Projection system

A projection system, comprising:

• a light source unit;
• a spatial light modulation unit configured to control emission light emitted from the light source unit to form an optical image;
• and
• a projection optical system configured to project the optical image formed by the spatial light modulation unit,
• the light source unit including:
• an optical fiber including a light incident portion, a light emerging portion and a wavelength-converting portion, the wavelength-converting portion being disposed between the light incident portion and the light emerging portion, and the wavelength-converting portion including wavelength-converting elements that are able to be excited by excitation light to produce spontaneous emission of light having a longer wavelength than the excitation light, and also excited by amplified spontaneous emission of light;
• a first light source part configured to make the excitation light incident on the light incident portion;
• and
• a second light source part configured to make seed light incident on the light incident portion, the seed light causing the wavelength-converting elements excited by the excitation light or the amplified spontaneous emission of light to produce stimulated emission of light.