High-power single emitters for fiber laser pumping across 8xx nm-9xx nm wavelength bands

Levy, Moshe; Rappaport, Noam; Klumel, Genadi; Shamay, Moshe; Tessler, Renana; Yanson, D.A.; Cohen, Shalom; Don, Yaroslav; Karni, Yoram

doi:10.1117/12.909016

Cited by 6 publications

(4 citation statements)

References 8 publications

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“…By using an asymmetric waveguide structure, we reported [5] a very low optical loss of under 0.5 cm -1 enabling wall-plug efficiencies (WPE) in excess of 60% .…”

Section: Epitaxial Designmentioning

confidence: 97%

“…Historically, standalone Gen 1 emitters were qualified for 12 A operation as reported in [5], where we obtained a mean time to failure (MTTF) of over 150k hours as summarized in Table 3. In designing the lifetest conditions for the Gen 2 wafer devices which featured a broadened vertical spot on the facet, we intended to maximize the optical load on the facet by ramping the drive current to 16 A and lowering the base temperature to T = 25°C.…”

Section: Single Emitter Reliabilitymentioning

confidence: 99%

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Low-NA fiber laser pumps powered by high-brightness single emitters

Yanson

Levy

Peleg

et al. 2015

High-Power Diode Laser Technology and Applications XIII

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Fiber laser manufacturers demand high-brightness laser diode pumps delivering optical pump energy in both a compact fiber core and narrow angular content. A pump delivery fiber of a 105 µm core and 0.22 numerical aperture (NA) is typically used, where the fiber NA is under-filled to ease the launch of laser diode emission into the fiber and make the fiber tolerant to bending. At SCD, we have developed high-brightness NEON multi-emitter fiber-coupled pump modules that deliver 50 W output from a 105 µm, 0.15 NA fiber enabling low-NA power delivery to a customer's fiber laser network.Brightness-enhanced single emitters are engineered with ultra-low divergence for compatibility with the low-NA delivery fiber, with the latest emitters delivering 14 W with 95% of the slow-axis energy contained within an NA of 0.09. The reduced slow-axis divergence is achieved with an optimized epitaxial design, where the peak optical intensity is reduced to both lessen filamentation within the laser cavity and reduce the power density on the output facet thus increasing the emitter reliability.The low mode filling of the fiber allows it to be coiled with diameters down to 70 mm at full operating power despite the small NA and further eliminates the need for mode-stripping at fiber combiners and splices downstream from our pump modules. 50W fiber pump products at 915, 950 and 975 nm wavelengths are presented, including a wavelengthstabilized version at 976 nm.

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“…By using an asymmetric waveguide structure, we reported [5] a very low optical loss of under 0.5 cm -1 enabling wall-plug efficiencies (WPE) in excess of 60% .…”

Section: Epitaxial Designmentioning

confidence: 97%

Section: Single Emitter Reliabilitymentioning

confidence: 99%

Low-NA fiber laser pumps powered by high-brightness single emitters

Yanson

Levy

Peleg

et al. 2015

High-Power Diode Laser Technology and Applications XIII

Self Cite

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“…In this study, we have used our high-power single emitters at 980 nm manufactured for single and multi-emitter fiber pump modules [5]. The 4-mm long InGaAs/AlGaAs laser chips emit up to 19 W thermally-limited power from a 90 μm aperture, with their power and wall-plug efficiency curves given in Figure 1(a).…”

Section: Single Emitter Performance and Reliabilitymentioning

confidence: 99%

Multi-spectral investigation of bulk and facet failures in high-power single emitters at 980 nm

et al. 2013

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Reliable single emitters delivering >10W in the 9xx nm spectral range, are common building blocks for fiber laser pumps. As facet passivation techniques can suppress or delay catastrophic optical mirror damage (COMD) extending emitter reliability into hundreds of thousands of hours, other, less dominant, failure modes such as intra-chip catastrophic optical bulk damage (COBD) become apparent. Based on our failure statistics in high current operation, only ~52% of all failures can be attributed to COMD. Imaging through a window opened in the metallization on the substrate (n) side of a p-side down mounted emitter provides valuable insight into both COMD and COBD failure mechanisms.We developed a laser ablation process to define a window on the n-side of an InGaAs/AlGaAs 980nm single emitter that is overlaid on the pumped 90µm stripe on the p-side. The ablation process is compatible with the chip wire-bonding, enabling the device to be operated at high currents with high injection uniformity.We analyzed both COMD and COBD failed emitters in the electroluminescence and mid-IR domains supported by FIB/SEM observation. The ablated devices revealed branching dark line patterns, with a line origin either at the facet center (COMD case) or near the stripe edge away from the facet (COBD case). In both cases, the branching direction is always toward the rear facet (against the photon density gradient), with SEM images revealing a disordered active layer structure. Absorption levels between 0.22eV -0.55eV were observed in disordered regions by FT-IR spectroscopy. Temperature mapping of a single emitter in the MWIR domain was performed using an InSb detector. We also report an electroluminescence study of a single emitter just before and after failure.

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“…For our commercial 6000W laser system, which is designed to target metal brazing applications, six of such modules are stacked and operated at around 120A, wavelength beam-combined and finally coupled into a 600µm delivery fiber providing a BPP of around 50mm*mrad. The laser diode failure rate can be accelerated in reference to its target operating condition (T op , P op , I op ) by the laser diode junction temperature (T j ), the drive current (I) and the light output power (P) as described by Equation 1 [6], where E a is the activation energy and k B is the Boltzmann constant (Arrhenius law). "m" and "n" are the acceleration factors for the injection current and the light output power, respectively.…”

Section: Direct Diode Laser Module Performances and Reliability Testmentioning

confidence: 99%

Advancements in high-power high-brightness laser bars and single emitters for pumping and direct diode application

Jiang

Xiong

et al. 2015

High-Power Diode Laser Technology and Applications XIII

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We have continuously optimized high fill factor bar and packaging design to increase power and efficiency for thin disc laser system pump application. On the other hand, low fill factor bars packaged on the same direct copper bonded (DCB) cooling platform are used to build multi-kilowatt direct diode laser systems. We have also optimized the single emitter designs for fiber laser pump applications. In this paper, we will give an overview of our recent advances in high power high brightness laser bars and single emitters for pumping and direct diode application. We will present 300W bar development results for our next generation thin disk laser pump source. We will also show recent improvements on slow axis beam quality of low fill factor bar and its application on performance improvement of 4-5 kW TruDiode laser system with BPP of 30 mm*mrad from a 600 µm fiber. Performance and reliability results of single emitter for multiemitter fiber laser pump source will be presented as well.

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High-power single emitters for fiber laser pumping across 8xx nm-9xx nm wavelength bands

Cited by 6 publications

References 8 publications

Low-NA fiber laser pumps powered by high-brightness single emitters

Low-NA fiber laser pumps powered by high-brightness single emitters

Multi-spectral investigation of bulk and facet failures in high-power single emitters at 980 nm

Advancements in high-power high-brightness laser bars and single emitters for pumping and direct diode application

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