An integrating sphere is an optical device for various purposes such as measuring the optical Flux from a Laser diode, light-emitting Diode (LED) or bulb, or measuring Scattering losses from a surface. It is a hollow sphere with a diffusely reflecting internal surface, typically two or more small openings (ports) for introducing Light or attaching a photodetector, and often some so-called baffles, which are light barriers used to prevent direct illumination of a Detector by a light source. The arrangement causes many diffuse reflections of the introduced light before it reaches a detector, SO that the light flux becomes very uniform at the detector, and nearly independent of the spatial and Polarization properties of the introduced light: the detected Optical Power depends basically only on the total introduced power.