NOVELTY - The system has a solar optical waveguide (SOW) including a waveguide body comprising a front top radiation injection port (0305), a front face radiation input port (0306) and a rear face radiation output port (0307). The front top radiation injection port collects incident radiant solar energy from a solar radiation source. The body comprises optically reflective surfaces exclusive of the radiation output port. The optically reflective surfaces direct solar energy from the front top radiation injection port and the front face radiation input port to the output port.    USE - Modular solar collector system (MSCS) for use in an exterior structure e.g. roadway, building roof/exterior wall and water tower, to supply solar energy to a solar water purification system, a solar water heating system and a passive building lighting system. Can also be used for a local residence and a business.    ADVANTAGE - The system is cost effective and easily manufactured, and has low profile. The system can be oriented horizontally and vertically at other angles with respect to a ground plane, and does not require mechanized placement for sun tracking. The system is modular, extensible and durable, and can be expanded in linear vectors and in planar arrays. The system anticipates modular water heating and purification systems that are local to a building or structure and permits the structure to operate semi-independently from an electrical grid, thus reducing or eliminating need for electricity from the electrical grid.    DETAILED DESCRIPTION - The waveguide body is made of material selected from a group consisting of glass, low lead glass, borosilicate glass, crown glass, quartz glass, clear plastic, acrylic plastic, polycarbonate plastic, polymethyl methacrylate plastic and allyl diglycol carbonate (ADC) plastic. An INDEPENDENT CLAIM is also included for a modular solar collector method.    DESCRIPTION OF DRAWING(S) - The drawing shows a side sectional view of reflective surfaces within interior of a solar/optical radiation waveguide body.    Front top radiation injection port (0305)    Front face injection radiation input port (0306)    Rear face radiation output port (0307)    Transmissive/reflective surfaces (0800)    Solar/optical radiation waveguide structure (0801)    Solar radiation source (0811)    Pass-thru radiation source (0812)    Solar radiation sink (0813)