Margarita A Man'ko

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.

Microdisplacement and microvibration sensors based on semiconductor lasers

ConclusionThe above analysis of a microvibration sensor based on a semiconductor laser has shown that in the optimal operating regime one can expect a detection ability of ∼10−2 nm.It is preferable to record an optical signal (change of radiation power) than an optoelectronic one (change diode voltage).Several sensor variants were constructed: with an ILPN-202 commercial laser diode, with a laser cartridge, and with the LMF-1300 single-mode laser module. Since real sensors contain additional noise sources (pumping- and recording-system noise, fluctuations due to parasitic reflection, etc.), the sensitivity limit could not be reached. The detection ability ranges, depending on the scheme employed, from fraction of a nanometer to several nanometers, but is perfectly acceptable for many practical applications.

Single-mode transmitting modules for fiber-optics lines operating at wavelengths 1.3 and 1.55 μm

Optoelectronic sources for the 1.3- and 1.55-μm bands have been developed on the basis of InGaAsP/InP heterostructures in the form of modules that include a Peltier microcooler, a temperature sensor, and a photodiode monitor. The properties of single-mode sources are presented and the technique of is discribed of coupling them to single-mode fibers using a taper and a microlens lightguide pigtail. Data on the influence of parasitic and some results on high-frequency modulation and information transmission are given.