In the past few years, GaInNAsSb has been found to be a potentially superior material to both GaInNAs and InGaAsP for communications wavelength laser applications. It has been observed that due to the surfactant role of antimony during epitaxy, higher quality material can be grown over the entire 1.2 – 1.6 µm range on GaAs substrates. In addition, it has been discovered that antimony in GaInNAsSb also works as a constituent that significantly modifies the valence band. These findings motivated a systematic study of GaInNAsSb alloys with widely varying compositions. Our recent progress in growth and materials development of GaInNAsSb alloys and our fabrication of 1.5 – 1.6 µm lasers are discussed in this paper. We review our recent studies of the conduction band offset in (Ga,In) (N,As,Sb)/GaAs quantum wells and discuss the growth challenges of GaInNAsSb alloys. Finally, we report record setting long wavelength edge emitting lasers and the first monolithic VCSELs operating at 1.5 µm based on GaInNAsSb QWs grown on GaAs. Successful development of GaInNAsSb alloys for lasers has led to a much broader range of potential applications for this material including: solar cells, electroabsorption modulators, saturable absorbers and far infrared optoelectronic devices and these are also briefly discussed in this paper.

Development of GaInNAsSb alloys : Growth, band structure, optical properties and applications

We demonstrate the 1.58 mu m emission at room temperature from a metamorphic In0.6Ga0.4As quantum well laser grown on GaAs by molecular beam epitaxy. The large lattice mismatch was accommodated through growth of a linearly graded buffer layer to create a high quality virtual In0.32Ga0.68As substrate. Careful growth optimization ensured good optical and structural qualities. For a 1250x50 mu m(2) broad area laser, a minimum threshold current density of 490 A/cm(2) was achieved under pulsed operation. This result indicates that metamorphic InGaAs quantum wells can be an alternative approach for 1.55 mu m GaAs-based lasers. (C) 2007 American Institute of Physics.

1.58 mu m InGaAs quantum well laser on GaAs

Starting from the growth of high-quality 1.3μmGaInNAs∕GaAs quantum well (QW), the QW emission wavelength has been extended up to 1.55μm by a combination of lowering growth rate, using GaNAs barriers and incorporating some amount of Sb. The photoluminescence properties of 1.5μm range GaInNAsSb∕GaNAs QWs are quite comparable to the 1.3μm QWs, revealing positive effect of Sb on improving the optical quality of the QWs. A 1.59μm lasing of a GaInNAsSb∕GaNAs single-QW laser diode is obtained under continuous current injection at room temperature. The threshold current density is 2.6kA∕cm2 with as-cleaved facet mirrors.

GaAs-based room-temperature continuous-wave 1.59 {mu}m GaInNAsSb single-quantum-well laser diode grown by molecular-beam epitaxy

Electrically pumped, C-band vertical cavity surface emitting lasers (VCSELs) grown on GaAs are reported for the first time. The VCSELs employed three GaInNAsSb quantum wells separated by GaNAs barriers. Pulsed lasing was observed at 1534 nm, in the ITU C-band, when cooled. These lasers exhibit the longest wavelength reported to date for electrically pumped VCSELs grown on GaAs substrates.

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GaInNAsSb/GaAs vertical cavity surface emitting lasers at 1534 nm

Molecular beam epitaxy growth of 1.55 μm GaInNAs(Sb) double quantum wells with bright and narrow photoluminescence

The first 1.55 /spl mu/m room-temperature continuous-wave (CW) operation of GaAs-based laser diodes utilising GaInNAsSb/GaNAs double quantum well active regions grown by molecular beam epitaxy is reported. In electrically-pumped CW operation the narrow ridge waveguide devices have a room temperature lasing wavelength of 1550 nm near threshold, increasing to 1553 nm at thermal rollover. The CW threshold current was 132 mA for a 3/spl times/589 /spl mu/m device, with a characteristic temperature of 83 K, measured in pulsed mode between 20 and 70/spl deg/C.

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Room-temperature continuous-wave operation of GaInNAsSb laser diodes at 1.55 [micro sign]m

GaInNAsSb/GaNAs double quantum well ridge waveguide laser diodes with room temperature lasing wavelength of 1532 nm are reported. The devices exhibit leakage-corrected threshold current densities as low as 969 A cm−2 per quantum well in pulsed mode, with characteristic temperatures as high as 90 K.

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1.53 [micro sign]m GaInNAsSb laser diodes grown on GaAs(100)

The properties of a high-characteristic temperature (T0=155K) 1.3-mum GaInNAs-GaAs laser are presented with an emphasis on laser dynamic characteristics evaluated by linewidth enhancement factor and relative intensity noise. It is found that the relatively high differential gain of GaInNAs-GaAs quantum wells leads to a small linewidth enhancement factor of 2.8, indicating a small magnitude of frequency modulation with modulation current. The relative intensity noise measurements indicate a relaxation frequency of 4.7 GHz at a moderate bias current, from which the maximum intrinsic modulation bandwidth was calculated to be 9.7 GHz. The experimental determination of the low linewidth enhancement factor and high relaxation frequency reinforce the potential of dilute nitride lasers for high-speed directly modulated fiber links

Intrinsic Dynamic Properties of High-Characteristic Temperature GaInNAs Laser Diodes Operating at 1.3 $\mu$ m

Synthesis of coal tar pitch-derived heteroatom-doped porous carbon materials for aqueous zinc-ion hybrid supercapacitors

We demonstrate for the first time a low-threshold and narrow-linewidth multi-electrode distributed feedback laser with third-order surface gratings operating at 1550 nm. Stable single-mode operation is obtained with SMSR of over 50 dB.

Xia Zhang

Papers

Room-temperature continuous-wave operation of GaInNAsSb laser diodes at 1.55 [micro sign]m

1.53 [micro sign]m GaInNAsSb laser diodes grown on GaAs(100)

Intrinsic Dynamic Properties of High-Characteristic Temperature GaInNAs Laser Diodes Operating at 1.3 $\mu$ m

Synthesis of coal tar pitch-derived heteroatom-doped porous carbon materials for aqueous zinc-ion hybrid supercapacitors

Low-threshold and narrow linewidth two-electrode MQW laterally coupled distributed feedback lasers at 1550 nm