Wavelength spacing tunable dual-wavelength single-longitudinal-mode fiber ring laser based on fiber Bragg gratings

A wavelength spacing tunable dual-wavelength single-longitudinal-mode fiber ring laser is presented by employing separated fiber Bragg gratings. By using a saturable-absorption-induced grating filter and a hybrid gain medium formed by a semiconductor optical amplifier and an erbium-doped fiber amplifier, stable single-longitudinal-mode lasing is achieved at room temperature. Wavelength spacing of the proposed fiber laser can be tuned in a range from 0.1 to 1.3 nm.     

Tunable single-longitudinal-mode Ytterbium all fiber laser with saturable-absorber-based auto-tracking filter

A broadband tunable, single-longitudinal-mode (SLM) Ytterbium fiber laser with unpumped Ytterbium-doped Sagnac loop is proposed and demonstrated experimentally. The unpumped Ytterbium-doped Sagnac loop is employed as a saturable absorber based auto-tracking filter to ensure single-longitudinal-mode oscillation. And a tunable band pass optical filter with large tuning range is applied to achieve broadband tuning ability. With 1-m Ytterbium-doped fiber as the gain medium, the SLM operation is achieved with over 60-nm wavelength tuning range at 160-mW pump power. The laser is very stable with output power of about 3 dBm and optical signal to noise ratio of higher than 50 dB in all the 60-nm tuning range.     

基于无源三环复合子腔的2050 nm波段单纵模掺铥光纤激光器EI北大核心CSCD

提出了一种在2050 nm波段的基于新型无源三环复合子腔的单纵模掺铥光纤激光器。对所提出的新型复合三环子腔滤波器进行了详细的理论分析,可以通过调整其有效自由光谱范围和透射带宽实现超窄带滤波,从而确保激光器的单纵模运行。所搭建激光器的输出波长为2048.48 nm,光信噪比为70 dB,100 min内的波长和功率波动分别小于0.02 nm和0.453 dB。实验结果表明,激光器可以工作在稳定的单纵模输出状态。该激光器有望用于自由空间光通信或用作多普勒激光雷达的高功率光纤激光器的种子源。     

Employing external injection-locked Fabry-Perot laser scheme for mm-wave generation

We propose and experimentally investigate a 170 GHz band millimeter-wave source employing an external dual-mode-locked Fabry-Perot laser diode (FP-LD) with a 1.38 nm mode-spacing. Two continuous-wave (CW) lights are aligned to inject the corresponding modes of FP-LD to generate dual-beat-mode output. The proposed dual-mode laser is not only stable, but also has single-longitudinal-mode (SLM) output characteristics. Moreover, the relationship between two external-injected wavelengths is also analyzed for the dual-wavelength output.     

A Pre－lasing Reliable Dynamic Filter Single－longitudinal－mode Q－switched Laser

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Single-longitudinal-mode dual-wavelength fiber ring laser by incorporating variable saturable absorbers and feedback fiber loops

A single-longitudinal-mode dual-wavelength fiber ring laser is proposed and demonstrated experimentally by introducing feedback fiber loops and a variable saturable absorber in a fiber ring cavity. A dynamic ultra-narrow bandpass filter is formed by the combined interactions of cascaded fiber Bragg gratings, feedback fiber loops and low-pumped erbium-doped fiber. Both ultra-narrow bandpass filter and accurate control for the cavity length are not required for the single-longitudinal-mode performance. The proposed scheme offers a possibility of generating terahertz waves by photomixing the lasing wavelengths in a high-speed photodetector.     

Using Saganc loop of optical-injected semiconductor laser scheme for stable and continuous CW wavelength-tuning

We propose and experimentally investigate a stable and continuous wavelength-tuning laser structure by using self-injected Fabry-Perot laser diode (FP-LD) with Saganc loop scheme. In this proposed laser scheme, the lasing wavelength can be tuned in the range of 1526.20 to 1549.75 nm with tuning-step of 1.30 nm in single-longitudinal-mode (SLM) output. Here, the maximum and minimum output powers are −7.4 and −17.0 dBm, and their corresponding side-mode suppression ratios are 52.0 and 52.8 dB/0.05 nm, respectively. Moreover, to achieve the continuous wavelength tuning, we can also adjust the temperature of FP-LD for wavelength shifting.     

Frequency-tunable 500-mW continuous-wave all-solid-state single-frequency source in the blue spectral region

A compact source of stable cw single-frequency radiation at 473 nm has been realized by second-harmonic generation of a diode-pumped miniature Nd:YAG ring laser operating on the (4)F(3/2) - (4)I(9/2) laser transition. By use of potassium niobate (KNbO(3)), single-longitudinal-mode output powers of 500 mW cw with high stability and maximum optical-to-optical conversion efficiencies >81% are achieved. An external semimonolithic cavity permits mode-hop-free frequency tuning of blue radiation over as much as 20 GHz.     

稳定可调谐的单纵模多环形腔掺铒光纤激光器

提出了一种多环形腔(MRC)结构的稳定可调的单纵模(SLM)掺铒光纤激光器,多环形腔结构由双环形有源腔和两个次级无源腔组成.这种激光器是利用光纤法布里珀罗可调滤波器(FFP-TF)以及光学光栅滤波器(OGF)两种滤波器和多环形腔结构相结合来共同选模.可实现波长调节范围为1528～1565 nm,在整个波长调节范围内边模抑制比大于44.53 dB,在1554 nm附近边模抑制比可以达到最大值51.18 dB, 输出功率为-8.84 dBm,通过应用多环型腔结构,激光器的输出很稳定,在18 min的观察时间内,中心波长的变化小于0.02 nm,输出功率的变化小于0.04 dBm,实现了稳定且可调谐的单纵模输出.     

Single-longitudinal-mode erbium-doped fiber laser with the fiber-Bragg-grating-based asymmetric two-cavity structure

We present a simple and stable single-longitudinal-mode (SLM) erbium-doped fiber linear-type laser. It consists of three FBGs directly written in a photosensitive erbium-doped fiber (PEDF) to form asymmetric two cavities with different cavity lengths, which can effectively increase the longitudinal mode spacing and suppress mode hopping, experimentally compared with symmetric two cavities and single-cavity structures. The stable SLM operation is conveniently achieved without accurate control of cavity length, and the laser linewidth of less than 5 kHz is acquired.     

Stable single-longitudinal-mode fiber laser using PM FBG F-P etalon and PM fiber saturable absorber

we present a stable and high efficiency single-longitudinal-mode (SLM) fiber ring laser by using polarization-maintaining fiber Bragg grating Fabry-Perot (PM FBG F-P) etalon combining PM fiber saturable absorber. The PM FBG F-P etalon, which is directly fabricated in hydrogen-loaded PM fiber, is used as reflector and mode-selecting component to reduce the longitudinal-mode density greatly. Meanwhile, a segment un-pumped PM Er³⁺-doped fiber (EDF) serves as saturable absorber to suppress mode hopping and ensure the stable SLM operation. Stable SLM laser output at 1550.4 nm with linewidth of 2.0 kHz is observed. Laser output power is 43.7 mW for a pump power of 148 mW, optical-optical efficiency is 29.5% and signal-to-noise ratio (SNR) is larger than 55 dB.     

环形腔2.05μm单谐振KTP晶体光参量振荡器研究

针对大气CO_2浓度探测差分吸收激光雷达的应用需求,采用稳定环形腔和模式匹配设计,搭建了一套单纵模1 064nm激光泵浦的单谐振KTP晶体光参量振荡器,获得高斜率转换效率、基横模的2.05μm波长纳秒激光脉冲输出.在8字形环形行波稳定腔中,将2块II类相位匹配KTP晶体以走离补偿方式放置,在20Hz重复频率下,当泵浦单脉冲能量达到11mJ时,获得了单脉冲能量为2.4mJ的2.05μm信号光输出,脉宽约24ns,斜率效率达到53%.2.05μm信号光光束质量因子在x、y方向分别为1.3和1.2.     

Generation of watt-level single-longitudinal-mode output from cladding-pumped short fiber lasers

We generate as much as 1.6 W of continuous-wave 1550 nm single-longitudinal-mode output from a cladding pumped Er-Yb codoped phosphate fiber laser. This power is to our knowledge among the highest in single-longitudinal-mode fiber lasers. The narrowband fiber Bragg grating output coupler is demonstrated to be an effective element for providing the single-longitudinal-mode selection.     

Switchable single-longitudinal-mode dual-wavelength erbium-doped fiber ring laser incorporating a semiconductor optical amplifier

We propose and demonstrate a novel single-longitudinal-mode (SLM) dual-wavelength erbium-doped fiber ring laser incorporating a semiconductor optical amplifier. The SOA biased in its low-gain regime greatly reduces the gain competition of the two wavelengths. The stable SLM operation is guaranteed by a passive triple-ring cavity and a fiber Fabry-Perot filter. The dual-wavelength output with a 40 GHz wavelength spacing is switchable in the range of 1533-1565.4 nm.     

Tunable microwave signal generation based on an Opto-DMD processor and a photonic crystal fiber

Frequency-tunable microwave signal generation is proposed and experimentally demonstrated with a dual-wavelength single-longitudinal-mode （SLM） erbium-doped fiber ring laser based on a digital Opto-DMD processor and four-wave mixing （FWM） in a high-nonlinear photonic crystal fiber （PCF）. The high-nonlinear PCF is employed for the generation of the FWM to obtain stable and uniform dual-wavelength oscillation. Two different short passive sub-ring cavities in the main ring cavity serve as mode filters to make SLM lasing. The two lasing wavelengths are electronically selected by loading different gratings on the Opto-DMD processor controlled with a computer. The wavelength spacing can be smartly adjusted from 0.165 nm to 1.08 nm within a tuning accuracy of 0.055 nm. Two microwave signals at 17.23 GHz and 27.47 GHz are achieved. The stability of the microwave signal is discussed. The system has the ability to generate a 137.36-GHz photonic millimeter signal at room temperature.     

Single-longitudinal-mode erbium-doped fiber laser with novel scheme utilizing fiber Bragg grating inside ring cavity

In this paper, we experimentally investigate a single-longitudinal-mode (SLM) S-band erbiumdoped fiber (EDF) laser with dualring scheme using a S-band fiber Bragg grating (FBG) inside the gain cavity to restrict the lasing mode. The proposed laser is constructed by two-ring cavities serving as the mode filters. The FBG inside the proposed laser scheme can retrieve the SLM operation. Moreover, the output performance of the proposed fiber laser is also analyzed and discussed.     

Single-longitudinal-mode fiber ring laser using fiber grating-based Fabry-Perot filters and variable saturable absorbers

A single-longitudinal-mode (SLM) fiber ring laser is demonstrated by incorporating a fiber Bragg grating (FBG)-based Fabry-Perot (F-P) filter and a variable saturable absorber in a fiber ring cavity. An ultra-narrow bandpass filter is established by the combined mode filtering of the FBG-based F-P filter and the variable saturable absorber. No accurate control for cavity length is required, and stable single longitudinal-mode operation without mode hopping is conveniently achieved.     

High power single-longitudinal-mode Ho:YLF unidirectional ring laser based on a composite structure of acousto-optic device and wave plate

We report a unidirectional single-longitudinal-mode Ho:YLF ring laser. An acousto-optic modulator and two half-wave plates were used to enforce the Ho:YLF ring laser in a unidirectional operation. The single-longitudinal-mode output power could reach 3.73 W successfully when the incident pump power was 16.4 W. The corresponding slope efficiency was 27.1%. The wavelength of the single-longitudinal-mode Ho:YLF ring laser was 2063.8 nm. The M² factor was 1.12. The results illustrated that the single-longitudinal-mode output power could be further enhanced by increasing the radio frequency power of the acousto-optic modulator.     

A 2 μm Single-Longitudinal-Mode Ho:GdVO4 CW Laser

Journal of Russian Laser Research - We demonstrate a single-longitudinal-mode Ho:GdVO4 continuous-wave (CW) laser at 2048.6 nm. We achieved excellent single-longitudinal-mode performance using a...     

2041.3 nm/2054.6 nm simultaneous dual-wavelength single-longitudinal-mode Tm,Ho:YVO<Subscript>4</Subscript> microchip laser

We report a single-longitudinal-mode CW diode-pumped Tm, Ho: YVO₄ microchip laser emitting at both 2041.3 and 2054.6 nm. At each wavelength, the laser has a single longitudinal mode. The total single-longitudinal-mode output power reaches 185 mW with 20.4% optical conversion efficiency at 905 mW incident pump power.