A Ga0.51In0.49P/GaAs-based photovoltaic converter for two-directional optical power and data transmission

A GaAs-based photovoltaic converter for optical-to-electrical power conversion and for data transmission was developed. the device structure is based on a modified GaAs solar cell structure having a lattice-matched Ga_0.51In_0.49P window layer. the converter consists of an array of series-connected photovoltaic cells. the input optical laser power is transmitted via a single optical multimode fibre and distributed homogeneously to the separate cells. One of the cells has separate connections for acting as a light-emitting diode for data transmission in the opposite direction. the conversion eficiency of the individual cells was measured to be 49%, and the array conversion efficiency was 41%.     

On some decidability problems for HDOL systems with nonsingular Parikh matrices

The problem of decidability of ultimate equivalence, emptiness of intersection and finiteness of intersection for HD0L sequences the generating morphisms of which have nonsingular Parikh matrices is investigated. The first and the third of these decidability problems are shown to be closely connected with the equivalence problem for these sequences. In certain special cases the problems are proved to be solvable. A connection between the problem of effective findability of zeros in Z-rational sequences and the above problems is established (cf. [10]).