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ABSTRACT: We studied experimentally and theoretically the substrate-orientation impact on carrier transport and capture in InGaN multiple quantum well (MQW) laser diodes (LDs) with emission in the aquamarine-green spectral range. A new simulation approach was developed to analyze this behavior of LEDs and LDs emitting at these wavelengths. We show that due to deep carrier confinement, the thermal escape from a QW in such devices is negligible. The carrier distribution among QWs is therefore determined by the carrier transport and capture rates. We also show that the ballistic transport mechanism is dominant in this type of MQW active region. In c-plane structures, this mechanism is tunneling-assisted, and therefore, the transport is much slower than in nonpolar and semipolar structures. Because of this, a strong carrier injection nonuniformity observed in c-plane LDs, causes the threshold current increase when number of QWs is >;2. This effect is not observed in semipolar LDs because the carrier transport rate is faster than the capture rate.
IEEE Journal of Selected Topics in Quantum Electronics 11/2011; · 3.78 Impact Factor
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ABSTRACT: Semiconductor pump lasers are an important component in erbium-doped fiber amplifiers and Raman amplifiers. Thermal management has become one of the major obstacles of pump laser development. Understanding of the thermal behavior of high-power laser packages is crucial to the thermal design and optimization of pump lasers. In this paper, we report on the thermal characteristics of a high-power pump laser and discuss the issues associated with heat dissipation. The thermal management of high-power pump laser modules mainly consists of three aspects. One is the thermal resistance reduction which reduces bulk temperature rise in the laser diode chip. The second is facet temperature control, and the third is the thermoelectric cooler (TEC) coefficient of performance improvement. In this paper, the approaches to reduce thermal resistance and facet temperature at the chip level and package level will be reviewed, and the thermal design and optimization of the package assembly to improve the TEC coefficient of performance will be discussed. The thermal resistance of a pump laser could be reduced up to 40% by the proper design of the laser chip and epi-down bonding. An unpumped window design in the pump laser diode is proven to be very effective in reducing the facet temperature and increasing the catastrophic optical mirror damage level. Assembly and package optimization can provide more uniform temperature distribution on TEC cold plate which is critical in improving the TEC coefficient of performance
IEEE Transactions on Components and Packaging Technologies 07/2006; · 0.94 Impact Factor
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Hong Ky Nguyen,
M.H. Hu,
N. Nishiyama,
N.J. Visovsky,
Yabo Li,
Kechang Song,
Xingsheng Liu,
J. Gollier,
Jr. L.C. Hughes, R. Bhat,
Chung-En Zah
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ABSTRACT: We have generated 107-mW green-light emission by frequency doubling of a reliable 1060-nm distributed feedback (DFB) laser diode using a periodically poled MgO-doped lithium niobate waveguide in the most compact single-pass configuration. The green power variation is lower than 1% at frequencies below 82 kHz. The relative intensity noise of -150 dB/Hz has been measured at 100 MHz. We also report 5000-h life-test results of 1060-nm DFB lasers at 80°C.
IEEE Photonics Technology Letters 02/2006; · 2.19 Impact Factor
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M.H. Hu,
Hong Ky Nguyen,
Kechang Song,
Yabo Li,
N.J. Visovsky,
Xingsheng Liu,
N. Nishiyama,
S. Coleman,
L.C. Hughes,
J. Gollier,
W. Miller, R. Bhat,
Chung-En Zah
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ABSTRACT: We report on the static and dynamic performance of high-power and high-modulation-speed 1060-nm distributed Bragg reflector (DBR) lasers for green-light emission by second-harmonic generation. Single-wavelength power of 387 mW at 1060-nm wavelength and green power as high as 99.5 mW were achieved. A thermally induced wavelength tuning of 2.4 nm and a carrier-induced wavelength tuning of -0.85 nm were obtained by injecting current into the DBR section. Measured rise-fall times of 0.2 ns for direct intensity modulation and 0.6 ns for wavelength modulation make the lasers suitable for >50-MHz green-light modulation applications
IEEE Photonics Technology Letters 02/2006; · 2.19 Impact Factor
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Kechang Song,
Yabo Li,
N. Visovsky,
M. Hu,
Hong Ky Nguyen,
Xingsheng Liu,
S. Coleman,
B. Paddock,
M. Turner,
C. Catherine, R. Bhat,
Chung-En Zah
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ABSTRACT: We report a single-wavelength 1060 nm distributed Bragg reflector laser with a record high single lateral mode optical power of 400 mW. These lasers are fabricated using a quantum well intermixing technique for the non-absorbing phase and DBR sections.
Lasers and Electro-Optics Society, 2005. LEOS 2005. The 18th Annual Meeting of the IEEE; 11/2005
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ABSTRACT: 1.3- and 1.55- $mu$ m vertical-cavity surface-emitting lasers (VCSELs) on InP have been realized. High-reflectivity AlGaInAs–InP lattice matched distributed Bragg reflectors (DBRs) were grown on InP substrates. 1.7 (for 1.3 $mu$ m) and 2.0 (for 1.55 $mu$ m) mW single mode power at 25 $^circ$ C, 0.6 mW single mode power at 85 $^circ$ C and lasing operation at $≫hbox100^circ$ C have been achieved. 10 Gbit/s error free transmissions through 10 km standard single mode fiber for 1.3- $mu$ m VCSELs, and through 15 km nonzero dispersion shift fiber for 1.55- $mu$ m VCSELs, have been demonstrated. With the addition of an SOA, 100 km error free transmission at 10 Gbit/s also has been demonstrated through a negative dispersion fiber. No degradation has been observed after over 2500-h aging test.
IEEE Journal of Selected Topics in Quantum Electronics 10/2005; · 3.78 Impact Factor
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ABSTRACT: 1.3-μm InP-based VCSELs with high optical reflection resistance for optical isolator-free 10-Gbps operation have been demonstrated. The 13-GHz relaxation frequency increased the critical feedback level of those VCSELs and allowed 10-km, 10-Gbps error free transmission without isolator, even with -13dB optical reflection.
Lasers and Electro-Optics, 2005. CLEO/Pacific Rim 2005. Pacific Rim Conference on; 09/2005
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ABSTRACT: Error-free transmission through 10-km single-mode fiber at 10 Gb/s under -13-dB optical reflections has been demonstrated for the first time using a directly modulated 1.3-μm InP-based VCSEL without any optical isolator. The 13-GHz relaxation oscillation frequency and stable polarization suppresses relative intensity noise degradation under optical reflection. Only 1-dB error-free power penalty has been observed with optical reflection set with the worst polarization direction.
IEEE Photonics Technology Letters 09/2005; · 2.19 Impact Factor
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ABSTRACT: A measurement system called laser bar prober for characterizing high-power semiconductor edge-emitting laser bars is described. The laser bar prober is fully automated to handle testing of large numbers of lasers, is multifunctional to measure various laser characteristics and is accurate in predicting performance of fully mounted lasers. The bar prober has been proven to be an effective instrument for screening lasers during manufacturing process as well as an indispensable tool for providing rapid feedback to the development of new laser structures. In this paper, the design of the laser bar prober is described and a few examples of its applications are given; in particular, a time-resolved technique to correlate the measurement data of a laser within a laser bar to those of a fully mounted laser is demonstrated.
Journal of Lightwave Technology 03/2005; 23(2):573- 581. · 2.78 Impact Factor
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ABSTRACT: 1.3-and 1.55-µm vertical-cavity surface-emitting lasers (VCSELs) on InP have been realized. High-reflectivity AlGaInAs–InP lattice matched distributed Bragg reflectors (DBRs) were grown on InP substrates. 1.7 (for 1.3 µm) and 2.0 (for 1.55 µm) mW single mode power at 25 • C, 0.6 mW single mode power at 85 • C and lasing operation at >100 • C have been achieved. 10 Gbit/s error free transmissions through 10 km stan-dard single mode fiber for 1.3-µm VCSELs, and through 15 km nonzero dispersion shift fiber for 1.55-µm VCSELs, have been demonstrated. With the addition of an SOA, 100 km error free transmission at 10 Gbit/s also has been demonstrated through a negative dispersion fiber. No degradation has been observed after over 2500-h aging test. Index Terms—InP, long-wavelength, metal–organic chemical vapor deposition (MOCVD), surface emitting lasers.
IEEE Journal of Selected Topics in Quantum Electronics 01/2005; 11. · 3.78 Impact Factor
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ABSTRACT: We report on highly reliable, high-power, and high-performance 980-nm quantum-well laser chips and modules. Ridge waveguide laser diode chips with 750-mW output power and 500-mW fiber Bragg grating stabilized modules have been achieved and Telcordia-qualified. Long-term reliability tests show a very low failure rate of 400 FIT (failures in time) at 900-mA operating current or 500-mW module power. The kink-free fiber coupled module output power can be as high as 640 mW with grating stabilization, which produces very good wavelength stability and power stability. A further improved structure shows a record continuous-wave rollover chip power of 1.6 W for the 5-μm-wide ridge waveguide laser diodes.
IEEE Photonics Technology Letters 12/2004; · 2.19 Impact Factor
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ABSTRACT: We report a high kink-free facet power of 852 mW and a high single-wavelength facet power of 350 mW for 1060-nm raised-ridge Fabry-Perot (FP) and distributed-feedback (DFB) lasers, respectively.
Semiconductor Laser Conference, 2004. Conference Digest. 2004 IEEE 19th International; 10/2004
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ABSTRACT: The use of a thick quantum well enables coherence-collapse operation of a Bragg grating stabilised laser diode over 110°C temperature range, yielding 975 nm wavelength emission with >40 dB sidemode suppression ratio, <1% power variation, and fibre-output power as high as 293 mW at 15°C and 168 mW at 125°C.
Electronics Letters 09/2004; · 0.96 Impact Factor
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ABSTRACT: Semiconductor pump lasers are an important component in Erbium-doped fiber amplifiers and Raman amplifiers. Thermal management has become one of the major obstacles of pump laser development. Understanding of the thermal behavior of high power laser packages is crucial to the thermal design and optimization of pump lasers. In this paper, we report on the thermal characteristics of a high power pump laser and discuss the issues associated with heat dissipation. The thermal management of high power pump laser modules mainly consists of three aspects. One is the thermal resistance reduction which reduces bulk temperature rise in the laser diode chip. The second is facet temperature control and the third is the thermoelectric cooler (TEC) coefficient of performance improvement. In this paper, the approaches to reduce thermal resistance and facet temperature at the chip level and package level will be reviewed and the thermal design and optimization of the package assembly to improve the TEC coefficient of performance will be discussed.
Thermal and Thermomechanical Phenomena in Electronic Systems, 2004. ITHERM '04. The Ninth Intersociety Conference on; 07/2004
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ABSTRACT: We report high-performance 980-nm ridge waveguide quantum-well lasers with extremely low vertical beam divergence of 13°. A very small aspect ratio of 1.6 is obtained at high operating power of 900 mW. In addition to the more circular beam, low threshold, high efficiency, high characteristic temperature, and high output power of over 1.18 W are achieved. The fiber coupled output power can be as high as 680 mW with fiber Bragg grating stabilization. Excellent wavelength and power stability are also demonstrated.
IEEE Photonics Technology Letters 05/2004; · 2.19 Impact Factor
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04/2002;
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ABSTRACT: Electromagnetic band structure can produce either an enhancement or a suppression of spontaneous emission from two-dimensional (2-D) photonic crystal thin films. We believe that such effects might be important for light emitting diodes. Our experiments were based on thin-film InGaAs-InP 2-D photonic crystals at ambient temperature, but the concepts would apply equally to InGaN thin films, for example. We show that the magnitude of Purcell enhancement factor, F<sub>p</sub>~2, for spatially extended band modes, is similar to that for a tiny mode in a three dimensional (3-D) nanocavity. Nonetheless, light extraction enhancement that arises from Zone folding or Bragg scattering of the photonic bands is probably the more important effect, and an external quantum efficiency >50% is possible. Angle resolved photoluminescence from inside the photonic crystal gives a direct spectral readout of the internal 2-D photonic band dispersion. The tradeoffs for employing various photonic crystal structures in high efficiency light-emitting diodes are analyzed
Journal of Lightwave Technology 12/1999; 17(11):2096-2112. · 2.78 Impact Factor
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ABSTRACT: We describe a promising thin-slab light-emitting diode (LED) design, which uses a highly efficient coherent external scattering of trapped light by a two-dimensional (2D) photonic crystal. The light generation region was an unpatterned heterostructure surrounded by the light extraction region, a thin film patterned as a 2D photonic crystal. A six-fold photoluminescence enhancement was observed compared to an unpatterned thin film LED. That corresponded to 70% external quantum efficiency. © 1999 American Institute of Physics.
Applied Physics Letters 08/1999; 75(8):1036-1038. · 3.84 Impact Factor
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ABSTRACT: Summary form only given. Cascaded second-order nonlinear optical
processes have recently been explored for wavelength conversion
applications. We demonstrate polarization independent wavelength
conversion by cascaded second-order nonlinear optical interactions in
AlGaAs waveguides
Lasers and Electro-Optics, 1999. CLEO '99. Summaries of Papers Presented at the Conference on; 06/1999
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ABSTRACT: Summary form only given. We discuss quasi-phase-matched blue-green
second-harmonic generation in a ZnCdSe waveguide grown on an AlGaAs
template with patterned crystal orientation. The design and fabrication
of the quasiphase-matched waveguide include those ofa template with
periodic domain inversion and those ofa waveguide for confining both the
fundamental and the second-harmonic waves
Lasers and Electro-Optics, 1999. CLEO '99. Summaries of Papers Presented at the Conference on; 06/1999
