title: Switchable and tunable multiple-channel erbium-doped fiber laser using graphene-polymer nanocomposite and asymmetric two-stage fiber Sagnac loop filter.
abstract: A high-performance multiple-channel erbium-doped fiber laser (EDFL) is proposed and experimentally demonstrated, using graphene-polymer nanocomposite as a multiwavelength equalizer and an asymmetric two-stage polarization-maintaining fiber (PMF) Sagnac loop as a flexible comb filter. At first, the filtering characteristics of the PMF Sagnac loop filter (SLF) are investigated. Both theoretical and experimental results show that it can provide a flexibly switchable and tunable comblike filtering. Then, the two-stage PMF SLF is inserted into a graphene-assisted EDFL cavity for generating multiwavelength oscillation. The extreme-high third-order optical nonlinearity of graphene is exploited to suppress the mode competition of the EDFL, and a stable multiple-channel lasing is observed. By carefully adjusting the polarization controllers in the two-stage PMF SLF, not only can the lasing-line number per channel be switchable between single and multiple wavelengths, but also the wavelength spacing in the triple-wavelength condition can be tunable. In the case of triple wavelengths per channel, up to 12 wavelengths with four channels stable oscillations can be achieved. The multiple-channel EDFL can keep a high extinction ratio of >40 dB and a narrow linewidth of <0.01 nm.
authors.affiliation: Institute of Optoelectronic Technology, Department of Electronic Engineering, Xiamen University, Xiamen 361005, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhou
authors.forename: Zhengqian
authors.initials: Z
authors.lastname: Luo
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Cai
authors.forename: Chenchun
authors.initials: C
authors.lastname: Ye
authors.forename: Huiying
authors.initials: H
authors.lastname: Xu
authors.forename: Jinzhang
authors.initials: J
authors.lastname: Wang