Photodiode with Selective Bidimensional Sensitivity 

The photodiode with selective bidimensional sensitivity (quadrant-photodiode) elaborated on the basis of InP-InGaAsP heterostructures with InGaAsP thick wide-gap frontal layer assures selective sensitivity to l=1.06 mm for atmosphere telecommunications systems usage. The photodiode structure is divided into 6 elements: four elements having circular sector form used for determination of the incident light signal position; a circumferential guard ring, which signalizes the incident signal emission moment; an integrated central detector with small area allows to detect high-frequency optic signals.

Innovative Aspect and Main Advantages:
The simultaneous combination of selective, coordinate and high-frequency sensitivity in a single device:

  • Selective photosensitivity (lD <= 70 nm);
  •  Determination of  X and Y coordinates of received optic signals by linear characteristic, the slope of the coordinate characteristic  – 6×103 V/W×mm;
  •  Detection of unitary optic signals with an impulse duration less than 10 ns and of more than 1 GHz.

Areas of Application:
Instrument engineering, Electronics, Military. Control and direction of moving objects.

Stage of Development:
The quadrant-photodiode was tested at:

  • National Research and Development Institute for Laser, Plasma and Radiation, Bucharest, Romania;
  • Régie Autonome « Industrial Army Group », Romania

Covered by the patent of R. Moldova MD 887 G2

Topology of quadrant-photodiode
Fig.1. Topology of quadrant-photodiode: 1 - four sectors for determination position of light signal, 2 - circumferential guard ring, 3- central detector.

Coordinates characteristics for various radius of the central detector
Fig.2 Coordinates characteristics for various radius of the central detector.

Contact Details:
Technical University of Moldova
Contact persons:
Valerian DOROGAN, vice-rector
Sergiu ZAPOROJAN, department of scientific investigations
Republic of Moldova, Chisinau, 168, Stefan cel Mare Ave.
+ (373 22) 23 54 37,
+ (373 22) 23 54 05