Photodetectors for optical communication systems

Optical time-domain reflectometer performance and calibration studies

“…These devices are important in optical communication systems, and as a consequence have been the object of an intense development effort. Thtir characteristics have been well documented in a number of recent review articles which we will draw on in the following discussion [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Analysis of signal-to-noise ratio of the laser Doppler velocimeter

“…A photomultiplier has a rather low quantum efficiency, typically less than 10%-highest in the blue/violet part of the spectrum and lowest in the red/infra-red part -but also a very low dark current which is usually negligible for our purpose. Its main feature is the very high gain with a very low noise figure. A photodiode has a high quantum efficiency typically larger than 50% [6] -usually highest in the red/infra-red part of the spectrum-but also a relatively high dark current: typically 105 times the dark current of a photomultiplier. The gain is 1, and the noise figure is also 1 when the diode is properly biased.…”

Single photoelectron time spread measurement of fast photomultipliers

“…The investigation of time-resolution capabilities is becoming increasingly important in a multitude of research areas, such as atomic and molecular subnanosecond fluores cence decay time measurements, [3], nuclear research instrumentation [4], optical ranging experiments, [S], optical communication [6], and photon statistics experiments [7]. In this paper the time capabilities of This is particularly important in areas of experimental research where single photoelectron detection and precise subnanosecond timing are required, and where timing capa bilities of a photomultiplier are the limitation to the precision of a measurement, [8].…”