Light-emitting device and optical fiber

A light-emitting device comprising:

• an optical fiber including a light incident portion, a light emerging portion, and a wavelength converting portion, the wavelength converting portion being provided between the light incident portion and the light emerging portion and containing a wavelength converting material, the wavelength converting material being configured to be excited by excitation light to produce a spontaneous emission of light having a longer wavelength than the excitation light, the wavelength converting material being configured to amplify the spontaneous emission of light to produce an amplified spontaneous emission of light;
• a first light source unit being configured to emit the excitation light to the light incident portion;
• and
• a second light source unit being configured to emit seed light to the light incident portion, the seed light being light for causing a stimulated emission of light to be produced from the wavelength converting material that has been excited by either the excitation light or the amplified spontaneous emission of light, wherein:
• the seed light is formed by a plurality of seed light rays, having mutually different wavelengths and the plurality of seed light rays are incident on the light incident portion, and
• the first light source unit and the second light source unit each include:
• a white light source;
• and
• a spectroscopic grating configured to allow the excitation light and the plurality of seed light rays to emerge from the spectroscopic grating by separating light emitted from the white light source into multiple components of the light.

An optical fiber comprising:

• a light incident portion;
• a light emerging portion;
• and
• a wavelength converting portion provided between the light incident portion and the light emerging portion and containing a wavelength converting material, the wavelength converting material being configured to be excited by excitation light to produce a spontaneous emission of light having a longer wavelength than the excitation light, the wavelength converting material being configured to amplify the spontaneous emission of light to produce an amplified spontaneous emission of light, wherein:
• the wavelength converting material is configured such that seed light incident on the light incident portion causes a stimulated emission of light from the wavelength converting material that has been excited by either the excitation light or the amplified spontaneous emission of light,
• the seed light is formed by a plurality of seed light rays having mutually different wavelengths and the plurality of seed light rays are incident on the light incident portion, and
• the wavelength converting material contains Pr3+ and Tb3+.