Polyurethane closed cell (PUCC)/SiO2 nanocomposites have been prepared by using in situ polymerization approach. The third-order optical nonlinearities of PUCC/SiO2 nanocomposites, dissolved in DMF are characterized by Z-scan technique at the measurement wavelength of 532 nm. The nonlinear refractive (NLR) indices and nonlinear absorption (NLA) coefficients of samples were calculated from close...

The modulation response, relative intensity noise (RIN) and frequency noise (FN) characteristics of quantum dot (QD) lasers are investigated theoretically in the presence of an external optical beam. Using small signal analysis of the rate equations for carriers and photons, it is demonstrated that by injecting excess carriers into the QDs excited state through optical pumping, the modulation r...

ZnO and ZnO: Mn nanocrystals synthesized via reverse micelle method. The structural properties nanocrystals were investigated by XRD and Transmission electron microscopy (TEM). The XRD results indicate that the synthesized nanocrystals had a pure wurtzite (hexagonal phase) structure. The various optical properties of these nanocrystals such as optical band gap energy, refractive index, dielectr...

In this paper, we present a high accuracy laser range finder and velocimeter using ultra-fast time-to-digital converter (TDC). The system operation is based on the measuring the round-trip time of a narrow laser pulse. A low-dark current high-speed PIN photodiode is used to detect the triggered laser beam and to produce start signal. The pulsed laser diode generates 45W optical power at 30ns du...

At first step polymer optical fibers (POFs) are used in short distance for optical data transmissions. At second step SiO2 nanoparticles were prepared by sonochemical-assisted method. Silica nanoparticles were added to polymer matrix to prepare polymer based nanocomposites. Most of the POF applications are in the medical and electrical devices. There are several methods for fabrication of POFs,...

Ultra optical glasses are proposed for attaining noble glazes of high reflection and shine. In addition, these glasses can be used as semi-mirrors and optical instruments. In this reseach attempts were devoted mainly to introduce a glass system with the highest possible refractive index in which the highest reflection is desirable. Thus different amounts of heavy metal oxides modifiers, such as...

In this paper, based on the coupled-mode and carrier rate equations, a dynamic model and numerical analysis of a multi quantum well (MQW) chirped distributed feedback semiconductor optical amplifier (DFB-SOA)  all-optical flip-flop is precisely derived. We have analyzed the effects of strains of QW and MQW and cross phase modulation (XPM) on the dynamic response, and rise and fall times of the ...