InGaAsP/InP BH lasers on p-type InP substrates

A 1.55 ?m InGaAsP/InP BH laser is achieved on a p-type InP substrate resulting in a simple fabrication process. A threshold current as low as 40 mA under CW operation and a pulsed power rating of several hundred mW at 8 A peak current are achieved in buried-heterostructure lasers.     

Facet oxidation of InGaAsP/InP and InGaAs/InP lasers

The facet oxidation of InGaAsP/InP and InGaAs/InP lasers is investigated after aging under high constant optical output power or high current stress. Facet oxidation in InGaAsP/InP lasers is negligibly small under several thousand hours of practical operation. The thickness of oxide film increases in proportion to optical output power and logarithm of aging time. The growth rate of facet oxide film weakly depends on the junction temperature and the activation energy is estimated to be 0.07 eV within a experimental range between 25 and 150°C. The facet of InGaAs/InP lasers are oxidized more easily than that of InGaAsP/InP lasers but are about two orders of magnitude more stable against oxidation than that of AlGaAs/GaAs lasers.     

GaInAsP/InP surface-emitting lasers with current confining structure

In order to reduce the threshold current of GaInAsP/InP surface-emitting (SE) lasers, we search for an effective current confining structure and examined several types; round-low-mesa, round-high-mesa/polyimide-buried, buried-heterostructure (BH), and planar-buried-heterostructure (PBH). The minimum threshold current was reduced down to 18 mA at 77 K and the threshold current density was estimated to be reduced to 3 kA/cm². The operating temperature has been raised to -10°C (263 K). The longitudinal-mode hopping was first observed for GaInAsP/InP SE lasers. The effective refractive index for GaInAsP/InP SE lasers was 4-5, that was almost the same as conventional edge-emitting lasers.     

Characteristics of diffused-stripe InP/InGaAsP/InP lasers emitting around 1.55 µm

Fabrication and lasing characteristics of InGaAsP/InP lasers emitting around 1.55 μm are described. Zn-diffused stripe-geometry lasers with emission wavelengths in the1.53-1.60mum range were fabricated from InP/InGaAsP/InP DH epitaxial wafers prepared by a low temperature LPE technique. The dependence of the lasing charaeteristics on the stripe width was examined. The lowest threshold current (≃160 mA under CW operation at 27°C) was obtained for a laser with a 13 μm stripe. CW operation of the laser has been achieved at a heat-sink temperature as high as 53°C. For sufficiently narrow stripe widths (simeq6 mum), fundamental-transverse mode and single-longitudinal mode operation was obtained under CW operation. Moreover, the lasers have good high-frequency performance. The lasers showed excellent dynamic properties without waveform distortion under high-frequency (800 Mbits/s) large-signal pulse modulation. The full width at half maximum of the longitudinal mode envelope was approximately 30 Å at 800 Mbits/s.     

Compressively strained 1.3 μm InAsP/InP and GaInAsP/InP multiplequantum well lasers for high-speed parallel data transmission systems

Turn-on delay times in the pulse response of compressively strained InAsP/InP double-quantum-well (DOW) lasers and GaInAsP/InP multiple-quantum-well (MQW) lasers emitting at 1.3 μm were investigated. DQW lasers with 200-μm cavity length and high-reflection coating achieved both a very low threshold current (1.8 mA) and a small turn-on delay time (200 ps), even under a biasless 30-mA pulse current. Compressively strained or lattice-matched GaInAsP MQW lasers and GaInAsP double-heterostructure (DH) lasers were also fabricated and compared. It was observed that the carrier lifetime was enhanced for InAsP DQW lasers and strained GaInAsP MQW lasers compared to the lattice-matched GaInAsP MQW lasers and conventional double-heterostructure lasers. To explain this increase in the carrier lifetime, the effect of the carrier transport on the carrier lifetime was studied. The additional power penalty due to the laser turn-on delay was simulated and is discussed     

1.5 ?m region InP/GaInAsP buried heterostructure lasers on semi-insulating substrates

InP/GaInAsP buried heterostructure (BH) lasers for the 1.5 ?m region have been fabricated on semi-insulating InP substrates. The threshold current of the lasers is as low as 38 mA under CW operation at 25°C, which is nearly the same as for BH lasers fabricated on n-type InP substrates.     

High-speed InGaAsP/InP multiple-quantum-well laser

The authors describe practical high-speed InGaAsP/InP lasers based on compressively strained quantum wells. Buried heterostructure lasers with threshold currents of 10 mA and slope efficiencies of 0.23 mW/mA are used. A modulation bandwidth of 20 GHz is obtained at a low drive current of 90 mA. A K factor of 0.25 ns is obtained and the intrinsic bandwidth of these lasers is estimated at 35 GHz     

GaInAsP/InP laser with monolithically integrated monitoring detector

Monolithic fabrication of a GaInAsP/InP laser with an etched mirror and monitoring detector is reported. Stripegeometry lasers operating at wavelengths of ~1.3 ?m with threshold current of only 300 mA have been obtained. The monitoring detector on the same InP substrate was confirmed to operate with high sensitivity, comparable with that of an external Ge photodiode.     

Room-temperature CW operation of 1.3 ?m distributed-feedback GaInAsP/InP lasers

Distributed-feedback GaInAsP/InP lasers with a low threshold current emitting at 1.3 ?m have been successfully fabricated. A minimum CW threshold current of 66 mA was obtained at room temperature. The temperature coefficient of lasing wavelength was 1 ?/°C, which is about a fifth of that for Fabry-Perot lasers. A stable single longitudinal mode was obtained up to 52°C in a p-side-up configuration.     

Room-temperature c.w. operation of InP/InGaAsP/InP double heterostructure diode lasers emitting at 1.55 ?m

Room-temperature c.w. operation has been achieved for stripe-geometry double heterostructure InP/InGaAsP/InP diode lasers emitting at 1.55 ?m. The heterostructures were grown by l.p.e. on (100) InP substrates, and stripes were defined by the conventional planar-stripe structure. The room-temperature (20°C) c.w. threshold current ?250 mA for a 6 ?m wide by 200 ?m long cavity.     

Low-threshold-current distributed-feedback InGaAsP/InP CW lasers

Distributed-feedback buried-heterostructure InGaAsP/InP lasers with room temperature CW threshold current as low as 50 mA, corresponding to a current density of 2.3 kA/cm2, are presented. CW operation in the temperature range from ?20°C to 58°C was confirmed.     

Direct observation of the spatial hole burning and the saturation of the spontaneous emission in InGaAsP/InP lasers

The saturation behavior of the spontaneous emission intensity from a diffused-stripe InGaAsP/InP laser is studied. In InGaAsP/ InP DH lasers, a spontaneous emission can be observed through the InP substrate without any optical loss. The spatial distribution and the spectrum of the emission were directly observed from the substrate surface. The spatial hole burning was observed in the wider stripe lasers but in the case of narrow stripe lasers, the spontaneous emission almost uniformly saturates. The spectrum of the emission from the center of the narrow stripe lasers was analyzed and it was confirmed that, above the threshold current, the spectra in the lasing region saturated over the entire spectral region.     

Integrated external-cavity InGaAs/InP lasers using cap-annealing disordering

InGaAs/InP multiple-quantum-well lasers were integrated with low-loss waveguides in the long-wavelength region using a cap-annealing disordering technique which does not require a regrowth process. The coupling efficiency between them does not increase the threshold current of the lasers. The optical loss in the waveguide was 7.8 cm/sup -1/ and was due to free-carrier absorption in the cladding layers.<>     

Room temperature c.w. operation of InGaAsP/InP heterostructure lasers emitting at 1.56 ?m

Room-temperature c.w. operation of InGaAsP/InP heterostructure lasers grown by liquid-phase epitaxy was achieved at 1.56 ?m. An active InGaAsP layer was essentially sandwiched by InP, though a thin InGaAsP buffer layer was deposited to prevent the melt-back of the active layer. Threshold current was typically 300 mA for a 17 ?m wide oxide-defined stripe laser.     

Phase-locked arrays of buried-ridge InP/InGaAsP diode lasers

Phased-locked arrays of buried-ridge InP/InGaAsP diode lasers, emitting at 1.3 μm, were investigated both theoretically and experimentally. These arrays consist of index-guided buried-ridge lasers which are coupled via their evanescent optical fields. The field patterns and the modal gains of the array supermodes were calculated by using a simple waveguide model. The theoretical results show that buried-ridge arrays can be designed such that only the fundamental supermode is excited. In that case, the array lasers are coupled in-phase, which yields single-lobed, diffraction limited far-field patterns. The buried-ridge InP/InGaAsP arrays were grown by liquid phase epitaxy. These arrays exhibited single-lobed beams less than 4° in width up to more than twice the threshold current. Comparison of the measured field patterns and the calculated ones indicated that these arrays oscillated mainly in the fundamental supermode.     

Hybrid LPE/MBE-grown InGaAsP/InP DFB lasers

InGaAsP/InP distributed-feedback (DFB) lasers operating at 1.5 ?m have been successfully fabricated by a hybrid growth technique of liquid phase epitaxy (LPE) and molecular beam epitaxy (MBE). A threshold current of 180 mA at 23°C and single-longitudinal-mode operation have been obtained.     

High-quality 1.3 ?m GaInAsP/InP BH-DFB lasers with first-order gratings

High-quality 1.3 ?m GaInAsP/InP BH-DFB lasers have been demonstrated. The threshold current was 16 mA and the differential quantum efficiency was 25% per facet. A stable single-longitudinal-mode oscillation was obtained, both up to four times the threshold current and up to 85°C. These results are comparable or superior to reported results of Fabry-Perot BH lasers.     

1.5mm腔长InAs/InP量子点激光器镜面外腔光谱特性研究

基于研制的1.5mm腔长InAs/InP共面条状量子点激光器,搭建了其镜面外腔结构,并对其光谱特性进行了测试,获得了镜面外腔周期性调制光谱,并在周期性的产生、多模激射和模式随电流的变化等方面对其光谱特性进行了分析研究。相比以前为获得单模使用的超短腔长超短外腔量子阱激光器,长腔长InAs/InP量子点激光器表现出较小的模式压缩比,更容易发生多模激射。     

LPE growth of 1.3 ?m InGaAsP CW lasers on (110) InP substrates

Room temperature CW operation and threshold current densities below 1000 A/cm2 have been achieved near 1.3 ?m wavelength with InP/InGaAsP/InP DH lasers grown by liquid phase epitaxy on (110)-oriented InP substrates.     

Planar buried heterostructure InP/GaInAs lasers grown entirely by OMVPE

GaInAs/InP planar buried heterostructure (PBH) lasers with semi-insulating blocking layers were grown in an `all? atmospheric OMVPE system. These layers had current thresholds as low as 35 mA and differential quantum efficiencies of ?16% at a wavelength of 1.64 ?m. The maximum power output was 80 mW pulsed and 8mWCW.