OPTICAL TRANSCEIVING DEVICE Russian patent published in 2013 - IPC G02B23/02 G01S7/48 

FIELD: physics.

SUBSTANCE: device has a spherical dome, a flat mirror with an axial bore lying at an angle to the optical axis, a lens which is optically connected to a photodetector, an attenuator and a laser emitter. The attenuator is placed between the spherical dome and the flat mirror and is in form of a cylinder with a conical bore, the output diameter of which is equal to or greater than the diameter of the laser beam from the laser emitter, and the input diameter is determined using the formula: d₁=d+12tgα/2, where d₁ is the input diameter of the conical bore of the attenuator; d is the diameter of the laser beam; l is the distance on the optical axis from the centre of the spherical dome to the input end of the attenuator; α is the angle of view of the lens.

EFFECT: high reliability of protecting the photodetector owing to more complete absorption by the attenuator of laser radiation reflected from the spherical dome and avoiding the attenuator switching process.

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