An illumination device, comprising: a light source for generating an excitation light; a plate contains a wavelength conversion material capable of absorbing the excitation light and emitting light having wavelengths different from that of the excitation light; and an optic fiber coupler or an optic fiber bundle between the light source and the plate for transmitting the excitation light to the wavelength conversion material; wherein the light source is a laser diode or a light emitting diode, or the light source includes multiple laser diodes, multiple light emitting diodes, or both laser diodes and light emitting diodes; and wherein the optic fiber coupler or the optic fiber bundle combines excitation light generated by the light source.