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Measurements of lattice parameters and compositions for In1−xGaxAsyP1−y lattice matched to InP demonstrate the validity of Vegard’s law for this quaternary. The measured compositional dependence of the band gap shows a bowing parameter smaller than predicted from the previously measured band gaps of the four constituent ternaries.

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We report on low-dark-current IN0.53GA0.47As photodiodes in which generation-recombination current dominates diode leakage up to as high as 100 V. At higher voltages, tunneling currents become dominant, resulting in the soft breakdown characteristic widely observed in these materials. The dark current versus voltage characteristics have been fit to variations in current of over six orders of magnitude and a temperature range greater than 150 K using a theory which includes generation-recombination, tunneling, and shunt components.

Two-dimensional arrays of mutually coherent optical beams are needed in holographic interconnections for both recording and reading gratings. We analyze the use and limitations of binary phase Fresnel lenses to generate beams for these applications. Two known techniques of ion beam milling and thin film deposition are compared to fabricate such lens arrays in SiO(2) and Si(3)N(4). Each lens in the 8 x 8 arrays has a 1.2-mm square aperture with a focal length of 20 mm. Diffraction of a single argon-ion beam into an 8 x 8 array of highly uniform coherent focused beams (with 12-microm spot size) was achieved by the lenses with an efficiency of approximately 30% (41% theoretical limit).