Two of the most promising means of reducing the cost per kilowatt of photovoltaic (PV) systems are: 1) to reduce the cost – which includes recent progress made in CIGS; and/or 2) to increase the power – which includes progress in CPV (concentrated PV) systems. The problem in CPV is that we are also concentrating the out-of-band ultraviolet and infrared spectral components that only serve to heat the PV, causing its efficiency to plummet. Alternatively one can use optical filtering between the collection optics and the PV. Optical waveguides (including fiber) offer many useful filtering qualities and thermal distribution advantages over other optical filters. Owing to the fact that the guidance mechanism in a photonic crystal fiber (PCF) is a transverse resonance (set up by a pattern of air holes) rather that total-internal-reflection, the electric field can be predominantly confined to air instead of glass. This results in many new properties – one being minimization of Rayleigh scattering in the visible, which opens up new possibilities for solar energy applications. We demonstrate that the output power of a CIGS PV can be tripled by increasing the concentration level by a factor of 16 through the use of a PCF concentrating filter.