Fibre-Format Photonic Source Based on Efficient Frequency Doubling of Continuous-Wave Erbiu
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ZHANG Shuang-Gen( )1,2 , YAO Jiang-Hong( )1,2 , SHI Qing( 1 1 LI Yong-Nan( ) , TU Cheng-Hou( ) , GUO Wen-Gang(
1 2
)1 , LIU Yan-Ge( ) , LU Fu-YunPhysical Science, Nankai University, Tianjin 300071 The Key Laboratory of Weak Light Nonlinear Photonics (Ministry of Education), Nankai University, Tianjin 300457 3 Institute of Modern Optics, Nankai University, Tianjin 300071
PACS: 42. 55. Wd, 42. 65. Ky Researchers have extensively investigated efficient up-conversion into the visible utilizing periodically poled materials were carried out so far.[1−4] However, the choice of the traditional solid-state or diode laser sources limit the range of accessible wavelength and generally contributed to single-frequency conversion. With the recent progress in fibre laser technology, high power level, wide spectrum range, tunable capability can be realized both in CW, quasi-CW, and pulsed regimes.[5,6] Therefore, fibre sources are becoming ideal pump sources on the route to new range, environmentally stable, and fibre-integrated radiation. Early work on frequency doubling of fibre-format in PPKTP has been demonstrated.[7−10] In additional setups, efficient second harmonic generation (SHG) processes from mode-locked Er-doped fibre laser in PPLN,[11,12] resulted in several mW of output power at wavelength of 771 nm and 777 nm. With such approach, some domestic work has been initially carried out. Zhu Xiao-zheng et al reported the fibrebase SHG scheme using PPLN at 1064 nm, and obtained the SHG spectrum under different operation temperature.[13] In this Letter, an efficient photonic device based on fibre-format scheme of frequency doubling at 1550 nm band is demonstrated in bulk PPLN crystal with practical powers. Continuous-wave SHG output power up to 90.6 mW with the single-pass conversion efficiency about 14.7% is obtained. The spectrum width of 2.1 nm and the temperature width of 1.7◦ C are obtained in the tuning performance experiment. The schematic diagram showing the frequency doubling process is depicted in Fig. 1. The pump source was built around a master oscillator-power amplifier (MOPA) architecture, which includes two parts. One is the ring fibre structure based on a common single-clad Er-doped fibre and the other is the Er/Ybdoped double-clad fibre amplifier pumped backward. The output signal power from master source was boosted in a double-clad fibre amplifier pumped by a stack of 980 nm diode lasers. Driven at full power, the MOPA system could produce maximum output power of 2.18 W over a tunable wavelength range 1535–1570 nm. The emission spectra from single-clad Er-doped fibre and the spectra amplified by Er/Ybdoped double-clad fibre are shown in Figs. 2 and 3.
∗ Supported by the National Natural Science Foundation of China under Grant No 60677013, the Specialized Research Fund for the Doctoral Programme of Higher Education of China under Grant No 20060055021, the National Basic Research Programme of China under Grant No 2006CB921703. ∗∗ Email: lufy@ c 2008 Chinese Physical Society and IOP Publishing Ltd
CHIN.PHYS.LETT.
Vol. 25, No. 8 (2008) 2873
Fibre-Format Photonic Source Based on Efficient Frequency Doubling of Continuous-Wave Erbium-Fibre Laser Amplifier ∗
(Received 31 March 2008)
We demonstrate a compact photonic device based on efficient and wavelength-tunable doubling of an all fibreformat source. Quasi-phase-matched second-harmonic generation in periodically poled lithium niobate is used to generate 90.6 mW at 775.9 nm with a single-pass conversion efficiency of 14.7%. A tuning bandwidth of 2.1 nm and a tuning temperature range of 150.6 ± 1.7◦ C can be achieved. The Er-doped seed fibre source is amplified by a clad-pumped Er3+ /Yb3+ -codoped fibre laser with a high output power up to 2.18 W over a tunable wavelength range from 1535 nm to 1570 nm.
2874
ZHANG Shuang-Gen et al.
Vol. 25
optical performance was evaluated with the cw fibre source as described above in a simple single-pass SHG scheme. Under co-focusing condition, the focusing 2 beam waist (Fig. 4) reads[14] L = 2πw0 n1 /λ1 , where w0 is the beam waist; L is the interaction length; n1 is the fundamental wave refractive index, and λ1 is the fundamental wavelength. To use the largest nonlinear ω ω 2ω coefficient d33 , Type-1 Ez + Ez → Ez (e + e → e) phase matching was employed using the Wollaston prism. The fibre beam was polarized along the z -axis, loosely focused into the PPLN sample with the beam waist diameter about 35 µm, and the focusing conditions within the crystal was optimized with a 60 mm focal lens. The end faces of sample was polished but without anti-reflection coating. The PPLN sample was placed inside a temperature-controlled oven (HC photonics), in which the operation temperature can be controlled up to 200◦ C with an accuracy of 0.1◦ C, allowing for precise thermo-optic tuning.
1 2
)1 , LIU Yan-Ge( ) , LU Fu-YunPhysical Science, Nankai University, Tianjin 300071 The Key Laboratory of Weak Light Nonlinear Photonics (Ministry of Education), Nankai University, Tianjin 300457 3 Institute of Modern Optics, Nankai University, Tianjin 300071
PACS: 42. 55. Wd, 42. 65. Ky Researchers have extensively investigated efficient up-conversion into the visible utilizing periodically poled materials were carried out so far.[1−4] However, the choice of the traditional solid-state or diode laser sources limit the range of accessible wavelength and generally contributed to single-frequency conversion. With the recent progress in fibre laser technology, high power level, wide spectrum range, tunable capability can be realized both in CW, quasi-CW, and pulsed regimes.[5,6] Therefore, fibre sources are becoming ideal pump sources on the route to new range, environmentally stable, and fibre-integrated radiation. Early work on frequency doubling of fibre-format in PPKTP has been demonstrated.[7−10] In additional setups, efficient second harmonic generation (SHG) processes from mode-locked Er-doped fibre laser in PPLN,[11,12] resulted in several mW of output power at wavelength of 771 nm and 777 nm. With such approach, some domestic work has been initially carried out. Zhu Xiao-zheng et al reported the fibrebase SHG scheme using PPLN at 1064 nm, and obtained the SHG spectrum under different operation temperature.[13] In this Letter, an efficient photonic device based on fibre-format scheme of frequency doubling at 1550 nm band is demonstrated in bulk PPLN crystal with practical powers. Continuous-wave SHG output power up to 90.6 mW with the single-pass conversion efficiency about 14.7% is obtained. The spectrum width of 2.1 nm and the temperature width of 1.7◦ C are obtained in the tuning performance experiment. The schematic diagram showing the frequency doubling process is depicted in Fig. 1. The pump source was built around a master oscillator-power amplifier (MOPA) architecture, which includes two parts. One is the ring fibre structure based on a common single-clad Er-doped fibre and the other is the Er/Ybdoped double-clad fibre amplifier pumped backward. The output signal power from master source was boosted in a double-clad fibre amplifier pumped by a stack of 980 nm diode lasers. Driven at full power, the MOPA system could produce maximum output power of 2.18 W over a tunable wavelength range 1535–1570 nm. The emission spectra from single-clad Er-doped fibre and the spectra amplified by Er/Ybdoped double-clad fibre are shown in Figs. 2 and 3.
∗ Supported by the National Natural Science Foundation of China under Grant No 60677013, the Specialized Research Fund for the Doctoral Programme of Higher Education of China under Grant No 20060055021, the National Basic Research Programme of China under Grant No 2006CB921703. ∗∗ Email: lufy@ c 2008 Chinese Physical Society and IOP Publishing Ltd
CHIN.PHYS.LETT.
Vol. 25, No. 8 (2008) 2873
Fibre-Format Photonic Source Based on Efficient Frequency Doubling of Continuous-Wave Erbium-Fibre Laser Amplifier ∗
(Received 31 March 2008)
We demonstrate a compact photonic device based on efficient and wavelength-tunable doubling of an all fibreformat source. Quasi-phase-matched second-harmonic generation in periodically poled lithium niobate is used to generate 90.6 mW at 775.9 nm with a single-pass conversion efficiency of 14.7%. A tuning bandwidth of 2.1 nm and a tuning temperature range of 150.6 ± 1.7◦ C can be achieved. The Er-doped seed fibre source is amplified by a clad-pumped Er3+ /Yb3+ -codoped fibre laser with a high output power up to 2.18 W over a tunable wavelength range from 1535 nm to 1570 nm.
2874
ZHANG Shuang-Gen et al.
Vol. 25
optical performance was evaluated with the cw fibre source as described above in a simple single-pass SHG scheme. Under co-focusing condition, the focusing 2 beam waist (Fig. 4) reads[14] L = 2πw0 n1 /λ1 , where w0 is the beam waist; L is the interaction length; n1 is the fundamental wave refractive index, and λ1 is the fundamental wavelength. To use the largest nonlinear ω ω 2ω coefficient d33 , Type-1 Ez + Ez → Ez (e + e → e) phase matching was employed using the Wollaston prism. The fibre beam was polarized along the z -axis, loosely focused into the PPLN sample with the beam waist diameter about 35 µm, and the focusing conditions within the crystal was optimized with a 60 mm focal lens. The end faces of sample was polished but without anti-reflection coating. The PPLN sample was placed inside a temperature-controlled oven (HC photonics), in which the operation temperature can be controlled up to 200◦ C with an accuracy of 0.1◦ C, allowing for precise thermo-optic tuning.
