A lighting system includes a helical light-transmitting fiber and a light source. The helical light-transmitting fiber is doped with a first wavelength converting material and defines a helical axis. The light source is aligned axially with the helical fiber such that a portion of any light emitted by the light source will pass through the open space between the turns of the first helical fiber and a portion of any light emitted by the light source will be received by the helical fiber and converted to light of a predetermined color. Adjustment of the compression of the helical fiber will adjust the mixture of light emitted by the system. The helical fiber may bias an illuminated button bulb upward in a housing, such that depressing the button bulb changes the color of the light that illuminates the button bulb.