Laser technology is one of the "Four New Inventions" of the 20th century. It is also the key development direction of the manufacturing revolution of "World Industry 4.0" and "Made in China 2025". With my country's industrial processing, biomedical beauty, and high-speed optical communications With the rapid development of industries such as machine vision and sensing, laser display, and laser lighting, the domestic demand for lasers has grown rapidly. The laser chip is an indispensable core device for the development of the laser industry and the technological core of the entire laser industry chain. However, the laser chip industry in my country started late, and compared with foreign companies, the overall competitiveness is insufficient. In the context of the volatile international political and economic situation and the transformation and upgrading of the domestic manufacturing industry, the localization of laser chips is imminent.
Everbright Huaxin has been insisting on independent research and development and production of high-power laser chips since its establishment in 2012. The 9XXnm 15W, 20W, and 25W single-tube chips that have been launched successively have been tested in the industrial market for many years and have gained widespread trust and recognition in the market.
In order to meet market demand and improve the output power and price-to-power ratio of laser pump sources, Everbright Huaxin has launched a new 9XXnm 28W semiconductor laser chip, which has greatly improved its performance indicators and reliability.
01 Performance indicators have reached the international advanced level
Improve power and efficiency
The output power and efficiency of semiconductor lasers are mainly affected by factors such as laser threshold, slope and high current power rollover. By optimizing the epitaxial structure design, Changguang Huaxin effectively avoids high current rollover and improves the photoelectric conversion efficiency.
1. To raise efficiency
Usually by reducing the doping concentration of the PN junction to lower the threshold and increase the slope, a too low doping concentration will increase the resistance of the PN junction and increase the chip voltage. In order to solve the problem of optimal balance of threshold, slope and voltage, we optimized the asymmetric large optical cavity structure wave, increased the thickness of the waveguide layer, and carefully designed the distribution of doping concentration in different regions of the PN junction to reduce the optical field and high doping. The overlap of free carriers in the impurity confinement layer reduces the absorption loss to ensure that the voltage remains basically unchanged when the threshold is lowered and the slope efficiency is improved, thereby improving the chip efficiency.
2. Avoid high current rollover
The high current bending is mainly due to the decrease of internal quantum efficiency during high current injection. By optimizing the energy band structure of the material near the gain region of the laser structure and improving the PN junction's ability to inject electrons, the quantum efficiency during high current injection is enhanced, and the high current bending phenomenon is effectively avoided.
Improve beam quality, increase brightness
Changguang Huaxin increases the scattering loss of high-order modes, suppresses high-order side modes, improves the beam quality of the laser chip, and improves the brightness through the method of anti-waveguide and microstructure modification engineering. At present, Changguang Huaxin single-tube chips reach 95% of the slow axis. The energy divergence angle is 9°, and the brightness is greater than 80MW/cm2sr.
Through effective treatment and prevention of various influencing factors, the single-tube chip independently developed by Changguang Huaxin has reached commercial power output of 28W, test power reached more than 30W, slow axis 95% energy divergence angle 9°, brightness greater than 80MW/cm2sr, efficiency Reached 65%, a number of performance indicators reached the international leading level.
02 High reliability to meet the needs of the industrial market
While pursuing higher output power and conversion efficiency, meeting the higher requirements of the industrial market for laser life is also the direction of our unremitting efforts.
Cavity surface processing technology is the key to determining the reliability and industrial application of high-power semiconductor laser chips. The increase in the power of laser chips is accompanied by the increase in the junction temperature of the chip and the optical power density of the cavity surface, which puts forward higher requirements for the damage resistance of the cavity surface. On the basis of years of accumulation of key technologies for special cavity surface treatment, Everbright has improved the process level of independent research and development equipment, developed new cavity surface treatment technologies, improved the control quality level of cavity surface treatment, and improved the cavity surface’s ability to resist optical catastrophic damage , To ensure that the 28W high-power laser chip meets the requirements of the industrial market for the life of the laser.
