Browsing by Author "Chang, YA"

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10 Gbps InGaAs : Sb-G-aAs-GaAsP quantum well vertical cavity surface emitting lasers with 1.27 mu m emission wavelengths
(2005-04-01)
Chang, YH
;
Kuo, HC
;
Chang, YA
;
Chu, JT
;
Tsai, MY
InGaAs:Sb-GaAs-GaAsP vertical cavity surface emitting lasers (VCSELs) with 1.27 mu m emission wavelength were grown by metal-organic chemical vapor deposition (MOCVD) and exhibited excellent performance and temperature stability. The threshold current changes from 1.8 to 1.1 mA and the slope efficiency falls less than similar to 35% as the temperature is increased from room temperature to 70 degrees C. With a bias current of only 5 mA, the 3 dB modulation frequency response was measured to be 8.36GHz, which is appropriate for 10Gb/s operation. The maximal bandwidth is measured to be 10.7GHz With a modulation current efficiency factor (MCEF) of similar to 5.25 GHz/(mA) 1/2. Bit error rates of less than 10(-12) are demonstrated for 10 Gb/s data transmission from 25 degrees C to 70'C. We also accumulated life test data up to 1000 h at 70 degrees C/10 mA.
A novel method to improve VCSELs oxide-confined aperture uniformity using selective As+-implanted underlying layer
(2006-05-10)
Huang, HW
;
Kao, CC
;
Chang, YA
;
Kuo, HC
;
Laih, LH
We report the utilization of an selective As+-implanted underlying layer and regrowth method to enhance and control the wet thermal oxidation rate for 850 nm oxide-confined VCSEL. The oxidation rate of the As'-implanted device showed a four-fold increase over the non-implanted one at the As' dosage of 1 x 10(16) cm(-1) and the oxidation temperature of 400 degrees C. The 50 side-by-side As'-implanted oxide-confined VCSELs fabricated using the method achieved very uniform performance with a deviation in threshold current Of Delta I-th similar to 0.2 mA and slope-efficiency of Delta S.E. similar to 3%. Finally, we accumulated life test data for oxide-confined VCSELs with As'-implanted underlying layer up to 1000 h at 80 degrees C/15 mA. (c) 2005 Elsevier B.V. All rights reserved.
Characteristics of vertical thermal/PECVD polysilicon oxides formed on the sidewall of polysilicon films
(2003-01-01)
Lee, MZ
;
Chang, YA
;
Lee, CL
;
Lei, TF
;
電子工程學系及電子研究所
Vertical thermal and PECVD (plasma enhanced chemical vapor deposition) polysilicon oxides, formed on polysilicon sidewalls, are investigated to demonstrate that the oxides on polysilicon sidewalls have much better electrical qualities than do conventional planar polysilicon oxides. For thermally grown vertical polysilicon oxides, the charges-to-breakdown were as high as 10 C/cm(2), values that are comparable to that of the single crystal oxide. This improvement is primarily due to the fewer number of grain boundaries in the vertical direction of the polysilicon. (C) 2002 The Electrochemical Society.
Fabrication and characteristics of high-speed oxide-confined VCSELs using InGaAsP-InGaP strain-compensated MQWs
(2004-12-01)
Chang, YH
;
Kuo, HC
;
Lai, FI
;
Chang, YA
;
Lu, CY
This paper presents the fabrication and characteristics of high-performance 850-mn InGaAsP-InGaP strain-compensated multiple-quantum-well (MQW) vertical-cavity surface-emitting lasers (VCSELs). The InGaAsP-InGaP MQW's composition was optimized through theoretical calculations, and the growth condition was optimized using photoluminescence. These VCSELs exhibit superior performance with characteristics threshold currents similar to0.4 mA and slope efficiencies similar to0.6 mW/mA. The threshold current change with temperature is less than 0.2 mA, and the slope efficiency drops less than similar to30% when the substrate temperature is raised from room temperature to 85degreesC. A high modulation bandwidth of 14.5 GHz and a modulation current efficiency factor of 11.6 GHz/(mA) (1/2) are demonstrated. The authors have accumulated life test data up to 1000 h at 70degreesC/8 mA.
Fabrication of high speed and reliable 850nm oxide-confined VCSELs for 10Gb/s data communication
(2005)
Kuo, HC
;
Chang, YH
;
Chang, YA
;
Tseng, KF
;
Laih, LH
In this paper, we demonstrate high performance 850 nm InGaAsP/InGaP strain-compensated MQWs vertical-cavity surface-emitting lasers (VCSELs). These VCSELs exhibit superior performance with threshold currents of similar to 0.4 mA, and slope efficiencies of similar to 0.6 mW/mA. High modulation bandwidth of 14.5 GHz and modulation current efficiency factor of 11.6 GHz/(mA)(1/2) are demonstrated. We have accumulated life test data up to 1000 hours at 70 degrees C/8mA. In addition, we also report a high speed planarized 850nm oxide-implanted VCSELs process that does not require semiinsulating substrates, polyimide planarization process, or very small pad areas, therefore very promising in mass manufacture.
High temperature stability 850-nm In0.15Al0.08Ga0.77As/Al0.3Ga0.7As vertical-cavity surface-emitting laser with single Al0.75Ga0.25As current blocking layer
(2005)
Chang, YA
;
Lai, FI
;
Yu, HC
;
Kuo, HC
;
Laih, LW
In this paper, we employed a high bandgap Al0.75Ga0.25As layer acting as an electronic blocking layer in the upper In0.15Al0.08Ga0.77As/Al0.3Ga0.7As active region before the growth of p-type layers of 850-nm vertical-cavity surface-emitting lasers (VCSELs). A threshold current of 1.33mA and slope efficiency of 0.53W/A at 25 degrees C were obtained, and the temperature dependent light output and voltage versus current (L-I-V) characteristics showed that the VCSELs with a high bandgap Al0.75Ga0.25As layer were more stable when the substrate temperature was in a range of 25-95 degrees C. The threshold current increased with temperature up to 95 degrees C was less than 21% and the slope efficiency dropped only 24.5%.
High-speed modulation of InGaAs : Sb-GaAs-GaAsP quantum-well vertical-cavity surface-emitting lasers with 1.27-mu m emission wavelength
(2005-03-01)
Kuo, HC
;
Chang, YH
;
Yao, HH
;
Chang, YA
;
Lai, FI
1.27-mum InGaAs: Sb-GaAs-GaAsP vertical-cavity surface-emitting lasers (VCSELs) were grown by metal-organic chemical vapor deposition and exhibited excellent performance and temperature stability. The threshold current changes from 1.8 to 1.1 mA and the slope efficiency falls less than similar to35% as the temperature raised from room temperature to 70 degreesC. With a bias current of only 5 mA, the 3-dB modulation frequency response was measured to be 8.36 GHz, which is appropriate for 10-Gb/s operation. The maximal bandwidth is measured,to be 10.7 GHz with modulation current efficiency factor (MCEF) of similar to5.25 GHz/(mA)(1/2). These VCSELs also demonstrate high-speed modulation up to 10 Gb/s from 25 degreesC to 70 degreesC.
Improved photoluminescence of 1.26 mu m InGaAs/GaAs quantum wells assisted by Sb surfactant and indium-graded intermediate layers
(2005-08-08)
Chang, YA
;
Kuo, HC
;
Chang, YH
;
Wang, SC
;
光電工程學系
We have grown high-quality InGaAs/GaAs quantum wells (QWs) with emission wavelength range of 1.2-1.26 mu m by metalorganic chemical vapor depositions. By incorporating Sb surfactant and the indium-graded intermediate layers into InGaAs/GaAs QWs, the photoluminescence (PL) intensity of the 1.26-mu m In0.45Ga0.55As/GaAs QW is enhanced by a factor of 20 and the full width at half maximum value is reduced from 60.4 meV to 35.9 meV. The good crystalline quality is proved by temperature-dependent PL, which shows that the activation energies of In0.45Ga0.55As and Sb-assisted indium-graded In0.45Ga0.55As QWs are 20.87 meV and 27.09 meV. (c) 2005 American Institute of Physics.
Improvement of high speed performance for 10-Gb/s 850-nm VCSELs using InGaAsP/InGaP strain-compensated MQWs
(2004)
Chang, YS
;
Kuo, HC
;
Lai, FI
;
Chang, YA
;
Laih, LH
We present in this paper the MOCVD growth and characterization of high performance 850nm InGaAsP/InGaP strain-compensated MQWs vertical-cavity surface-emitting lasers (VCSELs). These VCSELs exhibit superior characteristics, with threshold currents similar to0.4 mA, and slope efficiencies similar to 0.6 mW/mA. The threshold current change is less than 0.2 mA and the slope efficiency drops by less than similar to30% when the substrate temperature is raised from room temperature to 85degreesC. These VCSELs also demonstrate high speed modulation bandwidth up to 12.5Gbit/s from 25degreesC to 85degreesC.
Improving high-temperature performance in continuous-wave mode InGaAsN/GaAsN ridge waveguide lasers
(2005-06-01)
Chang, YA
;
Kuo, HC
;
Lu, CY
;
Kuo, YK
;
Wang, SC
Continuous-wave (CW) mode operation InGaAsN/GaAsN double-quantum-well lasers with a laser wavelength of 1.295 mu m are demonstrated by metal-organic chemical vapour deposition (MOCVD). With the use of a high-bandgap GaAs0.9P0.1 into the active region before the growth of p-type layers, a room temperature (RT) threshold current of 99 mA and the characteristic temperature (TO) values of 155 K in a temperature range of 25-95 degrees C and 179 K in a temperature range of 25-85 degrees C are obtained from a 4 x 1000 mu m(2) ridge waveguide uncoated laser diode. The To value of the conventional structure without the high-bandgap GaAs0.9P0.1 is 118 K in a temperature range of 25-95 degrees C. High-temperature performance is improved and the results of numerical analysis suggest that it may be attributed to the reduced electronic leakage current.
MOCVD growth of highly strained 1.3 mu m InGaAs : Sb/GaAs vertical cavity surface emitting laser
(2006-01-25)
Chang, YA
;
Chu, JT
;
Ko, CT
;
Kuo, HC
;
Lin, CF
In0.45Ga0.55As:Sb/GaAs (1.3 mu m) vertical cavity surface emitting lasers (VCSELs) were grown by metalorganic chemical vapor deposition (MOCVD). A In0.45Ga0.55As:Sb/GaAs quantum well (QW) exhibited an emission wavelength of 1.26 mu m with narrow fullwidth at half-maximum (FWHM) of 35.9meV. For the fabricated VCSEL with 5 mu m diameter oxide-confined aperture, a room-temperature (RT).threshold current of 2.1 mA and an output power of 0.9 mW with 1.3 mu m emission were obtained. The 3 dB modulation frequency was measured to be 7.6 GHz. (c) 2005 Elsevier B.V. All rights reserved.
MOCVD growth of highly strained InGaAs : Sb-GaAs-GaAsP quantum well vertical cavity surface-emitting lasers with 1.27 mu m emission
(2004-12-10)
Kuo, HC
;
Yao, HH
;
Chang, YH
;
Chang, YA
;
Tsai, MY
1.27mum InGaAs:Sb-GaAs-GaAsP vertical cavity surface-emitting lasers (VCSELs) were grown by metalorganic chemical vapor deposition (MOCVD) with superior performance. The threshold current changes between 1.8 and 1.1 mA and the slope efficiency drops below similar to35% when the temperature is raised from room temperature to 70degreesC. With only 5 mA of bias current, the 3 dB modulation frequency response is measured to be 8.36 GHz which is suitable for 10Gb/s operation. The maximal bandwidth is estimated to 10.7GHz with modulation current efficiency factor MCEF) of similar to5.25GHz/(mA)(1/2). The results of InGaAs:Sb-GaAs-GaAsP VCSELs can reach a performance level comparable to GalnAsN VCSELs with better thermal stability and should be considered as a very promising candidate for 1.3 mum commercial applications. (C) 2004 Elsevier B.V. All rights reserved.
Simulation and analysis of 1300-nm In0.4Ga0.6As0.986N0.014/GaAs1-xNx quantum-well lasers with various GaAs1-xNx strain compensated barriers
(2004)
Chang, YA
;
Kuo, HC
;
Chang, YH
;
Wang, SC
;
Laih, LH
In this article, the laser performance of the 1300-nm In0.4Ga0.6As0.986N0.014/GaAs1-xNx quantum well lasers with various GaAs1-xNx strain compensated barriers (x=0%, 0.5%, 1 %, and 2%) have been numerically investigated with a laser technology integrated simulation program. The simulation results suggest that with x=0% and 0.5% can have better optical gain properties and high characteristic temperature coefficient To values of 110 K and 94 K at the temperature range of 300-370 K. As the nitrogen composition in GaAs1-xNx barrier increases more than 1% the laser performance degrades rapidly and the To value decreases to 87 K at temperature range of 300-340 K. This can be attributed to the decrease of conduction band carrier confinement potential between In0.4Ga0.6As0.986N0.014 QW and GaAs1-xNx barrier and the increase of electronic leakage current. Finally, the temperature dependent electronic leakage current in the InGaAsN/GaAs1-xNx quantum-well lasers are also investigated.
Simulation of 1300-nm In(0.4)Ga(0.6)As(0.986)N(0.014)/GaAs(1-x)N(x) quantum-well lasers with various GaAs(1-x)N(x) strain compensated barriers
(2004-11-01)
Chang, YA
;
Kuo, HC
;
Chang, YH
;
Wang, SC
;
光電工程學系
In this article, the laser performance of the 1300-nm In(0.4)Ga(0.6)As(0.986)N(0.014)/GaAs(1 - x)N(x) quantum-well (QW) lasers with various GaAs(1 - x)N(x) strain compensated barriers (x = 0%, 0.5%, 1%, and 2%) has been numerically investigated with a laser technology integrated simulation program. The simulation results suggest that with x = 0% and 0.5% can have better optical gain properties and high characteristic temperature coefficient To values of 110 and 94 K at the temperature range of 300-370 K. As the nitrogen composition in GaAs(1 - x)N(x) barrier increases more than 1% the laser performance degrades rapidly and the To value decreases to 87 K at temperature range of 300-340 K. This can be attributed to the decrease of conduction band carrier confinement potential between In(0.4)Ga(0.6)As(0.986)N(0.014) QW and GaAs(1 - x)N(x) barrier and the increase of electronic leakage current. Finally, the temperature dependent electronic leakage current in the InGaAsN/GaAs(1 - x)N(x) quantum-well lasers are also investigated. (C) 2004 Elsevier B.V. All rights reserved.
Simulation of 1300-nm In0.4Ga0.6As0.986N0.014/GaAs1-xNx quantum-well lasers with various GaAs1-xNx strain compensated barriers
(2004-11-01)
Chang, YA
;
Kuo, HC
;
Chang, YH
;
Wang, SC
;
光電工程學系
In this article, the laser performance of the 1300-nm In0.4Ga0.6As0.986N0.014/GaAs1 - xNx quantum-well (QW) lasers with various GaAs1 - xNx strain compensated barriers (x = 0%, 0.5%, 1%, and 2%) has been numerically investigated with a laser technology integrated simulation program. The simulation results suggest that with x = 0% and 0.5% can have better optical gain properties and high characteristic temperature coefficient To values of 110 and 94 K at the temperature range of 300-370 K. As the nitrogen composition in GaAs1 - xNx barrier increases more than 1% the laser performance degrades rapidly and the To value decreases to 87 K at temperature range of 300-340 K. This can be attributed to the decrease of conduction band carrier confinement potential between In0.4Ga0.6As0.986N0.014 QW and GaAs1 - xNx barrier and the increase of electronic leakage current. Finally, the temperature dependent electronic leakage current in the InGaAsN/GaAs1 - xNx quantum-well lasers are also investigated. (C) 2004 Elsevier B.V. All rights reserved.
Simulation of InGaN quantum well laser performance using quaternary InAlGaN alloy as electronic blocking layer
(2005-11-01)
Chang, YA
;
Luo, CY
;
Ku, HC
;
Kuo, YK
;
Lin, CF
Laser performance of an InGaN edge-emitting laser using a quaternary InAlGaN electronic blocking layer is investigated. Varying the aluminum (Al) composition in InAlGaN with a fixed indium (In) value (Al : In = 5 : 1) indicates that a lower threshold current and higher characteristic temperature (T(0)) value can be obtained when the Al composition is higher than 20%. When Al = 25%, the threshold current is reduced at the expense of a decreased To value from 149 to 130 K when the In composition increases from 1 to 7% in a temperature range of 300-370 K. The decreased T(0) value is mainly attributed to the increase in electronic leakage current.
Single mode 1.27-mu m InGaAS : Sb-GaAs-GaAsP quantum well vertical cavity surface emitting lasers
(2005-01-01)
Kuo, HC
;
Chang, YA
;
Chang, YH
;
Chu, JT
;
Tsai, MY
1.27 mu m InGaAs:Sb-GaAs-GaAsP vertical cavity surface emitting lasers (VCSELs) were grown by metalorganic chemical vapor deposition (MOCVD) and exhibited excellent performance and temperature stability. The threshold current changes from 1.8 to 1.1 mA and the slope efficiency falls less than similar to 35% as the temperature raised from room temperature to 70 degrees C. With a bias current of only 5mA, the 3dB modulation frequency response was measured to be 8.36 GHz, which is appropriate for 10 Gb/s operation. The maximal bandwidth is measured to be 10.7 GHz with modulation current efficiency factor (MCEF) of similar to 5.25 GHz/(mA)(1/2). These VCSELs also demonstrate high-speed modulation up to 10 Gb/s from 25 degrees C to 70 degrees C.
Single-mode 1.27-mu m InGaAs : Sb-GaAs-GaAsP quantum well vertical cavity surface emitting lasers
(2005-01-01)
Kuo, HC
;
Chang, YH
;
Chang, YA
;
Lai, FI
;
Chu, JT
The 1.27-mum InGaAs:Sb-GaAs-GaAsP vertical cavity surface emitting lasers (VCSELs) were grown by metalorganic chemical vapor deposition and exhibited excellent performance and temperature stability. The threshold current varies from 1.8 to 1.1 mA and the slope efficiency falls less than similar to35% from 0.17 to 0.11 mW/mA as the temperature is raised from room temperature to 75 degreesC. The VCSELs continuously operate up to 105 degreesC with a slope efficiency of 0.023 mW/mA. With a bias current of only 5 mA, the 3-dB modulation frequency response was measured to be 8.36 GHz, which is appropriate for 10-Gb/s operation. The maximal bandwidth is estimated to be 10.7 GHz(1/2) with modulation current efficiency factor of similar to5.25 GHz/(mA)(1/2). These VCSELs also demonstrate high-speed modulation up to 10 Gb/s from 25degreesC to 70degreesC. We also accumulated life test data up to 1000 h at 70degreesC/10 mA.
Theoretical and experimental analysis on InAlGaAs/AlGaAs active region of 850-nm vertical-cavity surface-emitting lasers
(2006-01-01)
Chang, YA
;
Chen, JR
;
Kuo, HC
;
Kuo, YK
;
Wang, SC
In this study, the gain-carrier characteristics of In0.02Ga0.98As and InAlGaAs quantum wells (QWs) of variant In and Al compositions with an emission wavelength of 838 nm are theoretically investigated. More compressive strain, caused by higher In and Al compositions in InAlGaAs QW, is found to provide higher material gain, lower transparency carrier concentration, and transparency radiative current density over the temperature range of 25-95 degrees C. To improve the output characteristics and high-temperature performance of 850-nm verticalcavity surface-emitting laser (VCSEL), In(0.15)AI(0.08)Ga(0.77)As/ Al0.3Ga0.7As is utilized as the active region, and a high-bandgap 10-nm-thick Al-0.75 Ga0.25As electronic blocking layer is employed for the first time. The threshold current and slope efficiency of the VCSEL with A(10.7)SGa(0.25)As at 25 degrees C are 1.33 mA and 0.53 W/A, respectively. When this VCSEL is operated at an elevated temperature of 95 C, the increase in threshold current is less than 21 % and the decrease in slope efficiency is approximately 24.5%. A modulation bandwidth of 9.2 GHz biased at 4 mA is demonstrated.