Vertical cavity surface emitting laser(VCSELs)as the ideal light source for rubidium(Rb)and cesium(Cs)atomic clocks is analyzed for its mode and polarization control.We fabricated three kinds of shapes:triangular,elli...Vertical cavity surface emitting laser(VCSELs)as the ideal light source for rubidium(Rb)and cesium(Cs)atomic clocks is analyzed for its mode and polarization control.We fabricated three kinds of shapes:triangular,elliptic,and circular oxidation apertures which also have different sizes.We formed three different shape oxide apertures by wetoxidation with 36μm-39μm circular mesa.Our results show that triangular oxidized-VCSEL has the advantages of mode and polarization selection over elliptic and circular oxide apertures.When triangular oxide-confined VCSELs emit in single mode,the measured side mode suppression ratio(SMSR)is larger than 20 d B and orthogonal polarization suppression ratio achieves 10 d B.Resonant blueshift of VCSELs with triangular and elliptic apertures is observed with the decrease of aperture size.展开更多
The influence ot oxidation aperture on the output characteristics ot the circularly symmetric vertical-cavity-surtaceemitting laser(VCSEL) structure is investigated.To do so,VCSELs with different oxide aperture sizes ...The influence ot oxidation aperture on the output characteristics ot the circularly symmetric vertical-cavity-surtaceemitting laser(VCSEL) structure is investigated.To do so,VCSELs with different oxide aperture sizes are simulated by the finite-difference time-domain(FDTD) method.The relationships among the field distribution of mode superposition,mode wavelength,output spectra,and far-field divergence with different oxide apertures are obtained.Further,VCSELs respectively with oxide aperture sizes of 2.7 μm,4.4 μm,5.9 μm,7 μm,8 μm,9 μm,and 18.7 μm are fabricated and characterized.The maximum output power increases from 2.4 mW to 5.7 mW with oxide aperture increasing from 5.9 μm to 9 μm.Meanwhile,the wavelength tuning rate decreases from 0.93 nm/mA to 0.375 nm/mA when the oxide aperture increases from 2.7 μm to 9 μm.The thermal resistance decreases from 2.815℃/mW to 1.015℃/mW when the oxide aperture increases from 4.4 μm to 18.7μm.It is demonstrated theoretically and experimentally that the wavelength spacing between adjacent modes increases with the augment of the injection current and the spacing becomes smaller with the oxide aperture increasing.Thus it can be reported that the aperture size can effectively reduce the mode overlaying but at the cost of the power decreasing and the wavelength tuning rate and thermal resistance increasing.展开更多
文摘Vertical cavity surface emitting laser(VCSELs)as the ideal light source for rubidium(Rb)and cesium(Cs)atomic clocks is analyzed for its mode and polarization control.We fabricated three kinds of shapes:triangular,elliptic,and circular oxidation apertures which also have different sizes.We formed three different shape oxide apertures by wetoxidation with 36μm-39μm circular mesa.Our results show that triangular oxidized-VCSEL has the advantages of mode and polarization selection over elliptic and circular oxide apertures.When triangular oxide-confined VCSELs emit in single mode,the measured side mode suppression ratio(SMSR)is larger than 20 d B and orthogonal polarization suppression ratio achieves 10 d B.Resonant blueshift of VCSELs with triangular and elliptic apertures is observed with the decrease of aperture size.
文摘The influence ot oxidation aperture on the output characteristics ot the circularly symmetric vertical-cavity-surtaceemitting laser(VCSEL) structure is investigated.To do so,VCSELs with different oxide aperture sizes are simulated by the finite-difference time-domain(FDTD) method.The relationships among the field distribution of mode superposition,mode wavelength,output spectra,and far-field divergence with different oxide apertures are obtained.Further,VCSELs respectively with oxide aperture sizes of 2.7 μm,4.4 μm,5.9 μm,7 μm,8 μm,9 μm,and 18.7 μm are fabricated and characterized.The maximum output power increases from 2.4 mW to 5.7 mW with oxide aperture increasing from 5.9 μm to 9 μm.Meanwhile,the wavelength tuning rate decreases from 0.93 nm/mA to 0.375 nm/mA when the oxide aperture increases from 2.7 μm to 9 μm.The thermal resistance decreases from 2.815℃/mW to 1.015℃/mW when the oxide aperture increases from 4.4 μm to 18.7μm.It is demonstrated theoretically and experimentally that the wavelength spacing between adjacent modes increases with the augment of the injection current and the spacing becomes smaller with the oxide aperture increasing.Thus it can be reported that the aperture size can effectively reduce the mode overlaying but at the cost of the power decreasing and the wavelength tuning rate and thermal resistance increasing.
