Xingde Zhang

940 nm low beam divergence tapered window laser arrays

Abstract The structures of 940 nm low vertical beam divergence semiconductor lasers grown by molecular beam epitaxy are presented. The high power laser consists of an array of closely spaced tapered waveguides giving lower parallel beam divergence and window structure. The emission wavelength is 939 nm . The FWHM of the far field pattern is 8×30°. The maximum continuous wave (CW) output power of 30 W has been achieved. In the aging tests, the laser arrays have been operating for over 3000 h under the CW condition of 25 W .

High-power 940-nm laser arrays with nonabsorbing facets

In this paper, through the analysis and in consideration of the facts which influence on the ultimate output power of semiconductor laser. we report a novel 940nm semiconductor laser array structure with nonabsorbing facets to avoid the COMD on facets. The 940nm laser wafers are grown by MBE. The lasers were cleaved into cm bars. We have made a new design variant of laser array with nonabsorbing facets and coated high-and low-reflectivity coating (approx.95% and 5%). The emission wavelength of the laser arrays is 939nm. Continuous wave (CW) output power of 15 W has been achieved.

High-power 980-nm laser arrays with nonabsorbing facets

In this letter we report a novel 980 nm semiconductor laser array structure with nonabsorbing facets to avoid the COMD on facets. The 980 nm laser wafers are grown by MBE. Using quantum-well intermixing, we have fabricated nonabsorbing mirrors on the laser arrays facets to resist COMD. The quantum intermixing process involves the deposition of a thin film (200 nm) of sputtered SiO2 and a subsequent high temperature anneal (680 - 760 degrees Celsius). The cm bars are cleaved to lengths of 1 mm and their rear and front nonabsorbing facets are coated respectively with high and low reflectivity dielectric film by electron-beam. The devices are bonded p-side up onto copper heatsinks using indium solder and mounted on a water-cooled stage which is held at 18 degrees Celsius for all experiments. The emission wavelength of the laser arrays is 980 nm. Continuous wave (CW) output power of 8 W has been achieved.

High-power single quantum well array semiconductor lasers

In this paper, through the analysis and in consideration of the facts which influence on the ultimate output power of semiconductor laser, we have designed a laser structure with gradient refraction index separate confinement single quantum well (GRIN-SCH-SQW) and have grown the laser structure by MBE. Moreover we have also fabricated array lasers by broad area structure. The lasers are cleaved into cm bars and coated with high- and low-reflectivity films (approx. 95% and 5%). The QCW output power of the array laser has reached 60 W (100 microsecond(s) , 500 Hz), the peak wavelength of the device is 806 approximately 810 nm.

MBE technology and semiconductor laser material growth

This paper summarizes the technical characteristics and performance of our newly purchased VG V80H MBE system. Our research work on thin film semiconductor laser materials growth on this system has also been presented here, with some discussion on beam flux stability and growth uniformity et al.

Analysis of the thickness measurement of multilayer optical thin films with grazing incident x-ray

The measuring conditions of the thickness of thin films with grazing incident x-ray is explained, and interferential principle and method to measure the thickness of thin films by grazing incident x-ray are discussed and analyzed in the paper. The periodic thickness of the multilayer optical thin films is measured with double-crystal diffractometer at a very small grazing incident angle, the result is satisfactory and measured values is in good agreement with designed values.

Nondestructive measurement of layer thickness in double heterostructures by x-ray double crystal diffraction

In this paper we introduce a method of measuring thin layer thickness using a sandwich structure of the In0.43Ga0.57As0.15P0.85/In0.13Ga0.87As0.75P0.25/In0.43Ga0.57As0.15P0.85 DH with the interference fringes in rocking curve by x-ray double-crystal diffraction.

Single-lobe operation of BA InGaAsP/GaAs SCH SQW lasers

It was observed that a twin-lobe like farfield appeared more obviously with larger stripe width of BA LD, also with increasing injected current, due to much more complicated lateral modes. As a consequence, a single-lobed farfield output of 2.0 W has been realized with BA InGaAsP/GaAs SCH SQW lasers (stripe width 150 um).

808nm Al-free InGaAsP/GaAs SCH SQW lasers fabricated by LPE

In this work, we report Al-free InGaAsP/GaAs separate confinement heterostructure single quantum well structures for lasers emitting at 808 nm are grown by enhanced liquid phase epitaxy. The highest continuous wave output power is 4 W for lasers with coated facts. The differential efficiency is 1.32 W/A. The record characteristic T0 of the laser is estimated to be about 218 K between 10 degree(s)C and 40 degree(s)C from the temperature dependence of the threshold current density Jth.

808-nm high-power semiconductor laser arrays

In this paper, we adopted GaAlAs/GaAs SCH single quantum well wafer, which is grown by MBE, to complete one centimeter monolithic laser arrays, and two array structures were carried out on purpose to obtain cw and quasi-sw laser output respectively. In the experiment, by means of twice photoetching and chemical etching methods were used to isolate active regions to prevent photons from passing from one to another and amplified spontaneous emission. Results were presented for arrays which reach a maximum cw output power of 7 W perfacet and 50 W (200 microsecond(s) , 50 Hz) quasi-sw output, with lasing wavelength 806 - 810 nm.