Browsing by Author "Sung, CP"

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1.3-mu m InAs-InGaAs quantum-dot vertical-cavity surface-emitting laser with fully doped DBRs grown by MBE
(2006-01-01)
Yu, HC
;
Wang, JS
;
Su, YK
;
Chang, SJ
;
Lai, FI
We report InAs-InGaAs quantum-dot vertical-cavity surface-emitting lasers (VCSELs) grown by molecular beam epitaxy with fully doped n- and p-doped AlGaAs distributed Bragg reflectors and including an AlAs layer to form a current and waveguiding aperture. The metal contacts are deposited on a topmost p(+) (GaAs)-Ga-. contact layer and on the bottom surface of the n(+)-GaAs substrate. This conventional selectively oxidized top-emitting device configuration avoids the added complexity of fabricating intracavity or coplanar ohmic contacts. The VCSELs operate continuous-wave at room temperature with peak output powers of 0.33 mW and differential slope efficiencies up to 0.23 W/A. The peak lasing wavelengths are near 1.275 mu m, with a sidemode suppression ratio of 28 dB.
Control the transverse mode of vertical cavity surface emitting lasers by anti-reflection coating
(2001)
Chiou, SW
;
Lee, CP
;
Yang, HP
;
Sung, CP
;
電子工程學系及電子研究所
We have successfully developed a selective surface coating technique to control the modal behavior of the ion-implanted vertical cavity surface emitting laser. Using selective deposition of germanium coating by lift-off process, we could spatially control the threshold gain condition of the VCSEL to support the single transverse mode. The threshold current is 7 mA and single transverse mode operation is maintained up to 1 mW. The method is simple and nondestructive compared to other techniques.
Effect of annealing on low-threshold-current large-wavelength InGaAs quantum well vertical-cavity laser
(2006-02-01)
Chen, IL
;
Hsu, WC
;
Kuo, HC
;
Sung, CP
;
Chiou, CH
An emission wavelength record emission wavelength of 1245 nm in double InGaAs/GaAs quantum wells without a strain-compensated barrier is obtained by metalorganic chemical vapor deposition (MOCVD). The effect of annealing on highly strained InGaAs quantum wells is analyzed using phtoluminanescence spectra. By comparing devices p-type distributed Bragg reflector (p-DBR) growth temperatures, the preliminary results indicate that a device with a low p-DBR growth temperature of 670 degrees C exhibits a low threshold current and a high light output power. A threshold current of 6.7 mA in an InGaAs vertical-cavity surface emitting laser (VCSEL) in CW operation is realized with an emission spectrum up to 1.26 mu m.
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 speed (> 13 GHz) modulation of 850 nm vertical cavity surface emitting lasers (VCSELs) with tapered oxide confined layer
(2005-06-01)
Chang, YH
;
Kuo, HC
;
Lai, FI
;
Tzeng, KF
;
Yu, HC
Improved oxide-implanted VCSELs utilising the tapered oxide layer are presented. The VCSELs exhibited similar static performance, but superior modulation bandwidth up to 13.2 GHz, compared with conventional blunt oxide VCSELs. The damping rate was reduced two times in the tapered oxide VCSEL and therefore enhanced the maximal modulation bandwidth. A very clean eye was demonstrated from the improved VCSEL with a rising time of 26 ps, falling time of 40 ps and jitter of less than 20 ps, operating at 10 Gbit/s with 6 mA bias and 6 dB extinction ratio. A comprehensive small signal measurement and analysis was conducted. Based on the equivalent circuit model, the extrinsic bandwidth limitation of the tapered oxide VCSELs was determined.
High-speed (> 10 Gbps) 850 nm oxide-confined vertical cavity surface emitting lasers (VCSELs) with a planar process and reduced parasitic capacitance
(2004-07-01)
Chang, YH
;
Lai, FI
;
Lu, CY
;
Kuo, HC
;
Yu, HC
This study reports the high-speed performance of 850 nm oxide-confined vertical cavity surface emitting lasers (VCSELs) with a planar process and reduced parasitic capacitance. The parasitic capacitance of VCSELs was reduced using additional proton implantation. The small signal modulation bandwidth which was restricted by electric parasitic capacitance expanded from 2.3 GHz to 9 GHz after proton implantation. The reflection coefficient showed that the electric parasitic pole exceeded 20 GHz. An eye diagram of VCSEL with reduced parasitic capacitance operating at 10 Gps with 6 mA bias and 6 dB extinction ratio showed a very clean eye with a jitter of less than 20 ps.
Improvement of high-speed oxide-confined vertical-cavity surface-emitting lasers
(2004-04-01)
Yu, HC
;
Chang, SJ
;
Su, YK
;
Sung, CP
;
Yang, HP
High-speed vertical-cavity surface-emitting lasers that could be modulated up to 10 Giga-bit-per-second (Gbps) were accomplished by using additional proton implantation to reduce the parasitic capacitance. The eye diagram of the implanted device shows a noticeable improvement when compared with those devices without implantation. In contrast to previous reports, moreover, the output power-current-voltage (L-I-V) characteristics of the fabricated devices ill this study show excellent consistency between before and after implantation. The high-temperature lifetime of devices fabricated with a similar process has already exceeded 8100 h up to the present day.
Low-threshold-current-density, long-wavelength, highly strained InGaAs laser grown by metalorganic chemical vapor deposition
(2005-10-01)
Chen, IL
;
Hsu, WC
;
Kuo, HC
;
Yu, HC
;
Sung, CP
A long-emission-wavelength laser with multiple InGaAs/GaAs quantum wells without a strain-compensated barrier was grown by metalorganic chemical vapor deposition (MOCVD). InGaAs quantum well (QW) broad-area laser diodes with an emission wavelength of up to 1214 nm were realized. A measured room-temperature threshold current density of only 173 A/cm(2) for a 2-mm-cavity device and a transparency current density of 66 A/cm(2) were obtained. The internal quantum efficiency and laser cavity loss were 67% and 6 cm(-1), respectively.
Mode control of vertical-cavity surface-emitting lasers by germanium coating
(2001-02-01)
Chiou, SW
;
Lin, G
;
Lee, CP
;
Yang, HP
;
Sung, CP
We have successfully developed a selective surface coating technique to control the modal behavior of the ion-implanted vertical-cavity surface-emitting laser (VCSEL). With selective deposition of a germanium coating by the lift-off process, we could spatially control the threshold gain condition of the VCSEL to support the single transverse mode. The threshold current is 7 mA and single transverse mode operation is maintained up to I mW. The method is simple and nondestructive compared with other techniques.
Singlemode (SMSR > 40 dB) proton-implanted photonic crystal vertical-cavity surface-emitting lasers
(2005-03-17)
Yang, HPD
;
Lai, FI
;
Chang, YH
;
Yu, HC
;
Sung, CP
A proton-implanted photonic crystal vertical-cavity surface-emitting laser for fibre optic applications is demonstrated. Ultra-low threshold current of about 1.25 mA, single fundamental mode (SMSR > 40 dB) CW output power of over 1 mW, with a pulsed output power exceeding 2 mW has been achieved in the 850 nm range.