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K. Fujikawa

Bio: K. Fujikawa is an academic researcher from Mitsubishi Electric. The author has contributed to research in topics: Laser & Semiconductor laser theory. The author has an hindex of 3, co-authored 4 publications receiving 58 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the fabrication procedure, designing of an active region and a p-n-p-n current blocking structure, characteristics and the aging results of an InGaAsP/InP buried crescent (BC) laser diode are described.
Abstract: The fabrication procedure, designing of an active region and a p-n-p-n current blocking structure, characteristics and the aging results of an InGaAsP/InP buried crescent (BC) laser diode are described. The BC laser diodes exhibit high laser performances, such as a low-threshold current, a fundamental transverse mode oscillation with linear light output-current characteristics. CW operation at as high as 100°C is achieved with a junction up configuration as a result of the improvement in the current blocking structure. A stable CW operation at 80°C has been realized with a constant optical output power of 5 mW.

28 citations

Journal ArticleDOI
TL;DR: In this article, a degradation of the buried crescent (BC) InGaAsP/InP laser was found when the p−n junction plane coincides with the surface exposed in the high-temperature H2 ambient before the melt contact during the liquid phase epitaxial growth.
Abstract: We have found a degradation of the buried crescent (BC) InGaAsP/InP lasers that occurs when the p‐n junction plane coincides with the surface exposed in the high‐temperature H2 ambient before the melt contact during the liquid phase epitaxial growth. To eliminate the degradation, we have fabricated a new structure of the BC laser and have obtained stable cw operation at 80 °C.

21 citations

Journal ArticleDOI
H. Higuchi1, E. Oomura1, R. Hirano1, Y. Sakakibara1, H. Namizaki1, W. Susaki1, K. Fujikawa1 
TL;DR: In this paper, electroluminescent mode aging at high-temperature and high-current levels is used for selecting long-lived InGaAsP 1.3 μm lasers.
Abstract: It is found that electroluminescent mode aging at high-temperature and high-current levels is useful for selecting long-lived InGaAsP 1.3 μm lasers. Lasers selected by this screening have little change in threshold current or forward voltage through the aging test at an elevated temperature with constant light-output power.

8 citations

Proceedings ArticleDOI
01 Jan 1983
TL;DR: In this paper, a new BC structure (displaced BC, D-BC) with optimized device parameters such as the dimensions of the active region and the doping levels of the constituent layers is presented.
Abstract: The main purpose of this study is to realize a highly reliable InP/InGaAsP lasers even at elevated temperatures. We present and demonstrate a new BC structure (displaced BC, D-BC) with optimized device parameters such as the dimensions of the active region and the doping levels of the constituent layers. A stable long life operation for more than 4,000 hours in automatic power control (APC) mode operation at a temperature of 80° C is obtained in these new lasers. The life time of the lasers are estimated to be 8 \times 10^{4} hours( ≃ 9 years).

1 citations


Cited by
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Journal ArticleDOI
E. Kuphal1
TL;DR: In this paper, a comprehensive review of liquid phase epitaxy (LPE) of semiconductors is presented, and the advantages and weaknesses of LPE with respect to device applications in comparison with competing methods are discussed.
Abstract: This paper presents a comprehensive review of the method of liquid phase epitaxy (LPE) of semiconductors. In Sect. 1 the physical principles including diffusion-limited growth and solid-liquid phase diagrams are treated in detail. In Sect. 2 technological aspects and various kind of growth systems including industrial versions are described. Section 3 summarizes the relevant properties of LPE grown layers. Section 4 contains the application of LPE to the material system InP/InGaAs/InGaAsP as a model system. In Sect. 5 the advantages and weaknesses of LPE with respect to device applications in comparison with competing methods are discussed, and finally we attempt to predict the future direction of LPE.

101 citations

Journal ArticleDOI
TL;DR: In this article, a defect mechanism associated with the gradual degradation of CSBH is discussed, which is characterized by a gradual increase in room-temperature threshold current, a decrease in external quantum efficiency, typically a drop in peak value of dL/dI greater than 25%, and a large peak in forward voltage at low current, indicating a change in junction characteristics.
Abstract: Channeled-substrate buried heterostructure (CSBH) lasers which were purged from populations undergoing high reliability qualification have been studied in detail. Gradual and rapid degradation mechanisms leading to accelerated aging failure modes have been analyzed by transmission electron microscopy, convergent beam electron diffraction, electroluminescence, energy dispersive x-ray analysis, and chemical etching. The gradual degradation mode of CSBH lasers is characterized by (1) a gradual increase in room-temperature threshold current; (2) a decrease in external quantum efficiency, typically a drop in peak value of dL/dI greater than 25%; (3) a drop in forward voltage at low current, indicating a change in junction characteristics; (4) a large peak inI(dV/dI) below threshold (at around 3 mA); and (5) an enhancement in the peak in I2(d2V/dI2) at laser threshold. A defect mechanism associated with the gradual degradation begins with a nucleation of extrinsic dislocation loops along the V-groove {111} p-n–type sidewall interfaces between the Cd-diffused p-InP and liquid-phase-epitaxial-grown n-InP buffer inside the groove. These dislocation loops subsequently grow out of the interfaces into the n-InP buffer region in the direction of minority-carrier injection, indicating a nonradiative recombination-assisted defect growth process. For those loops which enter the quaternary active region near the tip of the active crescent, the growth rate along the (001) and (010) planes is greatly enhanced and the loops eventually cut across the active stripe and become dark-line defects, as confirmed by electroluminescence. Nucleation of dislocation loops is not observed along the {111} p-p–type sidewall interfaces above the active stripe. The fact that the dislocation loops are all extrinsic in nature implies that the {111} sidewall interfaces as well as the quaternary active region contain a high density of interstitials. The possible causes for the generation and growth of the dislocation loops and the high density of point defects are discussed. The rapid degradation mode of the CSBH laser is characterized by a sudden drop in light intensity during the aging process. The associated defect mechanism starts with localized melting at the mirror facet or inside the lasing cavity. A metal-rich droplet subsequently forms which propagates along the center of the active stripe in the direction towards the cavity center via a meltback-regrowth process; i.e., material melts in front of the droplet and regrows after it propagates by. The nonideal condition of regrowth results in the formation of a wormlike defect composed of a cylinder of defective materials bounded by an off-stoichiometric interface. The wormlike defect is dark under electroluminescence. Complicated dislocation structures can also be grown from the wormlike defect under a nonradiative recombination-assisted defect growth process. These phenomena are presented and discussed.

49 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the maximum CW output power in GaInAsP 1.3μm V-grooved inner stripe on P-substrate (VIPS) lasers considering both cavity length and facet reflectivity.
Abstract: Maximum CW output power was investigated in GaInAsP 1.3μm V-grooved inner stripe on P-substrate (VIPS) lasers considering both cavity length and facet reflectivity. Long-cavity lasers show a strong dependence of maximum output power on front reflectivity. A CW light output over 200 mW was obtained at room temperature using a 700 μm long cavity laser with 5 and 98 percent reflectivity of the front and rear facets, respectively. The fundamental transverse mode operation was confirmed up to 170 mW. A coupled power over 110 mW into a single-mode fiber was achieved with a coupling efficiency of 58 percent. We have verified the high reliability under high power levels, as high as 75 percent of the maximum CW output powers at room temperature.

45 citations

Journal ArticleDOI
TL;DR: In this paper, a failure mode connected to the active region, not to the burying region, is observed in InGaAsP/InP buried heterostructure lasers, and degradation is related to a decrease in the carrier lifetime or decrease in nonradiative lifetime due to degradations at the edges of the active regions.
Abstract: In InGaAsP/InP buried heterostructure lasers, a failure mode connected to the active region, not to the burying region, is observed. The degradation is related to a decrease in the carrier lifetime or a decrease in nonradiative lifetime due to degradations at the edges of the active region. Practically, the bad devices may be screened out by the hard screening method, however, the failure mode could determine the reliability of the devices under high‐temperature or high‐power operation, so care should be taken during forming the mesa and a regrowth of the burying layer.

41 citations

Journal ArticleDOI
TL;DR: In this paper, the mechanism of current leakage at high temperatures in InGaAsP/InP buried heterostructure (BH) lasers with p-n-p-n current blocking structures is analyzed using two-dimensional computer simulation.
Abstract: The mechanism of current leakage at high temperatures in InGaAsP/InP buried heterostructure (BH) lasers with p-n-p-n current-blocking structures is analyzed using two-dimensional computer simulation. It is found that no junction in the blocking layers is reverse-biased and that current confinement is due to electrically floating regions in the blocking structures. To minimize the leakage current in these BH lasers, it is necessary to decrease the device width and the connection length between the blocking and cladding layers and to increase the doping level and thickness of the blocking layers. >

39 citations