A novel vertical-cavity surface-emitting laser (VCSEL) with single mode, high-power, low divergence, and temperature stability is presented. The most prominent structural feature of the device is that the high optical loss region is formed by an anti-phase surface relief above the top Distributed Bragg Reflectors (DBRs) and the light-emitting aperture is ringshaped with larger region. The simulation results show the device with 15μm oxide aperture and 5μm width ring light emitting region achieves stable single-higher-order transverse mode emission with a side mode suppression ratio (SMSR) of more than 80dB. The maximum continuous-wave (CW) single mode power is up to 15.2 mW and far-field divergence angle (FWHM) is lower than 4.5°. Moreover, the VCSEL maintains CW single mode emission up to a record high temperature of 450K.
A large size vertical-cavity surface-emitting laser (VCSEL) with multiple concentric ring apertures (MCRA) is investigated. Compared with a typical VCSEL with the same outer dimension, the 804nm VCSEL with MCRA has maximal continuous wave(CW) light output power 0.23 W which is about 3 times that of a typical device. The novel laser also exhibits a stable single-lobed far field pattern with low beam divergence angle, which is suitable for free-space optical communication and optical interconnection applications.
In this paper, the new structure of 980nm VCSEL was designed and fabricated in order to
improve thermal problem and photo-electricity characteristic. From the point of view reduced
equivalent resistance, P-side electrode was designed as intra-cavity contact structure. The VCSEL with
conventional flip bottom emission structure and intra-cavity contact structure have been fabricated
with the same aperture and tested comparatively. the new structure has a differential resistance of 21Ω,
but the conventional structure has a differential resistance of 25.5Ω. The tested results showed that this
new-type structure VCSEL is expected to improve the thermal characteristics of the device and the
Wet etching process is a key technology in fabrication of VCSEL and their array in order to
improve opto-electric characteristics of high-power VCSEL, devices with multi-ring distribution hole
VCSEL is fabricated. The H3PO4 etching solution was used in the wet etching progress and etching
rate is studied by changing etching solution concentration and etching time. The optimum
technological conditions were determined by studying the etching morphology and etching depth of
the GaAs-VCSEL. The tested results show that the complete morphology and the appropriate depth
can be obtained by using the concentration ratio of 1:1:10, which can meet the requirements of
GaAs-based VCSEL micro- structure etching process.
Wet-oxidation experiments in a nitrogen environment at high temperatures are conducted to improve the photoelectricity performance of the 850nm VCSELs. It is very important to accurately control the oxidation aperture.We have carried out upon the wafer of VCSELs with the same structure by changing the furnace temperature and oxidation time, then micro-probe analyses have been examined at different oxidation depth by scanning electron microscope (SEM) and by X-ray. Oxidation products are examined at different oxidation depths of oxidation layer and each component content is analyzed, we get the law of the wet-oxidation. The oxidation process thermal stability and precision can be improved by lowering the oxidation temperature and prolonging the oxidation time.
In order to study the output characteristics of 808nm vertical cavity surface emitting laser(VCSEL) with large aperture at different temperature, 808nm VCSEL with 500μm emitting diameter are fabricated with Reticular Electrode Structure(RES). Lasing wavelength, optical power and the threshold current are measured by changing the temperature of heat sink. And an output power of 0.42W is achieved at 1.3A at room temperature under continuous wave operation. The central wavelength is 803.32nm, and the full width at half maximum is 0.16nm, the temperature shift is 0.06nm/℃, the thermal resistance is 0.098℃/mW. The testing results show that 808nm VCSEL with large aperture is good temperature characteristic.