Diffuse Stripe Research Articles

Genetic traits of the mosquito Anopheles gambiae: red stripe, frizzled, and homochromy1.

The expression, inheritance, and linkage relationships of three genetic traits were studied in the malaria vector Anopheles gambiae. Red stripe (Rs) is a common phenotypic polymorphism in numerous A. gambiae populations, whereas frizzled (f) and homochromy1 (hom1) were isolated from (60)Co-irradiated mosquitoes. Red stripe appears as a diffuse stripe of pigment on the dorsum of larvae and pupae and is variable in expressivity and penetrance. Our data demonstrate that Red stripe results from a heterozygous collarless genotype (i.e., c+ c, chromosome 2) and is essentially sex-limited to females. frizzled is a sex-linked recessive semi-lethal identified by deformed lateral larval setae; its lethality manifests as low rates of adult emergence and brief adult survival. frizzled is located on the X chromosome between pink eye and Mosaic, 3 cM from Mosaic and approximately 12 cM from pink eye. Finally, the mutation homochromy1 (hom1) is on chromosome 2 and causes a recessive phenotype that prevents normal darkening of larvae when reared in a black container. Unlike mutants with this characteristic described thus far, the eye color of hom1 mutants is normal. We determined that hom1 is located between Dieldrin resistance and collarless, approximately 3 cM from the latter. We discuss the possibility of differences in male and female recombination values and the range of values that have been observed in test crosses for chromosome 2 markers.

High-power individually addressable monolithic four-beam array of GaAlAs window diffusion stripe lasers

A window structure has been applied, for the first time, to the individually addressable monolithic array of GaAlAs high-power lasers. A 100- mu m spaced array of four window diffusion stripe lasers with a long-cavity of 600 mu m has been fabricated by controllable open-tube two-step diffusion and single-step metalorganic chemical vapor deposition. The window structure and the p-type active stripes with a sufficiently narrow width around 2 mu m are formed by diffusion of zinc, which just passes through an n-type active layer. CW output power up to 120 mW without catastrophic damage and a threshold current around 30 mA have been achieved for each element in the wavelength range of 830 nm. Excellent uniformity of device characteristics across an array chip is confirmed. Thermal crosstalk of the elements operating simultaneously is investigated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

780 nm low threshold current laser fabricated by two-step, solid-phase Zn diffusion

A Zn diffusion stripe laser is fabricated by the metalorganic chemical vapour deposition and the open-tube, two-step, solid-phase diffusion technique. The threshold current is 9.4 mA and the lasing wavelength is 780 nm at 20°C. The laser operates in the fundamental transverse mode and the astigmatic distance is less than 1 μm. The laser has operated for over 1000 h at 60°C with a power of 3 mW.

High-power 780 nm window diffusion stripe laser diodes fabricated by an open-tube two-step diffusion technique

High-power and low-threshold-current GaAlAs lasers with a simple window structure fabricated by controllable open-tube two-step diffusion and single-step metalorganic chemical vapor deposition are discussed. The window structure and the waveguide with a narrow width around 2 mu m are formed by diffusion of zinc, which just passes through an n-type active layer. CW output power up to 134 mW without catastrophic damage and a threshold current of 17 mA have been achieved. A maximum output power density of 16 MW/cm/sup 2/ is estimated. A stable fundamental transverse mode of up to 100 mV in the wavelength range of 780 nm is obtained. Excellent uniformity of device characteristics is confirmed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Flow effects in epitaxial autodoping

A quantitative model has been developed to account for the flow effects in epitaxial autodoping for chemical-vapor-deposited films. Analytical expressions are derived for the autodoping variations along and against the direction of flow arising from a diffusion stripe in the substrate. These expressions relate the maximum concentration in the lateral autodoping peak to the distance from the autodoping source and to the carrier gas velocity. Experimental verification of the model is obtained for arsenic autodoping in silicon epitaxial films, which indicates that boundary layer effects are not predominant in the autodoping phenomenon. The analysis also yields a value of 2.5 cm2/sec for the arsenic vapor diffusivity in hydrogen at 1150 °C.