Analysis of photodetection regime in injection laser amplifiers

A theory is derived for the effect of external radiation on the voltage across a laser diode in the amplification regime. A correlation is noted between the theoretical and experimental results on the behavior of the electrical signal as a function of the current through the diode. The photosensitivity spectra are calculated without regeneration. The width of these spectra is shown to be about 10 meV for AlGaAs amplifiers. The effect of the resonator on the photosensitivity spectrum of an injection amplifier is studied. Superselective photodetection is possible.