The 9xxnm laser chip has been upgraded! The research results were published in international famous journals and highly recognized by experts!

Release time:

2023-06-15 13:19

Recently, the R&D team led by Dr. Guowen Yang of dogain Laser has made new progress in the field of high power semiconductor lasers, achieving a breakthrough in both output power and electro-optical conversion efficiency. 230μm strip width 915nm single tube device has an output power of 48.5W at 48A/30℃/CW, and the peak electro-optical conversion efficiency (PCE) is as high as 72.6%, the PCE at 30W power point is greater than 67%, and the PCE at 35W is still as high as 64.5%! The PCE at 30W power point is greater than 67%, and the PCE at 35W output is still as high as 64.5%!


The research result "48 W continuous-wave output from a high-efficiency single emitter laser diode at 915 nm" was published in the international famous academic journal "Photonics Technology Letters", and was highly recognized by the reviewers: "The achievement of the PCE was highly appreciated. The results of the study "48 W continuous wave output from a high efficiency single emitter laser diode at 915 nm" were published in Photonics Technology Letters, a prestigious international academic journal.


Research paper published in Photonics Technology Letters


01Applications and Background

High-power 9xx-nm semiconductor lasers (LDs) are widely used in industrial processing as fiber laser pump sources and direct semiconductor laser light sources. Due to the wide absorption band of Yb-doped fiber in the 915nm band, it is especially suitable for working in a wide range of temperature conditions and has advantages in reducing the temperature control cost of laser systems, so 915nm semiconductor lasers are an important choice for fiber laser pump sources. With the rapid development of the industrial processing field, the demand for power enhancement of fiber lasers is very urgent. Therefore, it also puts forward more stringent requirements on the performance, reliability and stability of semiconductor laser chips. Improving the power and efficiency of 9xx-nm semiconductor lasers has important application and economic value.


        Absorption spectrum of ytterbium-doped (Yb) fiber


02Technical Difficulties

1. the problem of power limitation due to thermal rollover at very high output optical power.

2. the problem of optical catastrophe damage (COMD) at the cavity surface under extremely high power density and current density operating conditions.

3. the design challenges of chips requiring low loss, low voltage, high internal quantum efficiency and low divergence angle, but with conflicting constraints and contradictions between parameters.

4. the challenge of growing high quality epitaxial materials with low defect density, low impurity density, and high repetitive stability.


03Research results

To address the goal of high power output, simulations based on the laser chip characteristic parameters were first performed to analyze the effects of internal quantum efficiency and internal optical loss on slope efficiency, as well as the effects of threshold current and slope efficiency on output power. The results show that achieving high internal quantum efficiency with low internal losses is the key to obtain high power output. Through novel structure design, high-quality epitaxial growth, and refined process preparation, a performance record level of internal loss as low as 0.31 cm-1 and internal quantum efficiency as high as 96% was obtained. Based on this, the 230-μm strip-width single-tube device was prepared to achieve the highest output power of up to 48.5 W at 48 A, 30°C, CW!


Power-current test characteristics curve of 10 single-tube semiconductor lasers at 30℃, CW


The test results of the chip under continuous operating conditions at room temperature of 25℃ show that the maximum electro-optical conversion efficiency at 14A is as high as 72.6%! The PCE at 30W output is greater than 67%, and the PCE at 35W output is still as high as 64.5%. Based on the above technology enhancement, the newly launched 230μm strip width 30W and 35W single tube products have been verified by customers and started mass production.


Power, voltage and electro-optical conversion efficiency curves with current at 25℃, CW

      Long-term reliability test curves for 55 devices


04The main series of products formed

Based on the research results of the above technologies, we have developed a series of single-tube products of 880/915/945/975nm.




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