The processing technology of 1.3&mgr;m InAs-InGaAs quantum-dot VCSELs with fully doped DBRs grown by MBE will be
demonstrated. The threshold currents of the fabricated devices with 10 &mgr;m oxide-confined aperture are 0.7mA, which
correspond to 890A/cm2 threshold current density. And the threshold voltage of the device is 1.03V and maximum
output power is 33 &mgr;W. The series resistance is 85 &OHgr; which is 10 times lower then our preliminary work and 3 times
lower then intracavity contacted InAs-InGaAs quantum-dot VCSEL. This relatively lower resistance can even comparable with the best result reported in InGaAs oxide-confined VCSELs with intracavity contact.
1.27 μm 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 ~35% as the temperature raised from room temperature to 70oC. 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 ~ 5.25 GHz/(mA)1/2. These VCSELs also demonstrate high-speed modulation up to 10 Gb/s from 25°C to 70°C.
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 ~0.4 mA, and slope efficiencies of ~ 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°C/8mA. In addition, we also report a high speed planarized 850nm oxide-implanted VCSELs process that does not require semi-insulating substrates, polyimide planarization process, or very small pad areas, therefore very promising in mass manufacture.
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 T0 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 T0 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.
Proton implanted VCSEL has been demonstrated with good reliability and decent modulation speed up to 1.25 Gb/s.
However, kinks in current vs light output (L-I) has been always an issue in the gain-guided proton implant VCSEL.
The kink related jitter and noise performance made it difficult to meet 2.5 Gb/s (OC-48) requirement. The kinks in
L-I curve can be attributed to non-uniform carrier distribution induced non-uniform gain distribution within emission
area. In this paper, the effects of a Ti/ITO transparent over-coating on the proton-implanted AlGaAs/GaAs VCSELs
(15um diameter aperture) are investigated. The kinks distribution in L-I characteristics from a 2 inch wafer is greatly
improved compared to conventional process. These VCSELs exhibit nearly kink-free L-I output performance with
threshold currents ~3 mA, and the slope efficiencies ~ 0.25 W/A. The near-field emission patterns suggest the
Ti/ITO over-coating facilitates the current spreading and uniform carrier distribution of the top VCSEL contact thus
enhancing the laser performance. Finally, we performed high speed modulation measurement. The eye diagram of
proton-implanted VCSELs with Ti/ITO transparent over-coating operating at 2.125 Gb/s with 10mA bias and 9dB
extinction ratio shows very clean eye with jitter less than 35 ps.
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 ~0.4 mA, and slope efficiencies ~ 0.6 mW/mA. The threshold current change
is less than 0.2 mA and the slope efficiency drops by less than ~30% when the substrate temperature is raised from
room temperature to 85°C. These VCSELs also demonstrate high speed modulation bandwidth up to 12.5Gbit/s from
25°C to 85°C.
The near-field emission profiles of oxide confined GaAs vertical cavity surface emitting lasers (VCSELs) with 20 m aperture have been investigated at different operating temperature and different driving current. The subthreshold emission profile provided the information of carrier distributions. At 20oC, a uniform plateau profile was observed at subthreshold emission, which then transferred to a fundamental mode at just above the threshold current. At higher driving current, the fundamental mode evolved into higher order modes due to the spatial hole burning effect. However, at 90oC the subthreshold emission was no longer a uniform plateau profile but showed some locally high gain regions off the aperture center. The subsequent lasing mode profiles showed high order mode in coincidence with these locally high gain regions at 90oC. The higher order mode profiles remained nearly unchanged under different temperature conditions when driving at constant current above the threshold. These locally high gain regions probably caused by the non-uniformity of the open aperture and the current crowding effect. In addition to the spatial hole burning and thermal lensing effect, these locally high gain regions appeared at elevated operation temperature also affected the higher order mode transitions of oxide confined VCSELs.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.