Validar: a testbed for advanced 2-micron Doppler lidar

Koch, Grady J.; Petros, Mulugeta; Barnes, Bruce W.; Beyon, Jeffrey Y.; Amzajerdian, Farzin; Yu, Jirong; Kavaya, Michael J.; Singh, Upendra N.

doi:10.1117/12.542116

Cited by 24 publications

(18 citation statements)

References 14 publications

(15 reference statements)

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“…Lasers operating at ~2-µm have already proved to be good sources of coherent radiation used in medicine, spectroscopy, gas sensing, direct energy systems or nonlinear frequency conversion systems [e.g., [1][2][3][4][5][6][7]. Particularly, Tm 3+ -doped fiber lasers (TDFLs) have attracted great attention of many research groups recently.…”

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confidence: 99%

A 2 ?m, gain-switched Tm-doped fiber laser and amplifier system with output average power of 9 W at 50 kHz

Świderski

Michalska

Pichola

et al. 2013

Photon. Lett. Poland

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Abstract-We demonstrate a gain-switched thulium-doped fiber laser and amplifier system (TDFL&A) operating at a wavelength of 1994.7nm. A pulsed fiber Master Oscillator Power Amplifier (MOPA) at 1.55μm was used to gain-switch the Tm fiber laser via in-band pumping. In the next step, the gain-switched pulses were amplified in a cladding-pumped Tm-doped fiber amplifier pumped by up to 30 W at 793nm. For the pulse repetition frequency (PRF) of 100kHz, the laser system delivered the maximum average output power as high as 9.03W with a slope efficiency of 36.4%. For the PRF of 50 kHz, stable 25-ns pulses with energy of 0.18mJ corresponding to a peak-power of 6.8kW were achieved. The performance of the laser system is described.Lasers operating at ~2-µm have already proved to be good sources of coherent radiation used in medicine, spectroscopy, gas sensing, direct energy systems or nonlinear frequency conversion systems [e.g., 1-7]. Particularly, Tm 3+ -doped fiber lasers (TDFLs) have attracted great attention of many research groups recently. They seem to be especially suitable for producing 2-µm laser radiation due to: (1) strong absorption spectrum that has good overlap with the emission spectrum of commercially available 793-nm laser diodes, (2) the energy-level structure of Tm 3+ ions providing the quantum efficiency of a laser close to 200% through the cross relaxation process and (3) wide tunability over the emission band spanning from ~1.7 to 2.1µm. TDFLs can effectively generate continuous wave (CW) output power (exceeding even 1 kW level [8]) as well as pulses of a nanosecond [9][10] or picosecond [11][12] width.Many applications require 2-µm pulses of short, usually on the nanosecond scale, duration with appropriate kW peak power and generated at high (>10 kHz) PRF. Such values can be directly achieved by simple Q-switching of laser losses [e.g., 13-15]. However, in the case of all Qswitched lasers the pulse width is dependent on repetition rate, which may be a problem for some applications, especially for those where a high degree of control on pulse parameters is needed. Therefore, an alternative method of pulse operation seems to be gain-switching where pulse operation is realized by laser gain on/off switching via pump power modulation [12,16]. In particular, fast gain-switching, together with in-band * E-mail: jswiderski@wat.edu.pl pumping, can provide stable 2-µm pulses of short duration at PRF of a few tens of kHz [17]. Furthermore, a gain-switching technique offers simple laser geometry (there is no need to use additional in-cavity components, which is convenient for ensuring an all-fiber configuration) and a narrow bandwidth of laser output (by using fiber Bragg gratings).To realize fast gain switching of TDFLs effectively, they can be pumped by short (<200ns) pulses at a wavelength of ~1.5µm [17][18] or ~1.9µm [19]. This allowed obtaining 2-µm pulses as short as 10ns [17] and pulses with energy of up to 1.3mJ [16]. This paper presents results on a 2-µm, fast gain switched, narrow-band Tm 3+ -doped ...

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confidence: 99%

A 2 ?m, gain-switched Tm-doped fiber laser and amplifier system with output average power of 9 W at 50 kHz

Świderski

Michalska

Pichola

et al. 2013

Photon. Lett. Poland

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“…Tm-doped fiber lasers are promising in applications such as remote sensing [1,2], gas sensing [3,4,2], eye-safe lidar [5,6] and optical parametric oscillation (OPO) to generate mid-infrared lasers [7,8]. Most of these applications require narrow linewidth operation of the laser system [9,10].…”

Section: Introductionmentioning

confidence: 99%

A highly efficient 57 pm Tm-doped fiber laser with two multimode fiber Bragg gratings

Tao

Huang

et al. 2013

Laser Phys.

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An LD-clad pumped Tm-doped fiber laser is built with two multimode double-clad fiber Bragg gratings (FBGs) to generate narrow linewidth output around 2 µm. The slope efficiency of this laser system is 43.1% with respect to the launched pump power, corresponding to a quantum efficiency of 109%, which means that at least 9% of the doped thulium ions take part in the two-for-one cross relaxation process. Exploiting two multimode FBGs and wrapping the fiber onto an aluminum spool, a single peak narrow linewidth spectrum is generated. A 3 dB linewidth of 57 pm centering at 1996.2 nm is obtained at an output of 3.6 W.

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“…This diode pumped injection seeded MOPA has a transform limited line width and diffraction limited beam quality. Although it is primarily designed as a wind Doppler lidar [1], with minimal modification it can be used as a Differential Absorption Lidar (DIAL) instrument for CO 2 sensing. In addition to being used as a field instrument, the laser will also be used as an engineering design tool for evaluating essential wind lidar parameters for a long term flight instrument.…”

Section: Introductionmentioning

confidence: 99%

High-energy, 2µm laser transmitter for coherent wind LIDAR

Singh

Kavaya

et al. 2017

International Conference on Space Optics — ICSO 2008

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A coherent Doppler lidar at 2µm wavelength has been built with higher output energy (300 mJ) than previously available. The laser transmitter is based on the solid-state Ho:Tm:LuLiF, a NASA Langley Research Center invented laser material for higher extraction efficiency. This diode pumped injection seeded MOPA has a transform limited line width and diffraction limited beam quality. NASA Langley Research Center is developing coherent wind lidar transmitter technology at eye-safe wavelength for satellite-based observation of wind on a global scale. The ability to profile wind is a key measurement for understanding and predicting atmospheric dynamics and is a critical measurement for improving weather forecasting and climate modeling. We would describe the development and performance of an engineering hardened 2µm laser transmitter for coherent Doppler wind measurement from ground/aircraft/space platform. INTRODUCTION 2µm solid-state lasers are the primary choice for coherent Doppler wind detection. As wind lidars, they are used for wake vortex and clear air turbulence detection providing air transport safety. In addition, 2µm lasers are one of the candidates for CO 2 detection lidars. The rich CO 2 absorption line around 2µm, combined with the long upper state life of time, has made Ho based 2µm lasers a viable candidate for CO 2 sensing DIAL instrument. As a transmitter for a coherent wind lidar, this laser has stringent spectral line width and beam quality requirements. Among the rare-earth ions lasers operating at 2µm region, Ho doped crystals show high enough gain cross-sections for effective high energy amplification. To accommodate the efficient diode laser pumping, Tm ions were added to absorb the conventional diode laser pump energy at 780-795nm.

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Validar: a testbed for advanced 2-micron Doppler lidar

Cited by 24 publications

References 14 publications

A 2 ?m, gain-switched Tm-doped fiber laser and amplifier system with output average power of 9 W at 50 kHz

A 2 ?m, gain-switched Tm-doped fiber laser and amplifier system with output average power of 9 W at 50 kHz

A highly efficient 57 pm Tm-doped fiber laser with two multimode fiber Bragg gratings

High-energy, 2µm laser transmitter for coherent wind LIDAR

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