A modular solar concentrator having an aspherical primary reflector that is a segment of a paraboloid parent shape. The peripheral shape of the segment is selected to allow arrangement of an array of concentrators in a closely-fitting pattern. The peripheral shape may be rectilinear or trapezoidal. The primary reflector may be an off-axis segment having an optical axis at or near a peripheral edge. In one embodiment, the modular solar concentrator includes a primary mirror and a secondary minor. In an alternative embodiment, the modular solar concentrator is monolithic having internal surfaces that reflect light into the optical fiber. The monolithic concentrator may include a first internal surface that functions in a manner analogous to a primary mirror and a second internal surface that functions in a manner analogous to a secondary mirror. The optical fiber may be secured in the monolith by an index matching adhesive.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
 This invention was made with government support under Contract No. DE-AC05-00OR22725 awarded by the U.S. Department of Energy. The government has certain rights in the invention.