Thermal characteristics of high-power long-pulsewidth quasi-CW laser diode arrays

Meadows, B.; Amzajerdian, Farzin; Baker, Nathaniel R.; Sudesh, Vikas; Singh, Upendra N.; Kavaya, Michael J.

doi:10.1117/12.531760

Cited by 21 publications

(15 citation statements)

References 6 publications

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“…The team identified that a better thermo-mechanical design of high power LDA assemblies is critical to the reliable long term operation. Worked with industry for improving the operation lifetime of these critical devises and proposed various solutions [6]. With better manufacturing methods and material selection, the LDA assemblies for 2µm laser application have improved tremendously.…”

Section: Lidar Technology Developmentmentioning

confidence: 99%

2-micron coherent Doppler lidar instrument advancements for tropospheric wind measurement

Petros

Singh

et al. 2014

SPIE Proceedings

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Knowledge derived from global tropospheric wind measurement is an important constituent of our overall understanding of climate behavior [1]. Accurate weather prediction saves lives and protects properties from destructions. High-energy 2-micron laser is the transmitter of choice for coherent Doppler wind detection. In addition to the eye-safety, the wavelength of the transmitter suitably matches the aerosol size in the lower troposphere. Although the technology of the 2-micron laser has been maturing steadily, lidar derived wind data is still a void in the global weather database. In the last decade, researchers at NASA Langley Research Center (LaRC) have been engaged in this endeavor, contributing to the scientific database of 2-micron lidar transmitters. As part of this effort, an in depth analysis of the physics involved in the workings of the Ho: Tm laser systems have been published. In the last few years, we have demonstrated lidar transmitter with over1Joule output energy. In addition, a large body of work has been done in characterizing new laser materials and unique crystal configurations to enhance the efficiency and output energy of the 2-micron laser systems. At present 2-micron lidar systems are measuring wind from both ground and airborne platforms. This paper will provide an overview of the advancements made in recent years and the technology maturity levels attained.

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Section: Lidar Technology Developmentmentioning

confidence: 99%

2-micron coherent Doppler lidar instrument advancements for tropospheric wind measurement

Petros

Singh

et al. 2014

SPIE Proceedings

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“…A fourth, spectrally again well separated emission contribution comes from the mid infrared (MIR). This is thermal emission (Planck's blackbody radiation) and it can be used as a tool for thermal analysis of devices [5][6][7]. There is no need to say that all contributions mentioned are extremely small compared to the primary emission, in particular the lasing.…”

Section: Introductionmentioning

confidence: 98%

Short-wavelength infrared defect emission as probe for degradation effects in diode lasers

Hempel

Tomm

Yue

et al. 2015

Novel in-Plane Semiconductor Lasers XIV

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The infrared emission from 980-nm single-mode high power diode lasers is analyzed in the wavelength range from 0.8 to 7.0 µm. A pronounced short-wavelength infrared (SWIR) emission band with a maximum at 1.3 µm is found to originate from defect states located within the waveguide of the devices. The SWIR intensity is verified to represent a measure of the non-equilibrium carrier concentration in the waveguide, allowing for non-destructive waveguide mapping in spatially resolved detection schemes. The potential of this approach is demonstrated by measuring spatially resolved profiles of SWIR emission and correlating them with mid-wavelength infrared thermal emission along the cavity of devices undergoing repeated catastrophic optical damage. The enhancement of SWIR emission in the damaged parts of the cavity is due to a locally enhanced carrier density in the waveguide and allows for in situ analysis of the damage patterns. Moreover, spatial resolved SWIR measurements are a promising tool for device inspecting even in low-power operation regimes.

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“…Imaging thermography is a novel tool for characterization of thermal properties of electronic devices [2][3][4][5][6][7]. The method was employed for inspection of defective emitters in high power diode laser bar stacks [4].…”

Section: Introductionmentioning

confidence: 99%

Studies of the degradation mechanisms in high-power diode lasers using multi-channel micro-thermography

et al. 2005

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We demonstrate the applicability of imaging thermography for investigations of mechanisms associated with gradual degradation in diode lasers. The introduction of two spectral channels provides the means for separate observation of deep level luminescence and thermal radiation emitted according to Planck's law. In the near IR region we found the signal detected by the camera to be mainly affected by mid-gap deep-level luminescence. An intensity increase of the luminescence signal for an aged diode laser compared to an unaged device is noticed. It can be explained by an increase of deep level defect concentration during the aging. In the mid IR, we mainly encounter thermal radiation, which can be used for the analysis of the thermal properties of devices. In present work the thermal behavior of the device subjected to an aging of 3000 hours is analyzed. A significant increase of device temperature is noticed.

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Thermal characteristics of high-power long-pulsewidth quasi-CW laser diode arrays

Cited by 21 publications

References 6 publications

2-micron coherent Doppler lidar instrument advancements for tropospheric wind measurement

2-micron coherent Doppler lidar instrument advancements for tropospheric wind measurement

Short-wavelength infrared defect emission as probe for degradation effects in diode lasers

Studies of the degradation mechanisms in high-power diode lasers using multi-channel micro-thermography

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