” Nat. Photonics 5(7), 411–415 (2011). [CrossRef]

20.

J. L. Kou, Z. D. Huang, G. Zhu, F. Xu, and Y. Q. Lu, “Wave guiding properties and sensitivity of D-shaped optical fiber microwire devices,” Appl. Phys. B 102(3), 615–619 (2011). [CrossRef]

21.

O. Frazão, J. M. Baptista, and J. L. Santos, “Recent advances in high-birefringence fiber loop mirror sensors,” Sensors (Basel Switzerland) 7(11), 2970–2983 (2007). [CrossRef]

22.

R. Ulrich, S. C. Rashleigh, and W. Eickhoff, “Bending-induced birefringence in single-mode fibers,” Opt. Lett. 5(6), 273–275 (1980). [CrossRef] [PubMed]

OCIS Codes
(060.2310) Fiber optics and optical communications : Fiber optics
(060.2420) Fiber optics and optical communications : Fibers, polarization-maintaining
(230.3990) Optical devices : Micro-optical devices

ToC Category:
Fiber Optics and Optical Communications

History
Original Manuscript: September 25, 2012
Revised Manuscript: October 31, 2012
Manuscript Accepted: November 14, 2012
Published: December 7, 2012

Citation
Jun-long Kou, Ye Chen, Fei Xu, and Yan-qing Lu, "Miniaturized broadband highly birefringent device with stereo rod-microfiber-air structure," Opt. Express 20, 28431-28436 (2012)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-27-28431


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. T. Hosaka, K. Okamoto, T. Miya, Y. Sasaki, and T. Edahiro, “Low-loss single polarization fibres with asymmetrical strain birefringence,” Electron. Lett.17(15), 530–531 (1981). [CrossRef]
  2. M. P. Varnham, D. N. Payne, R. D. Birch, and E. J. Tarbox, “Single-polarization operation of highly birefringent bow-tie optical fibres,” Electron. Lett.19(7), 246–247 (1983). [CrossRef]
  3. V. Ramaswamy, R. H. Stolen, M. D. Divino, and W. Pleibel, “Birefringence in elliptically clad borosilicate single-mode fibers,” Appl. Opt.18(24), 4080–4084 (1979). [CrossRef] [PubMed]
  4. A. Kumar, V. Gupta, and K. Thyagarajan, “Geometrical birefringence of polished and D-shape fibers,” Opt. Commun.61(3), 195–198 (1987). [CrossRef]
  5. R. B. Dyott, J. R. Cozens, and D. G. Morris, “Preservation of polarisation in optical-fibre waveguides with elliptical cores,” Electron. Lett.15(13), 380–382 (1979). [CrossRef]
  6. X. Chen, M. J. Li, N. Venkataraman, M. T. Gallagher, W. A. Wood, A. M. Crowley, J. P. Carberry, L. A. Zenteno, and K. W. Koch, “Highly birefringent hollow-core photonic bandgap fiber,” Opt. Express12(16), 3888–3893 (2004). [CrossRef] [PubMed]
  7. J. L. Kou, M. Ding, J. Feng, Y. Q. Lu, F. Xu, and G. Brambilla, “Microfiber-based Bragg gratings for sensing applications: a review,” Sensors (Basel)12(7), 8861–8876 (2012). [CrossRef] [PubMed]
  8. M. Ding, P. Wang, and G. Brambilla, “Fast-response high-temperature microfiber coupler tip thermometer,” IEEE Photon. Technol. Lett.24(14), 1209–1211 (2012). [CrossRef]
  9. G. Brambilla, “Optical fibre nanowires and microwires: a review,” J. Opt.12(4), 043001 (2010). [CrossRef]
  10. J. L. Kou, J. Feng, L. Ye, F. Xu, and Y. Q. Lu, “Miniaturized fiber taper reflective interferometer for high temperature measurement,” Opt. Express18(13), 14245–14250 (2010). [CrossRef] [PubMed]
  11. J. L. Kou, S. J. Qiu, F. Xu, and Y. Q. Lu, “Demonstration of a compact temperature sensor based on first-order Bragg grating in a tapered fiber probe,” Opt. Express19(19), 18452–18457 (2011). [CrossRef] [PubMed]
  12. Y. Jung, G. Brambilla, K. Oh, and D. J. Richardson, “Highly birefringent silica microfiber,” Opt. Lett.35(3), 378–380 (2010). [CrossRef] [PubMed]
  13. L. Sun, J. Li, Y. Tan, X. Shen, X. Xie, S. Gao, and B. O. Guan, “Miniature highly-birefringent microfiber loop with extremely-high refractive index sensitivity,” Opt. Express20(9), 10180–10185 (2012). [CrossRef] [PubMed]
  14. H. Xuan, J. Ju, and W. Jin, “Highly birefringent optical microfibers,” Opt. Express18(4), 3828–3839 (2010). [CrossRef] [PubMed]
  15. Y. Jung, G. Brambilla, and D. J. Richardson, “Polarization-maintaining optical microfiber,” Opt. Lett.35(12), 2034–2036 (2010). [CrossRef] [PubMed]
  16. G. Wang, P. P. Shum, L. Tong, C. M. Li, and C. Lin, “Polarization effects in microfiber loop and knot resonators,” IEEE Photon. Technol. Lett.22(8), 586–588 (2010). [CrossRef]
  17. J. L. Kou, F. Xu, and Y. Q. Lu, “Highly birefringent slot-microfiber,” IEEE Photon. Technol. Lett.23(15), 1034–1036 (2011). [CrossRef]
  18. S. C. Rashleigh and R. Ulrich, “High birefringence in tension-coiled single-mode fibers,” Opt. Lett.5(8), 354–356 (1980). [CrossRef] [PubMed]
  19. Q. Bao, H. Zhang, B. Wang, Z. Ni, C. H. Y. X. Lim, Y. Wang, D. Y. Tang, and K. P. Loh, “Broadband graphene polarizer,” Nat. Photonics5(7), 411–415 (2011). [CrossRef]
  20. J. L. Kou, Z. D. Huang, G. Zhu, F. Xu, and Y. Q. Lu, “Wave guiding properties and sensitivity of D-shaped optical fiber microwire devices,” Appl. Phys. B102(3), 615–619 (2011). [CrossRef]
  21. O. Frazão, J. M. Baptista, and J. L. Santos, “Recent advances in high-birefringence fiber loop mirror sensors,” Sensors (Basel Switzerland)7(11), 2970–2983 (2007). [CrossRef]
  22. R. Ulrich, S. C. Rashleigh, and W. Eickhoff, “Bending-induced birefringence in single-mode fibers,” Opt. Lett.5(6), 273–275 (1980). [CrossRef] [PubMed]

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.

Figures

Fig. 1 Fig. 2 Fig. 3
 
Fig. 4 Fig. 5
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited