Electrical diagnostics of the amplifier operation and a feasibility of signal registration on the basis of the voltage saturation effect in junction laser diodes

Investigations have been carried out on the electrical voltage changing in the laser diode in the prethreshold amplification regime with respect to the input optical signal at wavelengths near the intrinsic lasing wavelengths. The inversion threshold, the running-wave and resonant amplification regimes, and the lasing threshold can be identified by the electrical signal in the diode. The signal changes polarity with the growth of pump current being positive in the photodiode operation and negative in the amplifier regime. The amplitude of the negative signal is ∼ 1 mV. The feasibility of using the saturation effect in the injection lasers has been studied for a signal transmission through the optical fiber coupled to AlGaAs stripe DH lasers as both terminals.