Random Distributed Feedback Fiber Laser Based on ... - IEEE Xplore

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IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 21, NO. 1, JANUARY/FEBRUARY 2015

Random Distributed Feedback Fiber Laser Based on Combination of Er-Doped Fiber and Single-Mode Fiber Wei Li Zhang, Senior Member, IEEE, Shi Wei Li, Rui Ma, Yun Jiang Rao, Ye Yu Zhu, Zi Nan Wang, Xin Hong Jia, and Jin Li

Abstract—Random distributed feedback fiber laser (RDF-FL) based on combination of Er-doped fiber (EDF) and single-mode fiber (SMF) is proposed in this paper. Through pumping of both the EDF (i.e., 1480 nm pump) and the SMF (i.e., 1455 nm pump), random lasing is obtained. With increase of pump powers, different transitions between chaotic and stable status of the output spectrum are observed. Especially, single-peak random lasing can be obtained under the stable operation regime. Index Terms—Random fiber laser, Raman, Er-doped fiber (EDF), Rayleigh scattering, distributed feedback.

I. INTRODUCTION ECENT years, the studies of fiber lasers have been developed rapidly; many kinds of fiber lasers based on different structures/mechanisms have been reported. In 2010, a novel type of fiber laser, random distributed feedback fiber laser (RDF-FL) based on Raman amplification and distributed Rayleigh scattering (RS) feedback only in a standard single-mode fiber (SMF), was reported by Turitsyn et al. [1], [2]. Since, then, RDF-FLs have been widely studied, due to its simple structure without any “mirrors” and unique output characteristics. These studies related to RDF-FLs include basic emission characteristics [3]– [6], noise and gain optimization [7], [8], high-order and tunable emission [9]–[11], broadband, multi-wavelength, and narrow linewidth outputs [12]–[18]. It is believed that RDF-FL is a good candidate of fiber-optic communication and sensing source, due to its stable output with little thermal sensitivity, wide wavelength tenability, excellent noise and modulation characteristics, spatial incoherence while with a high photonic density of states [19]–[23]. Besides Raman gain, it is also possible to provide gain through active fibers, such as Er-doped fiber (EDF). In [24], EDF was used as passive fiber to absorb Raman-gain-based distributed

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Manuscript received March 9, 2014; revised June 4, 2014 and July 18, 2014; accepted July 25, 2014. Date of publication August 6, 2014; date of current version September 8, 2014. This work was supported by the National Natural Science Foundation of China under Grants 61106045, 61290312, and 61107073, the PCSIRT under Grant IRT1218, the Open Research Fund of State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences under Grant SKLST201302, and the 111 Project under Grant B14039. The authors are with the Key Laboratory of Optical Fiber Sensing and Communications (Education Ministry of China), University of Electronic Science and Technology of China, Chengdu 611731, China (e-mail: wl_zhang@ uestc.edu.cn; [email protected]; [email protected]; yjrao@uestc. edu.cn; [email protected]; [email protected]; [email protected]; [email protected]). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JSTQE.2014.2344050

Fig. 1. Schematic diagram of experimental setup. OSA: optical spectrum analyzer; WDM: wavelength division multiplex; OPM: optical power meter.

feedback random lasing, forming an L-band amplifier. However, the EDF was not used to generate random emission. Random lasing in pure EDF is obtained in [25] and [26], wherein additional point reflector was used because random RS feedback is weak in a short segment of EDF. In this paper, we propose a novel way of realizing a RDF-FL by mixing of EDF and SMF [27]. Through pumping of both the EDF and the SMF, single-peak random lasing can be realized in a completely opened cavity. First, the EDF and SMF combined together can provide hybrid light amplification and considerable RS feedback to support random lasing. Second, combination of EDF and Raman amplifications helps to reduce the requirement of a unique pump for stable random lasing, as well as to reduce (increase) the threshold (output) power of RDF-FL. Taking advantages of the proposed method, random lasing with novel output characteristics, (i.e., stable single-peak random lasing and transitional variation between chaotic and stable states) are observed. In addition, a power balance model including random emission regimes for both the EDF and SMF is introduced. The numerical simulated spectra and output power of the proposed RDF-FL are in good accordance with the experimental results. These studies have significant meanings for fundamental research of random distributed feedback fiber emission, which also provides potential ways of designing new optical communication and sensing sources. II. RESULTS AND DISCUSSIONS A. Experimental Setup The experimental setup is shown schematically in Fig. 1, wherein a symmetry pumping configuration is used. A 1455 nm Raman pump is directed equally into two spools of 50 kmlength standard SMF through a pair of 1455/1550 nm WDMs.

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ZHANG et al.: RANDOM DISTRIBUTED FEEDBACK FIBER LASER BASED ON COMBINATION OF ER-DOPED FIBER AND SINGLE-MODE FIBER

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Fig. 3. Output spectra for different values of P R , when P E = 75 mW. From (a) to (d), P R equals to 251, 794, 2240, and 2818 mW, respectively.

Fig. 2. Output spectra for different value of P E , when P R = 0. (a) and (b) correspond to the case when the two spools of SMF are removed and added, respectively.

A 100 m-length EDF (The type of EDF is EDFC-980-HP, bought from Nufern) is inserted between the two spools of SMF. The EDF is pumped bidirectionally through a pair of 1480/1550 nm WDMs by a 1480 nm pump. Through connection of the WDMs, light generated within the 1550 nm band can pass through the whole structure. The 1480 nm and the 1455 nm pumps cannot go through the 1550 nm ports of the WDMs. Thus, the 1480 nm pump only distributed in the EDF, and the 1455 nm pump only distrusted in the SMFs. B. Experimental Results We first consider the case when the power of EDF pump, PE (i.e., refers to the power of 1480 nm pump that injected into the EDF), is nonzero and the power of Raman pump, PR (i.e., refers to the power of 1455 nm pump that injected into the SMFs), is zero. Fig. 2 shows the output spectra for PR = 0 and different values of PE . In Fig. 2(a), the two spans of SMFs are removed. When PE is small, a typical wideband ASE spectrum of EDF is observed. As PE increases (PE > 220 mW), narrow spikes appear randomly (around the wavelength of 1565 nm) above the ASE spectrum. Fig. 2(b) gives the same plot as Fig. 2(a), except that the two spools of SMF are added. In this case, the EDF performs as gain medium and RS of the SMFs provides random distributed feedback. This is different from [1] and [3], where Raman gain and RS in the SMF work together to initiate random lasing, while in Fig. 2(b) optical gain and random distributed feedback

are separate. The output is also a wideband ASE spectrum when PE is small. However, when PE is larger than a threshold value, random lasing appears. It is obvious that ASE is suppressed and a narrow lasing peak center at ∼1569 nm generates. Besides, additional frequency components exist in the lasing spectrum. This is similar to the chaotic operation regime of SMF-based RDF-FL [1], [3], which might be induced by optical fiber nonlinear effect, such as cascaded stimulated Brillouin scattering (SBS), and four wave mixing etc. [3], [13], [19]. It can be deduced from Fig. 2 that random distributed RS in the SMFs provides feedback round trips of light, which prefers to amplify wavelength components with the highest gain, and thus, launch random lasing. However, no switch from the unstable to the stable operation regime is observed in Fig. 2(b) (in [1], the laser switches from the unstable to the stable operation regime when pump increases), this is because nonlinear effect in the unpumped (i.e., PR = 0) SMFs is limited. The case when both the EDF and Raman pumps are nonzero is discussed in Fig. 3. From Fig. 3(a)–(d), PE = 75 mW, and PR equals to 251, 794, 2240, and 2818 mW, respectively. In [1] and [3], similar experimental setups have been considered except that the EDF and 1480 nm pump in Fig. 1 are removed. In their studies, a transitional operation from chaotic-to-stable status was observed. In our case, two chaotic statuses are observed when PR increases. This could be understood qualitatively when we consider the laser emission of the EDF and the SMF separately. When the Raman pump is turned OFF (PR = 0 mW), the EDF begins to emit chaotic light if PE > 75 mW, as indicated by Fig. 2(b). When value of PR is small, the output is still chaotic, see Fig. 3(a). As PR increases, the chaotic output of EDF is amplified in the SMF and experiences nonlinear effect that switches the laser output from chaotic to stable state [1], [19]. Linewidth of the output spectrum is ∼0.72 nm, see Fig. 3(b). At this stage, PR is still not large enough. Thus, there is no laser emission in the SMFs. The Raman pumped SMFs perform as amplifiers for laser emission from the EDF. When PR increases further, threshold of random lasing in the SMFs is met. The SMFs begin

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Fig. 4. Output spectra for different value of P R , when P E = 1500 mW. From (a) to (d), P R equals to 200, 891, 1778, and 2818 mW, respectively. TABLE I P R RANGE OF THE STABLE AND UNSTABLE OUTPUT

P E (mW) 75 1500

Region of P R when output spectrum is unstable (mW)

Region of P R when output spectrum is unstable (mW)

0∼794, 890∼2818 0∼2180

794∼890, 2818∼3000 2180∼3000

tively. It is observed that the input–output curve moves upwards when PE increases. However, slope efficiencies of the star and circle marked curves are similar. This is because that the output spectrum of random lasing, especially, the emission bandwidth and wavelength range, changes slightly when PE increases. From Fig. 2(b), we can see that the laser begins to emit when PE > 75 mW without the Raman pump (PR = 0). Thus, the threshold value of PR for lasing could not be found when PE > 75 mW. However, to make a comparison, the value of PR when output power reaches 5 mW is defined as the threshold. According to this definition, the threshold value of PR decreases from 344.7 to 325.7 mW when PE increases from 49 to 75 mW. From this point of view, the lasing threshold decreases obviously with increase of PE . We also carry out an additional experiment using Setup I without EDF. The lasing threshold increases to 2000 mW, which is much larger than the case when EDF is added. Besides, two emission peaks [1], [19] around 1555 and 1567 nm appear in the stable regime, while single emission peak is observed when EDF is added. This also verifies the advantage of adding the EDF in our proposed setup, which is useful to make stable single-peak sources with random lasing characteristics such as modeless, spatial incoherence, and temporal coherence [19], [20]. C. Numerical Results The output characteristics (i.e., power distribution, output spectrum) can be analyzed through a power balance model. For our case, both the EDF and the Raman gain based model should be considered. N

N2 = Nt

1+

k =0 N k =0

dPk± dz Fig. 5. Output power versus P R for different values of P E . The star and circle correspond to P E = 75 mW and 1500 mW, respectively.

to emit chaotic light (just like threshold behave of RDF-FL using only SMF [1]). This chaotic emission from the SMFs mixes with emission from the EDF, so the total output becomes chaotic again [see Fig. 3(c)], which is the reason of transition from the stable to the chaotic states in our setup. If PR increases further (PR > 2818 nm), the output spectrum becomes stable again. The linewidth of output spectrum is increased to ∼1.23 nm, see Fig. 3(d). Fig. 4 also shows the variation of output spectrum as a function of PR when PE = 1500 mW. The results are similar to what observed in Fig. 3, except that the range of PR for stable random lasing is changed, see Table I about a further summarized of the output stability. In the stable regimes, the fluctuation of output power is less than 0.1 dB and the fluctuation of peak wavelength is less than 0.02 nm. Fig. 5 shows the output power as a function of PR . The star and circle correspond to PE = 75 mW and 1500 mW, respec-

(P k+ +P k− )α k hυ k ζ (P k+ +P k− )(α k +g k ) hυ k ζ

= ±(αk + gk )

(1)

N2 ± N2 Pk ± 2gk hvk Δvk Nt Nt

∓(αk + lk )Pk± + εk Pk±

(2)

dPk± = ∓ak Pk± ± ηgk (P0+ + P0− )Pk± ± εk Pk∓ dz ∓(1 − η)

N v0 (Pk+ + Pk− )P0± . v k

(3)

k =1

Equations (1) and (2) are the Giles model for the EDF [28], Equation (3) is the Raman-gain-based model [1], [29], [30] for the SMF. In the three equations, “±” represent the right and left -propagating light waves. Subscript k (i.e., an integer) denotes the light waves with the kth wavelength. k = 1 to N, correspond to the random emitting light. In (1) and (2), k = 0 corresponds to the 1480 nm pump, and in (3), k = 0 corresponds to the 1455 nm pump. A control index, η, is introduced in (3). When k = 0, η is set to 0, the equation describes the pump light. When k > 0, η is set to 1, the equation describes the Stokes light. Other parameters, Pk is the light power, N2 is the erbium ion population of the upper energy level, and Nt is the total erbium ion population of the ground state and the upper energy levels.


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Fig. 6. Experimental test values of a k and gk as a function of wavelength (a) for EDF, (b) for SMF. Fig. 8. Power distribution of the pump and the random lasing in the SMF and EDF. In (a) and (c), P E = 75 mW, P R = 2818 mW; In (b) and (d), P E = 1500 mW, P R = 2818 mW.

Fig. 7. Numerical simulated output spectra. The solid and dotted curves correspond to the experimental results of Figs. 3(d) and (d), respectively.

vk is the light frequency, Δvk ( = 2000 GHz) is the noise bandwidth, ζ(= 3.87 × 1015 m−1 s−1 ) is the saturation parameter, and lk (= 0.01 dB/m) is the background loss. The attenuation index, ak , and gain index, gk should be treated separately for EDF (these parameters of EDF are provided by Nufern) and SMF, seeing their values in Fig. 6(a) and (b). The typical Rayleigh scattering coefficient is 10−6 m−1 at 1534 nm in EDF, and is 4.3 ×10−8 m−1 at 1550 nm in SMF. Other values of εk can be approximated through the 1/λ−4 relationship [31]. Using an iteration method [10], (1)–(3) can be solved numerically. In Fig. 5, the two solid curves correspond to the numerically calculated output power as a function of PR . It is seen that the numerical results match well with the experimental results for most values of PR . In numerical simulation, the presence of two linear regimes with increasing Raman pump power are spotted, which corresponds to change of the output spectrum (i.e., change of linewidth of emission). The calculated threshold of PR (the value of PR when output power equals 5 mW) is 307. 5 and 274.0 mW for PE = 49 and 75 mW, respectively. The difference between experimental and numerical result might be caused by the omission of nonlinear effect, especially the SBS effect, in the numerical model. The simulated output spectra in Fig. 7 have a single peak around 1570 nm, which are similar to the experimental result in Fig. 3(d) and Fig. 4(d). As we know, the emission spectrum of RDF-FL is mainly determined by the gain profile. In our

study, the gain is provided by both the EDF and the SMF, the maximum net gain (i.e., gain minus loss) is at ∼1570 nm for the pump powers we considered, so a single lasing peak at ∼ 1570 nm appears. The peak power in Fig. 7 is different from the experimental results, which is because that the coupling loss (mainly caused by optical splitter) of light injected into the optical spectrum analyzer is not considered in the simulation. The slightly discrepancy of peak wavelength between experimental and numerical result is also caused by ignoring of SBS effect in the numerical model. Fig. 8 shows the numerical simulated power distribution of the pump power (PR and PE , the dotted curves) and the power of random emission (Pout , the solid curves). The upper two subplots give the power distribution along the whole structure, while the lower two subplots show the detailed power distribution within the EDF. The arrows indicate propagation directions of light. Fig. 8(a) and (c) [see Fig. 8(b) and (d)] use the same pump values as Fig. 3(d) [see Fig. 4(d)]. It is observed that Pout distribution increases greatly in Fig. 8(b) than in Fig. 8(a), and the Raman pump is depleted faster in Fig. 8(b). This is caused by different pump level of the EDF. Random lasing starts in the EDF when PE > 75 mW, which can perform as the seed light to increase random lasing in the whole structure. From Fig. 8(d), we can see that about 450 mW random emission seed light enters into the right and left SMF spools, while in Fig. 8(c), this value is only about 12 mW. III. CONCLUSION In summary, a novel configuration of RDF-FL through combination of EDF and SMF is studied both experimentally and numerically. In the proposed structure, both the EDF and SMF can provide gain for light amplification, generating random lasing with special characteristics. When only the EDF is pumped, the EDF itself performs as gain medium and the SMF performs as random distributed feedback “mirror,” generating chaotic random lasing. When both the EDF and Raman pumps are used, stable single-peak random lasing is obtained with spectral

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contrast ratio up to 35 dB. This is different from former studies [1] and [3] that only use SMF. Besides, the total pump power for random lasing can be reduced, since the addition of pumped EDF provides not only additional gain but also random emission seed light. These results are useful for fundamental understanding of RDF-FLs, which could also be guides of stable random laser design for specific usage. ACKNOWLEDGMENT The authors would like to thanks Dr. Z. L. Ran at the University of Electronic Science and Technology of China for providing the EDF. REFERENCES [1] S. K. Turitsyn, S. A. Babin, A. E. El-Taher, P. Harper, D. V. Churkin, S. I. Kablukov, J. D. Ania-Castaño´ n, V. Karalekas, and E. V. Podivilov, “Random distributed feedback fiber laser,” Nat. Photon., vol. 4, pp. 231–235, Feb. 2010. [2] S. K. Turitsyn, S. A. Babin, D. V. Churkin, I. D. Vatnik, M. Nikulin, and E. V. Podivilovb, “Random distributed feedback fibre lasers,” Phys. Rep., to be published. [3] D. V. Churkin, S. A. Babin, A. E. El-Taher, P. Harper, S. I. Kablukov, V. Karalekas, J. D. Ania-Castanon, E. V. Podivilov, and S. K. Turitsyn, “Raman fiber lasers with a random distributed feedback based on Rayleigh scattering,” Phys. Rev. A, vol. 82, p. 033828, Sep. 2010. [4] W. L. Zhang, Y. Y. Zhu, Y. J. Rao, Z. N. Wang, X. H. Jia, and H. Wu, “Random fiber laser formed by mixing dispersion compensated fiber and single mode fiber,” Opt. Exp., vol. 21, pp. 8544–8549, Apr. 2013. [5] S. A. Babin, E. I. Dontsova, and S. I. Kablukov, “Random fiber laser directly pumped by a high-power laser diode,” Opt. Lett., vol. 38, pp. 3301–3303, Sep. 2013. [6] A. R. Sarmani, M. H. Abu Bakar, A. A. A. Bakar, F. R. Mahamd Adikan, and M. A. Mahdi, “Spectral variations of the output spectrum in a random distributed feedback Raman fiber laser,” Opt. Exp., vol. 19, pp. 14152– 14159, Jul. 2011. [7] J. Nuño, M. Alcon-name, and J. D. Ania-Castanon, “RIN transfer in random distributed feedback fiber lasers,” Opt. Exp., vol. 20, pp. 27376– 27381, Nov. 2012. [8] X. H. Jia, Y. J. Rao, C. X. Yuan, J. Li, X. D. Yan, Z. N. Wang, W. L. Zhang, H. Wu, Y. Y. Zhu, and F. Peng, “Hybrid distributed Raman amplification combining random fiber laser based 2nd-order and low-noise LD based 1st-order pumping,” Opt. Exp., vol. 21, pp. 24611–24619, Oct. 2013. [9] I. D. Vatnik, D. V. Churkin, S. A. Babin, and S. K. Turitsyn, “Cascaded random distributed feedback Raman fiber laser operating at 1.2 μm,” Opt. Exp., vol. 19, pp. 18486–18494, Sep. 2011. [10] W. L. Zhang, Y. J. Rao, Z. X. Yang, Z. N. Wang, and X. H. Jia, “Low threshold 2nd-order Random lasing of a fiber laser with a half-opened cavity,” Opt. Exp., vol. 20, pp. 14400–14405, Jun. 2012. [11] S. A. Babin, A. E. El-Taher, P. Harper, E. V. Podivilov, and S. K. Turitsyn, “Tunable random fiber laser,” Phys. Rev. A, vol. 84, p. 021805(R), Aug. 2011. [12] T. Zhu, X. Bao, and L. Chen, “A self-gain random distributed feedback fiber laser based on stimulated Rayleigh scattering,” Opt. Commun., vol. 285, pp. 1371–1374, Mar. 2011. [13] M. Peng, X. Bao, and L. Chen, “Observation of narrow linewidth spikes in the coherent Brillouin random fiber laser,” Opt. Lett., vol. 38, pp. 1866– 1868, Jun. 2013. [14] Y. Y. Zhu, W. L. Zhang, Y. J. Rao, Z. N. Wang, and X. H. Jia, “Tunable multi-wavelength fiber laser based on random Rayleigh back-scattering,” IEEE Photon. Technol. Lett., vol. 25, pp. 1559–1561, Aug. 2013. [15] A. E. El-Taher, P. Harper, S. A. Babin, J. D. Ania-Castanon, D. V. Churkin, E. V. Podvilov, and S. K. Turitsyn, “Effect of Rayleigh-scattering distributed feedback on multiwavelength Raman fiber laser generation,” Opt. Lett., vol. 36, pp. 130–132, Jan. 2011. [16] A. M. R. Pinto, O. Frazão, J. L. Santos, and M. Lopez-Amo, “Multiwavelength Raman fiber lasers using Hi-Bi photonic crystal fiber loop mirrors combined with random cavities,” J. Lightw. Technol., vol. 29, no. 10, pp. 1482–1488, May 2011. [17] S. Sugavanam, N. Tarasov, X. Shu, and D. V. Churkin, “Narrow-band generation in random distributed feedback fiber laser,” Opt. Exp., vol. 21, pp. 16466–16472, Jul. 2013.

[18] T. Zhu, F. Y. Chen, S. H. Huang, and X. Y. Bao, “An ultra-narrow linewidth fiber laser based on Rayleigh backscattering in a tapered optical fiber,” Laser Phys. Lett., vol. 10, p. 055110, Apr. 2013. [19] A. A. Fotiadi, “An incoherent fiber laser,” Nat. Photon., vol. 4, pp. 204– 205, Apr. 2010. [20] Z. N. Wang, Y. J. Rao, H. Wu, P. Y. Li, Y. Jiang, X. H. Jia, and W. L. Zhang, “Long-distance fiber-optic point-sensing systems based on random fiber lasers,” Opt. Exp., vol. 20, pp. 17695–17700, Jul. 2012. [21] M. Bravo, M. Fernandez-Vallejo, and M. Lopez-Amo, “Internal modulation of a random fiber laser,” Opt. Lett., vol. 38, pp. 1542–1544, May. 2013. [22] A. M. R. Pinto, M. Lopez-Amo, J. Kobelke, and K. Schuster, “Temperature fiber laser sensor based on a hybrid cavity and a random mirror,” J. Lightw. Technol., vol. 30, no. 8, pp. 1168–1172, Apr. 2012. [23] Y. J. Rao, “Study on fiber-optic low-coherence interferometric and fiber Bragg grating sensors,” Photon. Sens., vol. 1, pp. 382–400, Dec. 2011. [24] M. H. Abu Bakar, F. M. Adikan, and M. A. Mahdi, “Rayleigh-based Raman fiber laser with passive erbium-doped fiber for secondary pumping effect in remote L-band erbium-doped fiber amplifier,” IEEE Photon. J., vol. 4, no. 3, pp. 1042–1050, Jun. 2012. [25] C. Huang, X. Dong, N. Zhang, S. Zhang, and P. Shum, “Multiwavelength Brillouin-erbium random fiber laser incorporating a chirped fiber Bragg grating,” IEEE J. Sel. Topics Quantum Electron., vol. 21, no. 5, pp. 0902405-1–0902405-5, Sep./Oct. 2014. [26] P. Zhang, T. Wang, Q. Jia, X. Liu, M. Kong, S. Tong, and H. Jiang, “A novel fiber laser based on Rayleigh scattering feedback with a half-opened cavity,” in Proc. SPIE, vol. 8906, pp. 890617-1–890617-6, 2013. [27] W. L. Zhang, S. W. Li, Y. J. Rao, Y. Y. Zhu, Z. N. Wang, and J. Li, “Highly stable single-wavelength and broadband random fiber lasers,” in Proc. 23rd Int. Conf. Opt. Fiber Sens., Santander, U.K., Jun. 06, 2014, pp. 9157–418. [28] C. R. Giles, “Modeling erbium-doped fiber amplifiers,” J. Lightw. Technol., vol. 9, no. 2, pp 271–283, Feb. 1991 [29] I. D. Vatnik, D. V. Churkin, and S. A. Babin, “Power optimization of random distributed feedback fiber lasers,” Opt. Exp., vol. 20, pp. 28033– 28038, Dec. 2012. [30] I. D. Vatnik and D. V. Churkin, “Modeling of the spectrum in a random distributed feedback fiber laser within the power balance modes,” Proc. SPIE, vol. 9135, pp. 91351Z-1–91351Z-7, May 1, 2014. [31] S. V. Smirnov and D. V. Churkin, “Modeling of spectral and statistical properties of a Random distributed feedback fiber laser,” Opt. Exp., vol. 21, pp. 21236–21241, Sep. 2013.

Wei Li Zhang (M’13–SM’13) received the B.Eng. and Ph.D. degrees in communication engineering from Southwest Jiaotong University, Leshan, China, in 2003 and 2008, respectively. From September 2000 to October 2010, he was working as a Research Fellow in the School of EEE, Nanyang Technological University, Singapore. He has been with the University of Electronic Science and Technology of China as an Associated Professor since November 2010. His research interests include optical fiber lasers, semiconductor microcavity lasers, and surface-plasmon physics. He has authored/coauthored more than 90 papers published in refereed professional journals and national and international conferences and has filled five patents. His doctoral dissertation was awarded the “Excellent Doctoral Dissertation of Sichuan Province” and the nomination award of “National Excellent Doctoral Dissertation of China.” He got the “2007’s Jeme Tien Yow Special Prize of Science and Technology.” He was selected the backbone members of “Changjiang Scholars and Innovative Research Team in University of China.” He owned the “2013 New-professional Academic Award” of University of Electronic Science and Technology of China. Dr. Zhang is the Editor-in-Chief Assistant of Photonic Sensors an Editorial Board Member of Progress in Condensed Matter Physics, and a Member of the OSA.

Shi Wei Li is currently working toward the master’s degree in optical engineering in the University of Electronic Science and Technology of China, Chengdu, China. His research interests include fiber lasers and optical communication.

Rui Ma is currently working toward the Ph.D. degree in optical engineering in the University of Electronic Science and Technology of China, Chengdu, China. His research interests include novel lasers and fiber sensors.


Yun Jiang Rao received the Ph.D. degree in optoelectronic instrumentation from Chongqing University, Shapingba, China, in 1990. His Ph.D. study was on the development of the first fully-automatic optical fiber fusion splicing machine in China. From 1991 to 1992, he joined the Department of Electronics, University of Strathclyde, U.K., as a Postdoctoral Research Fellow. From 1992 to 1999, he was with the Physics Laboratory, University of Kent at Canterbury, U.K., as a Research Fellow/Senior Research Fellow. He was a Chang-Jiang Chair Professor at the Department of Optoelectronic Engineering, Chongqing University and established the Optical Fiber Technology Group with strong support from the Ministry of Education of China during 2000–2004. Since 2005, he has been the Dean of School of Communication and Information Engineering, University of Electronic Science and Technology of China and also as a Chang-Jiang Chair Professor in optical engineering. His recent research interests include fiber-optic sensors and systems, fiber-optic devices for communications, micro and nano optical fibers, microstructured optical fibers. He holds 24 Chinese patents and has published several book chapters as well as more than 300 papers in international journals and conference proceedings. In 2000, he was awarded the National Science Fund for Distinguished Young Scientists by the National Nature Science Foundation of China. He won the Wang-Da-Heng Optics Award of the Optical Society of China in 2001 and the National Achievement Award for Returned Overseas Scientists in 2003. In 2004, he led the New Century National Hundred, Thousand and Ten Thousand Talent Project (State level). Prof. Rao is a Fellow of SPIS and Senior Member of the OSA. He is the TPC cochair/member of the International Conferences on Optical Fiber Sensors and the Chairman of Asia-Pacific Optical Sensors Conferences. He is an Associate Editor of the IEEE/OSA JOURNAL OF LIGHTWAVE TECHNOLOGY, Optics and Laser Technology (Elsevier) and also serves as the Editor-in-Chief of Photonic Sensors (Springer).

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Zi Nan Wang received the Ph.D. degree in electromagnetic field and microwave technology from the Beijing University of Posts and Telecommunications, Beijing, China, in 2009. He was with School of Applied and Engineering Physics, Cornell University, as a Postdoctoral Research Associate during 2009–2010. He joined the University of Electronic Science and Technology of China, Chengdu, China, as an Associate Professor in 2010. His research interests include nonlinear fiber optics, distributed fiber sensing, and optical communications. He has first-authored or coauthored more than 30 papers published in refereed professional journals and national and international conferences, and filled eight patents. He was selected the backbone members of “Changjiang Scholars and Innovative Research Team in University of China.” He is the member of OSA.

Xin Hong Jia received the Ph.D. degree in communication engineering from the University of Electronic Science and Technology of China, Chengdu, China, in 2013. His research interests include nonlinear fiber optics and distributed fiber sensing.

Jin Li is currently working toward the master’s degree in optical engineering in University of Electronic Science and Technology of China, Chengdu, China. Her research interests include nonlinear fiber optics and distributed fiber sensing.

Ye Yu Zhu received the B.Eng. degree in optical engineering from Chongqing University, Shapingba, China, in 2010. He is currently working toward the master’s degree in optical engineering in University of Electronic Science and Technology of China, Chengdu, China. His research interests include fiber lasers and fiber sensors.