Long-wavelength laser power converters for optical fibers

Measured responsivity and illuminated I-V data are presented for III-V In/sub x/Ga/sub 1-x/As-based photovoltaic cells with bandgaps of 1.42 eV (GaAs), 0.74 (lattice-matched In/sub 0.53/Ga/sub 0.47/As), and 0.55 eV ("extended" lattice-mismatched In/sub 0.7/Ga/sub 0.3/As) relevant to their application as laser power converters (LPCs) sensitive to infrared light out to a long cutoff wavelength of 2.3 /spl mu/m. The authors present an analysis that shows the optimum LPC size to use with a Gaussian illumination profile. They compare some of the tradeoffs of more complex multijunction LPCs with simpler single-junction LPCs used with commercial DC-DC power converter chips.