Abstract: A semiconductor light emitting element includes an optical waveguide having a first and second waveguide provided with a width that allows propagation of light in a second-order mode or higher and a multimode optical interference waveguide provided with a wider width than the first and second waveguide and arranged at a position therebetween. The semiconductor light emitting element further includes a first optical loss layer facing the first waveguide in an active-layer crossing direction for causing a loss of light that is propagating in the first waveguide in the second-order mode or higher and a second optical loss layer facing the second waveguide in an active-layer crossing direction for causing a loss of light that is propagating in the second waveguide in the second-order mode or higher, the active-layer crossing direction being orthogonal to a surface of an active layer.

Abstract: A semiconductor light emitting element includes an optical waveguide having a first and second waveguide provided with a width that allows propagation of light in a second-order mode or higher and a multimode optical interference waveguide provided with a wider width than the first and second waveguide and arranged at a position therebetween. The semiconductor light emitting element further includes a first optical loss layer facing the first waveguide in an active-layer crossing direction for causing a loss of light that is propagating in the first waveguide in the second-order mode or higher and a second optical loss layer facing the second waveguide in an active-layer crossing direction for causing a loss of light that is propagating in the second waveguide in the second-order mode or higher, the active-layer crossing direction being orthogonal to a surface of an active layer.

Abstract: Provided is an optical mode switch that can effect a more compact optical switch. The optical mode switch (100) is provided with: a single input port (1); a single output port (2); two waveguides (10) provided in parallel between the input port (1) and the output port (2); and a refractive index altering means (8) that alters the refractive index of the waveguides. Any given mode light input to the input port (1) is output as any given mode light from the output port (2) in accordance with the refractive index altered by the refractive index altering means (8).

Abstract: Provided is an optical mode switch that can effect a more compact optical switch. The optical mode switch (100) is provided with: a single input port (1); a single output port (2); two waveguides (10) provided in parallel between the input port (1) and the output port (2); and a refractive index altering means (8) that alters the refractive index of the waveguides. Any given mode light input to the input port (1) is output as any given mode light from the output port (2) in accordance with the refractive index altered by the refractive index altering means (8).

Abstract: A semiconductor laser is provided with one or more rear ports and one front port and with a multi-mode interference optical waveguide that has an active layer (light emitting layer) in all regions in plan view. The front port corresponds to an imaging point at which fundamental mode light forms an image in the active layer (light emitting layer) perpendicular to the waveguide direction of the multi-mode interference optical waveguide, and in plan view the front port is disposed along a central line, off center with respect to a central line, along the waveguide direction of the multi-mode interference optical waveguide.

Abstract: An analyzing element (10) is provided with a sample chamber (11) into which a gas or liquid sample is introduced; detection light waveguides (12a, 12b) arranged adjacent to the sample chamber (11) for guiding detection light for detecting a sample; and a detection light inputting section (13) for inputting the detection light, which is traveling in a direction along the detection light waveguides (12a, 12b), into the detection light waveguides (12a, 12b) from the end surface of the detection light waveguides (12a, 12b). The detection light waveguides (12a, 12b) have an exposed surface (14) exposed in the sample chamber (11).

Abstract: A bistable element (100) comprising: a multi-mode interference optical waveguide (1), has two ports on one edge face (1a) thereof, and has one port on the other edge face (1b) thereof; a first group of optical waveguides (2), and each of which is composed of two optical waveguides each having one edge face connected to each port arranged on the one edge face (1a) side of the multi-mode interference optical waveguide (1); and a second group of optical waveguides (3), and each of which is composed of one optical waveguide having one edge face connected to each port arranged on the other edge face (1b) side of the multi-mode interference optical waveguide (1). The multi-mode interference optical waveguide (1) has a saturable absorption region (22) where the absorption coefficient is reduced to cause the saturation of the amount of absorbed light when the intensity of incident light becomes high.

Abstract: A semiconductor laser is provided with one or more rear ports and one front port and with a multi-mode interference optical waveguide that has an active layer (light emitting layer) in all regions in plan view. The front port corresponds to an imaging point at which fundamental mode light forms an image in the active layer (light emitting layer) perpendicular to the waveguide direction of the multi-mode interference optical waveguide, and in plan view the front port is disposed along a central line, off center with respect to a central line, along the waveguide direction of the multi-mode interference optical waveguide.

Abstract: A bistable element (100) comprising: a multi-mode interference optical waveguide (1), has two ports on one edge face (1a) thereof, and has one port on the other edge face (1b) thereof; a first group of optical waveguides (2), and each of which is composed of two optical waveguides each having one edge face connected to each port arranged on the one edge face (1a) side of the multi-mode interference optical waveguide (1); and a second group of optical waveguides (3), and each of which is composed of one optical waveguide having one edge face connected to each port arranged on the other edge face (1b) side of the multi-mode interference optical waveguide (1). The multi-mode interference optical waveguide (1) has a saturable absorption region (22) where the absorption coefficient is reduced to cause the saturation of the amount of absorbed light when the intensity of incident light becomes high.

Abstract: To provide a super luminescent light emitting diode comprising an optical waveguide structure which supplies particularly-high optical output. The super-luminescent light emitting diode includes: a first optical waveguide, of which one end is optically connected to one end of a multimode interference optical waveguide, and of which the other end forms a first light emitting edge; and a second optical waveguide, of which one end is optically connected to the other end of the multimode interference optical waveguide, and of which the other end forms a second light emitting edge. Each of the first and second optical waveguides has a width smaller than the width of the multimode interference optical waveguide.

Abstract: To provide a super luminescent light emitting diode comprising an optical waveguide structure which supplies particularly-high optical output. The super-luminescent light emitting diode includes: a first optical waveguide, of which one end is optically connected to one end of a multimode interference optical waveguide, and of which the other end forms a first light emitting edge; and a second optical waveguide, of which one end is optically connected to the other end of the multimode interference optical waveguide, and of which the other end forms a second light emitting edge. Each of the first and second optical waveguides has a width smaller than the width of the multimode interference optical waveguide.

Abstract: An analyzing element (10) is provided with a sample chamber (11) into which a gas or liquid sample is introduced; detection light waveguides (12a, 12b) arranged adjacent to the sample chamber (11) for guiding detection light for detecting a sample; and a detection light inputting section (13) for inputting the detection light, which is traveling in a direction along the detection light waveguides (12a, 12b), into the detection light waveguides (12a, 12b) from the end surface of the detection light waveguides (12a, 12b). The detection light waveguides (12a, 12b) have an exposed surface (14) exposed in the sample chamber (11).

Abstract: To provide a semiconductor laser diode and a semiconductor optical amplifier and an optical communication device incorporating the semiconductor laser diode or the semiconductor optical amplifier which enable low power consumption and high optical output. A semiconductor laser diode according to an embodiment of the present invention is a semiconductor laser diode 100 comprised of an active waveguide, the active waveguide including a first waveguide 11a that supplies a plurality of modes including a fundamental mode; and a second waveguide 12a that is wider than the first waveguide 11a and supplies a multimode, wherein the fundamental mode is provided as an oscillation light oscillated from the active waveguide.

Abstract: To provide a semiconductor laser diode and a semiconductor optical amplifier and an optical communication device incorporating the semiconductor laser diode or the semiconductor optical amplifier which enable low power consumption and high optical output. A semiconductor laser diode according to an embodiment of the present invention is a semiconductor laser diode 100 comprised of an active waveguide, the active waveguide including a first waveguide 11a that supplies a plurality of modes including a fundamental mode; and a second waveguide 12a that is wider than the first waveguide 11a and supplies a multimode, wherein the fundamental mode is provided as an oscillation light oscillated from the active waveguide.

Abstract: A laser diode with a single-transverse-mode output having a laser cavity comprising both single-mode and multi-mode waveguide portions, and a method of manufacturing such a laser diode are disclosed. There are a pair of single transverse waveguide regions at opposite ends of a multi-mode waveguide. The multi-mode waveguide is a 1×1 multi-mode interference waveguide, with a wider width than the single-mode portions. Use of the multi-mode region improves the power output, threshold current density, and overall efficiency in comparison to a similarly constructed laser diode in which the entire laser cavity is single-mode.

Abstract: A semiconductor optical amplifier includes (a) a single-mode waveguide region which provides a single-mode to a guided light-wave, (b) a first multi-mode interference waveguide region which has a greater waveguide width than that of the single-mode waveguide region, is optically connected to the single-mode waveguide region, and provides a mode including a multi-mode, to the guided light-wave, and (c) a second multi-mode interference waveguide region which has a greater waveguide width than that of the first multi-mode interference waveguide region, is optically connected to the first multi-mode interference waveguide region, and provides a mode including a multi-mode, to the guided light-wave.

Abstract: A semiconductor laser capable of realizing a regular single mode output and achieving a high gain and high output as well as improving the COD level and the spatial hole burning and not causing a mode conversion loss in principle is provided. The semiconductor laser has a single mode waveguide and a multi-mode waveguide. The multi-mode waveguide has a wider width than that of the single mode waveguide. The single mode waveguide provides a single mode to an oscillated light oscillated from an active light waveguide. While the multi-mode waveguide provides modes including a multi-mode to the oscillated light, the resulting output mode emits into regular single mode output because of the self-imaging effect of multimode interference. Further more, the semiconductor laser has a light output end constituted by an end of the multi-mode waveguide.

Abstract: A laser diode of the present invention comprises a light waveguide. The light waveguide includes a multi-mode waveguide region.

Abstract: A semiconductor waveguide photodetector having a high receiving efficiency has single mode light transmitted as the incident light signal. The semiconductor waveguide photodetector includes a 1×1 multi mode interference (MMI) light waveguide region, and two single mode waveguide regions, each of which is connected at an end to the multi mode region. The length of the multi mode waveguide region is about 100 &mgr;m and the lengths of the single mode waveguide region are about 10 &mgr;m. The width of multimode waveguide region is 6 &mgr;m and those of single mode waveguide regions are 1.5 &mgr;m. The semiconductor waveguide photodetector detects and filters the incident light in the same material within the multiple mode region.

Abstract: In a semiconductor laser diode module, a semiconductor laser diode including a multi-mode interference type active waveguide is provided.