scispace - formally typeset
Search or ask a question
Author

Jianfeng Wu

Bio: Jianfeng Wu is an academic researcher from University of Arizona. The author has contributed to research in topics: Fiber laser & Laser. The author has an hindex of 7, co-authored 19 publications receiving 585 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: A 64 W fiber laser at 1.9 microm with a slope efficiency of 68% with respect to the launching pump power at 800 nm was demonstrated in a one-end pump configuration using a piece of 20 cm long newly developed thulium-doped germanate glass double-cladding single-mode fiber.
Abstract: A 64 W fiber laser at 1.9 μm with a slope efficiency of 68% with respect to the launching pump power at 800 nm was demonstrated in a one-end pump configuration using a piece of 20 cm long newly developed thulium-doped germanate glass double-cladding single-mode fiber. A quantum efficiency of 1.8 was achieved. An output laser power of 104 W at 1.9 μm was demonstrated from a piece of 40 cm long fiber with a dual-end pump configuration.

186 citations

Journal ArticleDOI
TL;DR: Efficient operation of diode-pumped single-frequency fiber lasers at wavelengths from 1740 to 2017 nm has been demonstrated by using a very short piece of newly developed single-mode active fiber, i.e., heavily thulium-doped germanate glass fiber.
Abstract: Efficient operation of diode-pumped single-frequency fiber lasers at wavelengths from 1740 to 2017 nm has been demonstrated by using a very short piece of newly developed single-mode active fiber, i.e., heavily thulium-doped germanate glass fiber. At 1893 nm, the single-frequency fiber laser has a pump threshold of 30 mW, a slope efficiency of 35%, and maximum output power of 50 mW with respect to the launched power of single-mode pump diodes at 805 nm. To the best of our knowledge, this is the highest lasing efficiency achieved in single-frequency fiber lasers operating near 2 μm. Frequency noise of the single-frequency fiber laser at 1893nm has been characterized and compared with that of single-frequency fiber lasers at 1 and 1.55 μm.

111 citations

Journal ArticleDOI
Abstract: Er3+ doped Na2O–Nb2O5–TeO2 (NNT) glasses suitable for making optical waveguide devices has been fabricated and characterized. Intense 1.53 μm infrared fluorescence and green upconversion luminescence were observed under 975 nm diode laser and 798 nm laser excitation. The optical absorption, the Judd–Ofelt parameters and the spontaneous transition probabilities have been measured and calculated. The quantum efficiency of 1.53 μm emission band is proved to be ~100%. The maximum emission cross-section is 1.02×10−20 cm2 at 1.533 μm, and it is more than 30% higher than the values in silicate and phosphate glasses. Under 798 nm excitation, strong green and weak red upconversion luminescence was observed at room temperature. The 546 nm green band shows a broad full-width at half-maximum of 16 nm. Intense and broad green upconversion fluorescence in Er3+ doped NNT glass can be used in colour display, undersea communication and infrared sensor. High concentration of Na2O is a benefit to developing waveguide device from the glass.

99 citations

Journal ArticleDOI
TL;DR: In this paper, an efficient fiber laser operating near 2 /spl mu/m was reported, which corresponds to a quantum efficiency of 1.79, indicating that each pump photon leads to near 1.8 excited Tm/sup 3+/ ions.
Abstract: We report an efficient fiber laser operating near 2 /spl mu/m. The glass for the fiber is germanate that is highly doped with thulium. The effect of cross relaxation energy transfer between thulium ions as observed from emission spectrum of the glass samples results in the laser having a very high slope efficiency of 58% with respect to launched power. This corresponds to a quantum efficiency of 1.79, indicating that each pump photon leads to near 1.8 excited Tm/sup 3+/ ions.

75 citations

Journal ArticleDOI
TL;DR: In this paper, a single mode microsphere laser at 2μm was demonstrated from a highly thulium doped tellurite glass micro-sphere, which was fabricated and characterized to choose the material with the highest pump efficiency.
Abstract: A single mode microsphere laser at 2μm is demonstrated from a highly thulium doped tellurite glass microsphere. Glass samples with various doping concentrations are fabricated and characterized to choose the material with the highest pump efficiency. The laser wavelength is redshifted from the emission peak of thulium ions at 1800 nm due to the different mode distribution inside the microsphere. The laser line width (full width at half maximum) is measured as 115 MHz.

62 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this article, a review summarizes the different rare-earth cations and host materials used in mid-infrared fiber laser technology, and discusses the future applications and challenges for the field.
Abstract: Fibre lasers in the mid-infrared regime are useful for a diverse range of fields, including chemical and biomedical sensing, military applications and materials processing. This Review summarizes the different rare-earth cations and host materials used in mid-infrared fibre laser technology, and discusses the future applications and challenges for the field.

974 citations

Journal ArticleDOI
TL;DR: In this paper, the thermal and viscosity properties of tellurite and germanate glass for fiber fabrication and compare the linear loss for near and mid-IR device engineering.

363 citations

Journal ArticleDOI
TL;DR: Godard et al. as discussed by the authors reviewed the main technologies, restricted to continuous-wave (CW) and nanosecond pulsed sources emitting in the 2-12 µm range, and discussed the pros and cons of these technologies in the context of several selected applications.

355 citations

Book ChapterDOI
01 Feb 2010
TL;DR: The wavelength range around 2 μm which is covered by the laser systems described in this chapter is part of the so called "eye safe" wavelength region which begins at about 1.4 μm as discussed by the authors.
Abstract: The wavelength range around 2 μm which is covered by the laser systems described in this chapter is part of the so called “eye safe” wavelength region which begins at about 1.4 μm. Laser systems that operate in this region offer exceptional advantages for free space applications compared to conventional systems that operate at shorter wavelengths. This gives them a great market potential for the use in LIDAR and gas sensing systems and for direct optical communication applications. The favourable absorption in water makes such lasers also very useful for medical applications. As it can be seen in figure 1, there is a strong absorption peak near 2 μm which reduces the penetration depth of this wavelength in tissue to a few hundred μm.

344 citations

Journal ArticleDOI
TL;DR: In this paper, a short review on different types of niobates, namely columbite and rare earth, and the relation of the properties of these materials with niobium oxides is presented.

338 citations