Provided is a method for producing a wavelength conversion sintered body that emits light under irradiation of excitation light. The method for producing a wavelength conversion sintered body includes: preparing a molded body obtained by molding a mixture containing an -SiAlON fluorescent material and aluminum oxide particles and having a content of Ga of 15 ppm by mass or less; and primary calcining the molded body at a temperature in a range of 1,370 C. or more and 1,600 C. or less to obtain a first sintered body.

A light emitting device includes a semiconductor light source device including a plurality of semiconductor light emitting elements, a wavelength conversion member that converts a wavelength of irradiation light from the semiconductor light source device, a concentrating lens that concentrates the irradiation light from the semiconductor light source device, and a cylindrical holder. The semiconductor light source device, the wavelength conversion member and the concentrating lens is supported by a support portion provided in an inner diameter portion of the cylindrical holder.

A wavelength conversion device for laser light including a laser light source that emits laser light having a predetermined wavelength; a first substrate that is light-transmissive; a second substrate that is light-transmissive; a phosphor layer provided between and in surface contact with the first substrate and the second substrate, the phosphor layer converting a wavelength of the laser light; and a gap-maintaining component located between the first substrate and the second substrate, the gap-maintaining component adjusting a thickness of the phosphor layer by maintaining a uniform distance between the first substrate and the second substrate. Each of the first substrate and the second substrate has a thermal conductivity higher than a thermal conductivity of the phosphor layer. The gap-maintaining component is a plurality of thickness adjustment particles that are light-transmissive and have a shape having a substantially equal diameter, and the shape is one of wire-shaped, ring-shaped, and protruding.

A wavelength conversion device, etc., for laser light according to the present disclosure includes: a first substrate that is light-transmissive; a second substrate that is light-transmissive; and a phosphor layer provided between the first substrate and the second substrate and including a phosphor that converts the wavelength of incident laser light having a predetermined wavelength. The laser light has a laser irradiation power density of at least 0.03 W/mm.sup.2, and each of the first substrate and the second substrate has a thermal conductivity higher than the thermal conductivity of the phosphor layer.

A wavelength converting apparatus includes a moving device including a crystal holder holding a nonlinear crystal for converting a wavelength of laser light incident thereon and outputting the laser light, and a driving unit including a voice coil motor and moving the holder at least in a direction orthogonal to a first direction that is an optical path axis direction of the laser light. The driving unit turns the holder to change an incident angle of the laser light on the crystal. The driving unit includes: a two-dimensional driving unit including a planar voice coil motor, and a one-dimensional driving unit including a cylindrical voice coil motor. The two-dimensional driving unit performs linear driving in a second direction orthogonal to the first direction, and rotary driving around a third direction orthogonal to the first and second directions. The one-dimensional driving unit performs linear driving in the third direction.

A converter for an optoelectronic component, an optoelectronic component, a method for forming a converter for an optoelectronic component and a material for a reflector of an optoelectronic component are disclosed. In an embodiment, a converter includes a conversion element for converting a wavelength of electromagnetic radiation which passes through at least a part of the conversion element and a reflector, wherein the reflector includes a reflector material which includes MgF.sub.2 and/or an inorganic material as a matrix material in which a plurality of particles is embedded, wherein a refractive index of the matrix material amounts to at least 1 and at most 2, and wherein a refractive index of the particles amounts to at least 1.5.

A converter for an optoelectronic component, an optoelectronic component, a method for forming a converter for an optoelectronic component and a material for a reflector of an optoelectronic component are disclosed. In an embodiment, a converter includes a conversion element for converting a wavelength of electromagnetic radiation which passes through at least a part of the conversion element and a reflector, wherein the reflector includes a reflector material which includes MgF.sub.2 and/or an inorganic material as a matrix material in which a plurality of particles is embedded, wherein a refractive index of the matrix material amounts to at least 1 and at most 2, and wherein a refractive index of the particles amounts to at least 1.5.

In a DBR laser of a wavelength-tunable transmitter, a rear DBR region, an active region, and a front DBR region are integrated along an optical axis direction. The diffraction grating structure is set so that an oscillation mode using a reflection peak on the shortest wavelength side among a plurality of reflection peaks corresponding to the wavelength-tunable band is easily oscillated the most in a state where a current to the two DBR regions of the SSG-BPFR is 0. The SSG-DBR laser is configured such that the average period value of the diffraction grating of the front DBR is larger than the average period value of the diffraction grating of the rear DBR. The diffraction grating is configured so that the wavelengths of the reflection peaks on the shortest wavelength side among the plurality of reflection peaks coincide with each other between the two DBR regions in a state where no current is supplied.

A light-emitting device includes a semiconductor laser element, a wavelength conversion member, and a package. The wavelength conversion member includes a wavelength conversion portion and a reflective portion as in the specification. The wavelength conversion portion includes a light incident surface and a light-emitting surface as in the specification. The package includes a disposition region as in the specification. The wavelength conversion member is disposed at a position away in a first direction from a position at which the semiconductor laser element is disposed. In a plan view perpendicular to the light-emitting surface, the light-emitting surface has a shape that has a first region as in the specification, and a region of at least 80% or more of the light incident surface overlaps an imaginary line that passes through a point of the light-emitting surface closest to the semiconductor laser element and that is parallel to the second direction.

A wavelength conversion device and a light source system, including: a substrate; a first light-emitting portion disposed on the substrate, wherein the first light-emitting portion includes a first light guide area and a counterweight area provided on the same layer as the first light guide area, the first light guide area being used for guiding first light, and the counterweight area being used for making the weight distribution of the wavelength conversion device substantially uniform; and a second light-emitting portion provided on the substrate on the same side as the first light-emitting portion, the second light-emitting portion including a conversion area, and the conversion area being used to convert at least a part of excitation light into excited light for emission when the excitation light is received.