Low temperature behaviour of InGaAsP laser diode is studied. The laser is a Fabry-Perot type with a Buried Heterostructure. A large improvement of threshold current is obtained as the temperature decreases. The exponential variation of Ith is verified and a T0 value of 69K is deduced. The intrinsic resonant frequency is measured with noise analysis. This resonance varies as the square root of the net injected current. The slopes of these curves are found to increase dramatically with decreasing temperature. The 3 dB bandwidth experiments are also performed, leading in the same way, to a large increase of the slopes with cooling but package parasitics limit the maximum achievable bandwidth. The influence of the laser parasitics, such as the roll-off phenomenum, is also underlined.

The monolithic integration of optoelectronic devices with microwave impedance matching networks is presented. These are a GaInAs photodiodes and a GaInAsP buried ridge stripe structure laser emitting at 1.3 mu m; both are fabricated on semi-insulating InP substrate. The matching networks, consisting of reactive components, have been designed to match these devices to 50 Omega at 6 GHz with a bandwidth close to 10%. Compared to an unmatched link, an improvement of 12 dB at 6 GHz is theoretically obtained; experimentally, it has been measured to 11.4 dB at 5.6 GHz.<>

The gain compression and phase-amplitude coupling factors are measured along with the differential gain in GaInAs/GaInAsP quantum well lasers with three, five and seven wells. Results are compared with those obtained for a conventional bulk laser of the same quaternary material. The ultimate modulation bandwidth deduced from the measurements is shown to increase with the number of wells. For the seven well laser, the ultimate modulation bandwidth is found to reasonably approach that obtained for the bulk laser while the phase-amplitude coupling factor is 2.6 times smaller.

The authors report optical investigations of an InGaAs-InGaAsP-InP double-step quantum well designed to provide a sensitive measurement of the band offsets in this technologically important system. The results yield a conduction band offset to bound-gap difference ratio of 43+or-2% which coincides with recent estimates for the InGaAs-InP heterojunction.

We report optical investigations of an InGaAs-InGaAsP-InP double step quantum well designed to provide a sensitive measurement of the band offsets in this technologically important system. Our results yield a conduction band offset to band gap difference ratio of 43±2 %. This value coincides with recent determinations of this parameter in the InPInGaAs heterojunction.

Losses as low as 0.4 ± 0.2 dB/cm and electro-optical modulation efficiencies as high as 5°/V/mm have been obtained in single mode waveguides employing a novel buried structure in GaInAsP/InP grown by LPMOCVD and processed by selective chemical etching. Such modulators are potentially excellent candidates for integrated optoelectronics.

Continuous and pulsed phase-locked operation of a high power GaInAsP-InP semiconductor laser emitting at 1.3 μm has been achieved. The laser consists of a seven-striped array of ridge-island lasers fabricated by a two-step low-pressure metalorganic chemical vapor deposition growth technique. Linear output powers greater than 300 mW (pulsed) and 120 mW (cw) have been obtained with no facet coatings. The far-field full widths at half power, both parallel and perpendicular to the junction plane, were 3° and 45°, respectively, at 10 mW (at 20 °C) which is evidence for strong stripe-to-stripe coupling.

A second diffusion of Zn has been observed in GaAs in the low-concentration range. The behaviour is similar to that of double diffusion in InP. The effect of zinc activity in the vapour phase has been studied using a semiclosed-box system. The observed profiles of Zn have been explained using a model of varying charge transfer by vacancy centers during interstitial-substitutional interchanges.

Liquid sources consisting of the In-Zn-As ternary system have been successfully used for the diffusion of Zn in GaAs by the semiclosed-box method. The surface concentration and junction depth were easily controlled over a wide range of source composition. The experimentally observed effects of the zinc and arsenic fractions in the source on the diffusion agree well with a model derived from interstitial-substitutional interchange.

A simple model of diffusion involving the internal electric field and the presence of neutral effects was developed. The interstitial-substitutional mechanism has been found to be very sensitive to the carrier concentration in the substrate which controls the shape of the diffusion profile and accelerates or retards the diffusion process. The variations of the junction depth with substrate doping has been attributed to the equilibrium shift between interacting species rather than to the internal field. From a detailed analysis of the zinc and cadmium diffusion profiles in InP, the presence of neutrals and the interstitial charge state have been identified.

The lasing characteristics of quantum well and double heterostructure lasers are compared for the GaAs/GaAlAs and GaInAs/InP materials systems. The poorer performance of GaInAs/InP quantum well lasers is shown to be due to carrier heating linked to Auger recombination. However, low-temperature measurements reveal that in other respects these lasers are well behaved.

GaInAsP-InP distributed feedback (DFB) lasers emitting at 1.57 μm have been fabricated on material grown completely by low-pressure metalorganic chemical vapor deposition (LP-MOCVD). The CW threshold current of 60 mA and an output power of 6 mW per facet at room temperature have been obtained. The lasing wavelength λLunder CW operation showed a temperature coefficient (d_{\lambdaL}/dT) of 0.9 Å/°C...

Room temperature pulse operation and continuous wave (CW) operation in the 1.2–1.6 μm region have been achieved in GaInAsP-InP DH lasers fabricated on material grown by LPMOCVD. Threshold currents density as low as 430 A/cm2 (cavity length of 950 μm) have been measured for devices emitting at 1.3 μm. Threshold current densities of 1060 A/cm2 (cavity length of 400 μm) have been obtained for devices emitting at 1.55 μm, with active layer thicknesses of 0.22 μm. Values of T0 between 60 and 70 K have been obtained. Fundamental transverse mode oscillation has been achieved (for CW operation) up to an output power of 10 mW. The preliminary results on the aging test are most encouraging and demonstrate that the LPMOCVD lasers emitting at 1.2–1.6 μm have comparable degradation rates to those of LPE lasers suggesting the LPMOCVD technique is promising for large scale production of laser diodes.

A novel semiclosed diffusion technique for III-V semiconductors has been developed giving ease of control of the operating and junction depth. The secondary-ion mass-spectrometry atom profiles and carrier-concentration profiles have been used to develop a mechanism involving the temperature dependence of neutral Zn formation. Doubly-ionized interstitials are thought to be the diffusion species.

A GaInAsP buried ridge structure laser (BRSL) emitting at 1.5 μm and fabricated on material grown entirely by LP-MOCVD is described for the first time in the letter. Threshold currents of 40 mA DC and an output power up to 15 mW have been obtained at room temperature. CW operation up to 60°C has been achieved.

Continuous wave operation of 1.57-μm distributed feedback lasers fabricated on material grown by two-step low-pressure metalorganic chemical vapor deposition growth process is reported for the first time. Room-temperature continuous wave threshold currents as low as 60 mA have been measured for devices with cavity length of 300 μm and stripe width of 5 μm. Single longitudinal mode operation at fixed mode was obtained under the continuous wave condition, in the temperature range 9–90 °C, with the wavelength shift of 0.9 Å/°C. A stop band of 25 Å in which no resonance mode emission existed, was observed in the output spectrum of the distributed feedback laser.

In this paper, we describe the growth of abrupt heterojunctions and very thin GaAs and GaAlAs layers for use in quantum well lasers or TEGFET (two-dimensional electron-gas field effect transistors) structures. SIMS measurements have been performed which confirm that the growth rate measured for thick layers (1 to 10 μm) can be used to estimate the thickness of very thin layers (<100 Å) with a good accuracy. Luminescence data from GaAlAs/GaAs/GaAlAs quantum wells shows that there is probably some random compositional fluctuation in the GaAlAs quantum well barrier layers which leads to a broadening of the luminescence peak and a shift to lower energy. These quantum wells form the active layer of separate confinement heterostructure (SCH) and graded refractive index (GRIN) SCH quantum well laser structures. We will review the results of our study of these lasers explaining the separate roles of the GRIN and quantum well. New results will be given showing how the value of T0 can be improved by increasing, the number of quantum wells in the active layer.

The letter describes the characteristics of stripe lasers formed in GaAs/GaAlAs single-quantum-well graded-composition separate-confinement heterostructures (GRIN-SCH) grown by low-pressure organometallic vapour phase epitaxy (LP-OMVPE). We show that the low threshold current density that has been achieved with the GRIN-SCH structure allows low threshold currents (38 mA) to be achieved in a simple...

In a recent publication we gave preliminary results on the lasing characteristics of a GRIN-SCH GaAs/GaAlAs laser grown by OM-VPE. The parameters of this single quantum well laser have now been further optimised, and for a quantum well thickness of 60 Å, with outer confinement layers composed of Ga0.4Al0.6As, significantly lower threshold current densities have been achieved. For a broad-area lase...

We report on the aging of a continuous-wave (CW) GaInAsP/InP double-heterostructure laser emitting at 1.5 μm, grown for the first time by MOCVD. This device has been operated at room temperature for more than 104 h without significant degradation.