Power-by-light systems and their components: an evaluation.

This paper describes the testing of small sized systems and their components that use power-by-light (PBL) to transfer energy across a barrier. The PBL systems used improved high power laser diodes, large numerical aperture fibers, improved high efficient, high power solar cells, and low input-to-high output voltage dc-dc converters. The laser diodes emitted up to 3.6 W continuously by converting approximately 40% of its electrical power to light power into fibers that transmitted up to 92% of its incident energy flux. The specially fabricated solar cell converted 46% of its incident light power to electrical power at a fill factor of 89%. The most efficient 100- and 220-mJ PBL systems charged capacitors in 0.64 and 0.8 s for a total system efficiency of 3.4 and 5.5%. Expected improvements could yield system efficiencies of 12%.

Coupling of high power laser diode optical power.

This paper describes the characteristics of optical couplers with high power laser diodes as sources. The couplers investigated include gradient-index (GRIN) lenses manufactured by Nippon Sheet Glass, a plano-convex lens, a prism, optical fibers manufactured by Ensign-Bickford and Nippon Sheet Glass, and fiber optic stub manufacture by Spec Tran. The characteristics measured included: (1) GRIN lens transmission of up to 97%, fiber transmission of up to 90%, plano-convex lens transmission of up to 92%; (2) intensity distribution contours and profiles of the beam transmitted through GRIN lenses and optical fibers; (3) the beam dimensions of a collimating system; and (4) the divergence of optical fibers of varying lengths. Spectra Diode Laboratory and McDonnell Astronautics Company/Opto Electronics Center manufactured the laser diodes sources that emitted up to 3.6 W.