Societe Anonyme De Telecommunications

Yves Carpentier

Andre Gauthier

Michel Royer

An HgCdTe avalanche photodiode for use at ambient temperature comprises an Hg.sub.1-x Cd.sub.x Te crystal substrate in which x is chosen between substantially 0.35 and substantially 0.5, a PN junction is formed in the substrate with low concentrations in the vicinity of the junction, by impurity penetration from a polished and chemically etched surface and the P zone is illuminated. A guard band is provided around the PN junction. The dark current of the photodiode is less than 0.1 .ANG./cm2 at ambient temperature and the excess noise factor is less than 0.4. The photodiode of the invention is used for detecting signals transmitted along fluorated glass optical fibers, for example.

HgCdTe avalanche photodiode

The invention relates to a photoconducting detector in optical immersion, comprising a detector wafer in Hg.sub.1-x Cd.sub.x Te, on a quartz substrate, and a hemispherical lens in CdTe, assembled on each other by a layer of photosensitive resin whose thickness is calibrated by two shims. The detector is advantageously used for the evaluation of targets.

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Savigny s/Orge, France

Yves Carpentier