Side-emitting LEDs are proposed showing a wide optical spectrum. The LEDs were fabricated using a special growth technique called shadow masked growth (SMG). The width of the window in the shadow mask was gradually changed along the LED stripe direction and therefore resulted in a continuous variation of the layer thickness. The combination with a quantum well active region results in a continuous variation in bandgap and emission wavelength. These different spectra add up at one side of the LED offering a broad spectrum. By decreasing the width of the window, starting from 100 μm, GaAs/AIGaAs GRINSCH SQW LEDs have been realised with spectral widths up to 63 nm and very small spectral ripple.