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D Bimberg - One of the best experts on this subject based on the ideXlab platform.
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25 gbps direct Modulation and 10 km data transmission with 1310 nm waveband wafer fused vcsels
Optics Express, 2016Co-Authors: A Caliman, D Bimberg, A Mereuta, P Wolf, Alexei Sirbu, V Iakovlev, E KaponAbstract:Direct Modulation at >25 Gbps is achieved with 1310 nm wavelength wafer fused VCSELs by adjusting the strain in the quantum well active region and the cavity photon lifetime. 25 + Gbps large Signal Modulation with 10-12 BER at 1310 nm across 10 km of standard single mode fiber is demonstrated.
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impact of photon lifetime on the temperature stability of 50 gb s 980 nm vcsels
IEEE Photonics Technology Letters, 2016Co-Authors: Gunter Larisch, James A. Lott, Philip Moser, D BimbergAbstract:An increase of the small-Signal Modulation bandwidth to more than 25 GHz that is stable over a wide temperature range from 25 °C to 85 °C is reported upon systematic, joint variations of the photon lifetime and the oxide-aperture diameter for 980-nm vertical-cavity surface-emitting lasers. Error-free back-to-back data transmission at 50 Gb/s from 25 °C to 75 °C for completely unchanged driving conditions is reported, leading to an improved energy efficiency of the laser.
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error free transmission over 1 km om4 multimode fiber at 25 gb s using a single mode photonic crystal vertical cavity surface emitting laser
IEEE Photonics Technology Letters, 2013Co-Authors: Stewart T. M. Fryslie, N N Ledentsov, D Bimberg, James A. Lott, Kent D. ChoquetteAbstract:With the separation of optical and current apertures, photonic crystal vertical-cavity surface-emitting lasers can reach a 3-dB small-Signal Modulation bandwidth of > 18 GHz while lasing in the fundamental mode. Because of reduced chromatic dispersion, such devices enable error-free transmission over 1-km OM4 multimode fiber at a data rate of 25 Gb/s and operating at a current density of 5.4 kA/cm2. This can potentially lead to a laser source that is useful for rack-to-rack transmissions in large data centers and potentially long device lifetime.
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on the relationship between small and large Signal Modulation capabilities in highly nonlinear quantum dot lasers
Applied Physics Letters, 2013Co-Authors: D Gready, Ivo Montrosset, G Eisenstein, Mariangela Gioannini, D Arsenijevic, H Schmeckebier, M Stubenrauch, D BimbergAbstract:The small Signal Modulation response of semiconductor lasers is commonly used to predict large Signal Modulation capabilities. Recent experiments suggest that this prediction may fail in some quantum dot (QD) lasers. We present a model supported by experiments, which shows that when the small Signal Modulation response is limited by gain compression and the gain is large, the laser can be modulated at very high bit rates. This effect is inherent to dynamics governing all semiconductor lasers but the conditions needed for high bit rate Modulation in the presence of narrow small Signal bandwidths are only obtainable in QD lasers.
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Modulation characteristics of high speed and high temperature stable 980 nm range vcsels operating error free at 25 gbit s up to 85 c
IEEE Journal of Selected Topics in Quantum Electronics, 2011Co-Authors: A Mutig, S A Blokhin, A M Nadtochiy, J A Lott, Philip Moser, P Wolf, Werner Hofmann, D BimbergAbstract:High-speed oxide-confined 980 nm vertical cavity surface emitting lasers (VCSELs), exhibiting very temperature stable static and dynamic characteristics, are presented, which are well-suited for future optical data link and high-performance computing applications. Error-free operation at data rates of 25 Gbit/s in a wide temperature range from 25 to 85 °C is achieved without the need to adjust any of the electrical driving parameters. Small-Signal Modulation of VCSELs with different oxide aperture diameters is analyzed to identify the primary mechanisms that control device Modulation rate by extracting the standard two-pole rate equation parameters.
James A. Lott - One of the best experts on this subject based on the ideXlab platform.
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bandwidth and optical output power of vcsels and vcsel arrays
Vertical-Cavity Surface-Emitting Lasers XXIII, 2019Co-Authors: Nasibeh Haghighi, Philip Moser, James A. LottAbstract:Via single 980 nm VCSELs with oxide aperture diameters (ϕ) of about 3 to 16 μm and via electrically-parallel triple and septuple two-dimensional arrays of optically-uncoupled 980 nm VCSELs with ϕ of about 3.5 μm we achieve small Signal Modulation bandwidths of 20-30 GHz and operating optical output powers of about 5 to 50 mW.
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Power, Bandwidth, and Efficiency of Single VCSELs and Small VCSEL Arrays
IEEE Journal of Selected Topics in Quantum Electronics, 2019Co-Authors: Nasibeh Haghighi, Philip Moser, James A. LottAbstract:Single-emitter vertical-cavity surface-emitting lasers (VCSELs) and multiple-emitter VCSEL arrays designed for emission at 980 nm, and with large oxide aperture diameters ( φ ) from ∼10.5 to 33.5 μm and with φ of ∼7.5 μm that are configured in three-emitter and seven-emitter electrically parallel triangular and hexagonal arrays, respectively, have record bandwidths and optical output powers for VCSELs with such large cumulative emitting areas. We demonstrate room temperature (RT) maximum small-Signal Modulation bandwidths ( f 3dBmax) of 26.6 to 18.6 GHz with corresponding continuous wave (CW) optical output powers ( L ) of 16.2 and 47 mW for VCSELs with φ ∼13.5 and 33.5 μm, respectively. For parallel 980 nm triple and septuple arrays with φ ∼7.5 μm for each VCSEL, we demonstrate RT f 3dBmax of 25.5 and 24.8 GHz with corresponding CW L of 22.7 and 50.1 mW, respectively. We perform a comparative analysis of the RT results, which consist of standard static light output power–current–voltage ( LIV ) characteristics to determine the typical VCSEL figures-of-merit including wall plug efficiency (WPE), LI slope efficiency, spectral emission versus current ( I ), and small-Signal frequency response curves. We examine the tradeoffs in optical output power, small-Signal Modulation bandwidth, and WPE for the various VCSEL designs, and find that while the combination of f 3dBmax and L are record values for single VCSELs and VCSEL arrays, these parameters fall off as the cumulative VCSEL array area increases to emit higher overall optical power.
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23 ghz bandwidth and 25 mw peak optical output power with 980 nm oxide aperture vcsels
IEEE Photonics Conference, 2018Co-Authors: Nasibeh Haghighi, R Rosales, Gunter Larisch, James A. LottAbstract:Conventional vertical-single-cavity surface-emitting lasers with oxide aperture diameters (φ) of ∼16 μm exhibit record room temperature small-Signal Modulation bandwidths (f3dB) of 23 GHz in concert with optical output powers of 25 mW. The same wafer yields f3dB exceeding 30 GHz when φ ∼2.5–4.0 μm.
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35 ghz bandwidth with directly current modulated 980 nm oxide aperture single cavity vcsels
International Semiconductor Laser Conference, 2018Co-Authors: Nasibeh Haghighi, R Rosales, Gunter Larisch, Martin Zorn, James A. LottAbstract:Vertical-single-cavity surface-emitting lasers emitting in a quasi-single mode at 980 nm and based on a simplified epitaxial design with oxide aperture diameters of about 3 μm and an output coupling mirror power reflectance below 0.99 exhibit record room temperature small-Signal Modulation bandwidths of 35 GHz.
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29 ghz small Signal Modulation bandwidth for directly current modulated 980 nm oxide aperture vcsels
IEEE Optical Interconnects Conference, 2017Co-Authors: R Rosales, Philip Moser, James A. LottAbstract:An epitaxial design with a half-lambda optical cavity surrounded by only two oxide-current apertures as small as 2-micrometer in diameter leads to highly confined optical fields and carriers and to a record 29.3-GHz small-Signal Modulation bandwidth at room temperature for 980-nm vertical-cavity surface-emitting lasers.
P Bhattacharya - One of the best experts on this subject based on the ideXlab platform.
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temperature dependent measurement of auger recombination in in0 40ga0 60n gan red emitting λ 630 nm quantum dots
Applied Physics Letters, 2014Co-Authors: Thomas Frost, Animesh Banerjee, Shafat Jahangir, P BhattacharyaAbstract:We have derived the Auger recombination coefficients, as a function of temperature, for In0.4Ga0.6N/GaN self-organized quantum dots from large-Signal Modulation measurements made on lasers in which the quantum dots form the gain media. The value of Ca = 1.3 ±0.2 × 10−31 cm6 s−1 at room temperature and the coefficient decreases with increase of temperature.
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carrier dynamics and high speed Modulation properties of tunnel injection ingaas gaas quantum dot lasers
IEEE Journal of Quantum Electronics, 2003Co-Authors: P Bhattacharya, J. Singh, S Ghosh, S Pradhan, Zongkwei Wu, J Urayama, Theodore B NorrisAbstract:We have performed pump-probe differential transmission spectroscopy (DTS) measurements on In/sub 0.4/Ga/sub 0.6/As-GaAs-AlGaAs heterostructures, which show that at room temperature, injected electrons preferentially occupy the excited states in the dots and states in the barriers layers. The relaxation time of these carriers to the dot ground state is >100 ps. This leads to large gain compression in quantum-dot (QD) lasers and limits the attainable small-Signal Modulation bandwidth to /spl sim/ 5-7 GHz. The problem can be alleviated by tunneling "cold" electrons into the lasing states of the dots from an adjoining injector layer. The design, growth, and steady-state and small-Signal Modulation characteristics of tunnel injection In/sub 0.4/Ga/sub 0.6/As-GaAs QD lasers are described and discussed. The tunneling times, directly measured by three-pulse DTS measurements, are /spl sim/ 1.7 ps and independent of temperature. The measured small-Signal Modulation bandwidth for I/I/sub th/ /spl sim/ 7 is f/sub -3 dB/ = 23 GHz and the gain compression factor for this frequency response is /spl epsiv/ = 8.2 /spl times/ 10/sup -16/ cm/sup 3/. The differential gain obtained from the Modulation data is dg/dn /spl cong/ 2.7 /spl times/ 10/sup -14/ cm/sup 2/ at room temperature. The value of the K-factor is 0.205 ns and the maximum intrinsic Modulation bandwidth is 43.3 GHz. Analysis of the transient characteristics with appropriate carrier and photon rate equations yield Modulation response characteristics identical to the measured ones. The Auger coefficients are in the range /spl sim/ 3.3 /spl times/ 10/sup -29/ cm/sup 6//s to 3.8 /spl times/ 10/sup -29/ cm/sup 6//s in the temperature range 15/spl deg/C
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dynamic characteristics of high speed in0 4ga0 6as gaas self organized quantum dot lasers at room temperature
Applied Physics Letters, 2002Co-Authors: S Ghosh, S Pradhan, P BhattacharyaAbstract:We have measured the room-temperature Modulation characteristics of self-organized In0.4Ga0.6As/GaAs quantum dot lasers in which electrons are injected into the dot lasing states by tunneling. A small-Signal Modulation bandwidth of f−3 dB=22 GHz is measured. Values of differential gain at 288 K of dg/dn≅8.85×10−14 cm2 and gain compression factor e=7.2×10−16 cm3 are derived from the Modulation data. Extremely low values of linewidth enhancement factor α∼1 and chirp <0.6 A were also measured in the devices.
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tunnel injection in0 4ga0 6as gaas quantum dot lasers with 15 ghz Modulation bandwidth at room temperature
Applied Physics Letters, 2002Co-Authors: P Bhattacharya, S GhoshAbstract:By utilizing tunnel injection of electrons, first demonstrated in quantum well lasers, we have measured enhanced small-Signal Modulation bandwidth, f−3dB, and reduced temperature sensitivity of the threshold current, characterized by T0, in In0.4Ga0.6As/GaAs self-organized quantum dot ridge waveguide lasers. Values of f−3dB=15 GHz at 283 K and T0=237 K for 318⩾T⩾278 are measured in these devices. The differential gain at 283 K is dg/dn≅8.5×10−14 cm2 and the gain compression factor e=4.5×10−17 cm3.
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small Signal Modulation characteristics of self organized quantum dot separate confinement heterostructure and tunneling injection lasers
Lasers and Electro-Optics Society Meeting, 1997Co-Authors: K Kamath, David Klotzkin, P BhattacharyaAbstract:We have characterized the dynamic properties of single- and multi-dot layer (to enhance the confinement factor) single mode self-assembled InGaAs-GaAs quantum dot lasers at room temperature. In particular, we have investigated tunneling injection of electrons in quantum dot lasers, as a means to overcome the carrier relaxation bottleneck, for the first time.
Pallab Bhattacharya - One of the best experts on this subject based on the ideXlab platform.
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small Signal Modulation and differential gain of red emitting λ 630 nm ingan gan quantum dot lasers
Applied Physics Letters, 2013Co-Authors: Thomas Frost, Animesh Banerjee, Pallab BhattacharyaAbstract:We report small-Signal Modulation bandwidth and differential gain measurements of a ridge waveguide In0.4Ga0.6N/GaN quantum dot laser grown by molecular beam epitaxy. The laser peak emission is at λ = 630 nm. The −3 dB bandwidth of an 800 μm long device was measured to be 2.4 GHz at 250 mA under pulsed biasing, demonstrating the possibility of high-speed operation of these devices. The differential gain was measured to be 5.3 × 10−17 cm2, and a gain compression factor of 2.87 × 10−17 cm3 is also derived from the small-Signal Modulation response.
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characteristics of a high speed 1 22 μm tunnel injection p doped quantum dot excited state laser
Applied Physics Letters, 2011Co-Authors: Pallab Bhattacharya, Thomas FrostAbstract:The measured characteristics of excited state lasing in tunnel injection p-doped InAs quantum dot lasers are reported. Excited state lasing at 1.22 μm is ensured by a high-reflectivity facet coating which is designed to suppress ground state lasing in the devices. The saturation modal gain in the excited states is 56 cm−1, which is a factor of ∼2.5 higher than that of the ground state. The small-Signal Modulation bandwidth for I=4.5Ith is 13.5 GHz and the differential gain is 1.1×10−15 cm2.
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small Signal Modulation and differential gain of single mode self organized in0 4ga0 6as gaas quantum dot lasers
Applied Physics Letters, 1997Co-Authors: K Kamath, J. Singh, J D Phillips, Hongtao Jiang, Pallab BhattacharyaAbstract:We report small-Signal Modulation bandwidth and differential gain measurements of a single-layer self-organized In0.4Ga0.6As/GaAs quantum dot laser grown by molecular beam epitaxy. The 3 dB bandwidth of single-mode ridge waveguide lasers was measured to be 7.5 GHz at 100 mA under pulsed measurements, demonstrating the possibility of high speed operation of these devices. The differential gain was measured to be 1.7×10−14 cm2.
Philip Moser - One of the best experts on this subject based on the ideXlab platform.
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bandwidth and optical output power of vcsels and vcsel arrays
Vertical-Cavity Surface-Emitting Lasers XXIII, 2019Co-Authors: Nasibeh Haghighi, Philip Moser, James A. LottAbstract:Via single 980 nm VCSELs with oxide aperture diameters (ϕ) of about 3 to 16 μm and via electrically-parallel triple and septuple two-dimensional arrays of optically-uncoupled 980 nm VCSELs with ϕ of about 3.5 μm we achieve small Signal Modulation bandwidths of 20-30 GHz and operating optical output powers of about 5 to 50 mW.
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Power, Bandwidth, and Efficiency of Single VCSELs and Small VCSEL Arrays
IEEE Journal of Selected Topics in Quantum Electronics, 2019Co-Authors: Nasibeh Haghighi, Philip Moser, James A. LottAbstract:Single-emitter vertical-cavity surface-emitting lasers (VCSELs) and multiple-emitter VCSEL arrays designed for emission at 980 nm, and with large oxide aperture diameters ( φ ) from ∼10.5 to 33.5 μm and with φ of ∼7.5 μm that are configured in three-emitter and seven-emitter electrically parallel triangular and hexagonal arrays, respectively, have record bandwidths and optical output powers for VCSELs with such large cumulative emitting areas. We demonstrate room temperature (RT) maximum small-Signal Modulation bandwidths ( f 3dBmax) of 26.6 to 18.6 GHz with corresponding continuous wave (CW) optical output powers ( L ) of 16.2 and 47 mW for VCSELs with φ ∼13.5 and 33.5 μm, respectively. For parallel 980 nm triple and septuple arrays with φ ∼7.5 μm for each VCSEL, we demonstrate RT f 3dBmax of 25.5 and 24.8 GHz with corresponding CW L of 22.7 and 50.1 mW, respectively. We perform a comparative analysis of the RT results, which consist of standard static light output power–current–voltage ( LIV ) characteristics to determine the typical VCSEL figures-of-merit including wall plug efficiency (WPE), LI slope efficiency, spectral emission versus current ( I ), and small-Signal frequency response curves. We examine the tradeoffs in optical output power, small-Signal Modulation bandwidth, and WPE for the various VCSEL designs, and find that while the combination of f 3dBmax and L are record values for single VCSELs and VCSEL arrays, these parameters fall off as the cumulative VCSEL array area increases to emit higher overall optical power.
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29 ghz small Signal Modulation bandwidth for directly current modulated 980 nm oxide aperture vcsels
IEEE Optical Interconnects Conference, 2017Co-Authors: R Rosales, Philip Moser, James A. LottAbstract:An epitaxial design with a half-lambda optical cavity surrounded by only two oxide-current apertures as small as 2-micrometer in diameter leads to highly confined optical fields and carriers and to a record 29.3-GHz small-Signal Modulation bandwidth at room temperature for 980-nm vertical-cavity surface-emitting lasers.
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impact of photon lifetime on the temperature stability of 50 gb s 980 nm vcsels
IEEE Photonics Technology Letters, 2016Co-Authors: Gunter Larisch, James A. Lott, Philip Moser, D BimbergAbstract:An increase of the small-Signal Modulation bandwidth to more than 25 GHz that is stable over a wide temperature range from 25 °C to 85 °C is reported upon systematic, joint variations of the photon lifetime and the oxide-aperture diameter for 980-nm vertical-cavity surface-emitting lasers. Error-free back-to-back data transmission at 50 Gb/s from 25 °C to 75 °C for completely unchanged driving conditions is reported, leading to an improved energy efficiency of the laser.
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Modulation characteristics of high speed and high temperature stable 980 nm range vcsels operating error free at 25 gbit s up to 85 c
IEEE Journal of Selected Topics in Quantum Electronics, 2011Co-Authors: A Mutig, S A Blokhin, A M Nadtochiy, J A Lott, Philip Moser, P Wolf, Werner Hofmann, D BimbergAbstract:High-speed oxide-confined 980 nm vertical cavity surface emitting lasers (VCSELs), exhibiting very temperature stable static and dynamic characteristics, are presented, which are well-suited for future optical data link and high-performance computing applications. Error-free operation at data rates of 25 Gbit/s in a wide temperature range from 25 to 85 °C is achieved without the need to adjust any of the electrical driving parameters. Small-Signal Modulation of VCSELs with different oxide aperture diameters is analyzed to identify the primary mechanisms that control device Modulation rate by extracting the standard two-pole rate equation parameters.
