Continuous wave and Q-switched diode-pumped laser operation of Yb3+ :NaLa(MoO4)2 single crystal was demonstrated for the first time to our knowledge. A cw output power of 220 mW and slope efficiency of 46% were obtained. Q-switched laser operation was achieved with pulse duration of 60 ns. An average output power and slope efficiency were
70 mW and 22% respectively.
Technical parameters and main experimental features of laser complex for investigation of bistable phenomena in GaAs/GaAlAs interferometers and for modeling basic digital devices for optical signal processing (logical elements, switching devices, etc.) are reported.
Information-rate densities in optical communication systems are investigated on the base of the number-state model. Results of numerical simulation show that the considered characteristics increase monotonically with increasing signal power, reducing passband width and environment temperature. For quasi-monochromatic optical communication channels quantum-statistical peculiarities of information carriers can not be taken into account at large enough singal powers when fluctuation noise can be neglected.
All-optical data shift operation in a planar array based on transverse effects in optical bistability in an all-epitaxial GaAs/GaAlAs Fabry-Perot interferometer is reported. Transfer of information bit along a shift register takes about 6 ns.
Application of wavelets is investigated with ultimate time-frequency resolution for laser communications. The optimum encoding method for reaching the maximum rate of information transmission is shown to be based on WAVE-wavelets.
Dynamics of switching waves in optically bistable all- epitaxial GaAs/GaAlAs Fabry-Perot interferometers is studied experimentally. Realization of planar optical shift register based on propagation of switching waves between neighbor pixels in the plane of bistable layer is proposed.
The maximum achievable characteristics of optical communication systems with different kinds of pulse position modulation have been investigated within the framework of the number-state model. It is shown that the ultimate efficiency in optical systems with ordinary pulse position modulation is determined by the ratio of the number of photons in the signal chip to the number of chips in the signal frame. Maximum achievable efficiencies of all considered methods is compared also. The companions shows that at great values of modulation format the ultimate efficiency of pulse position modulation is higher than that of the multipulse modulation. Overlapping pulse position modulation is shown to be the most favorable one for communication channels. The application of additional encoding to such systems allows to achieve the highest power efficiency of information transmission in optical communication channels.
Principles of formation and controlled propagation of switching autowaves in optically bistable interference structures are considered. On this basis methods and devices are developed for read-in, storing, read-out, switching and transfer of information light signal sin the plane of 2D- arrays of nonlinear optical elements of micron size. A peculiarity of these methods is the possibility of shift data laterally in the array's plane in a direction that is perpendicular to the direction of incident light beams without its interim transformation into electrical signals. This distinctive feature enables developing new architecture concepts of optical information processing systems. Examples of numerical simulations and experimental realizations are presented of optical digital devices with a wide range of functional applications such as Boolean logic elements, shift registers, multiplexers/demultiplexers, basic planar ring processors, etc. The limiting operation parameters of the above devices are discussed.
We investigate some limiting characteristics of two- component optoelectronic system for information transmission on the base of number-state model and Brillouin's negentropy principle. The expression for the upper bound of the capacity of considered communication system is obtained. It is shown, that the capacity of the whole system is substantially limited by the speed characteristics of an optical subsystem. Only in the limited power range of optical signal it is determined by speed of the information transmission in an electronic subsystem. Such a consideration enables us to get deeper insight into the basic principles of information processing in channels with different nature of carriers.
A Nd:YAG Laser IntraCavity SpectroDetector (Nd:YAG LICSD) is described for sensoring small methane (CH4) concentration in the atmosphere. The concentration detectability of the Nd:YAG LICSD of about 0.003 is experimentally demonstrated and of about 1 ppm is discussed.