Abstract: Disclosed are a method and device for measuring the resistance of a light-emitting diode that can measure the resistance value of the light-emitting diode accurately in a non-destructive manner. The disclosed method may include: measuring a first radiative current component of an injected current for the light-emitting diode by using the internal quantum efficiency of the light-emitting diode; generating a second radiative current component by modeling the first radiative current component; and computing a resistance value of the light-emitting diode by using the first and second radiative current components resulting from an applied voltage to the light-emitting diode.

Abstract: Disclosed are a method and device for measuring the resistance of a light-emitting diode that can measure the resistance value of the light-emitting diode accurately in a non-destructive manner. The disclosed method may include: measuring a first radiative current component of an injected current for the light-emitting diode by using the internal quantum efficiency of the light-emitting diode; generating a second radiative current component by modeling the first radiative current component; and computing a resistance value of the light-emitting diode by using the first and second radiative current components resulting from an applied voltage to the light-emitting diode.

Abstract: A method for measuring the efficiency of an optical element is disclosed.

Abstract: Disclosed is a light emitting device including a first conductive type semiconductor layer; a second conductive type semiconductor layer disposed on the first conductive type semiconductor layer; and an active layer disposed between the first conductive type semiconductor layer and the second conductive type semiconductor layer, the active layer comprising quantum well layers and quantum barrier layers, wherein each of the quantum well barrier layers comprises first barrier layers and a second barrier layer disposed between the first barrier layers, and an energy bandgaps of the second barrier layer is larger than energy bandgaps of the quantum well layers and smaller than energy bandgaps of the first barrier layers.

Abstract: A method for measuring the efficiency of an optical element is disclosed.

Abstract: A light emitting diode includes a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on a substrate, and a first electrode connected to the first semiconductor layer. The first electrode includes an edge electrode including first and second edge portions opposite to each other, and a line electrode including first and second line portions respectively extending from the first and second edge portions. The edge electrode has a closed loop-shape. A distance between the first line portion and the second edge portion is equal to or less than a quarter of a length of the first line portion. A distance between the second line portion and the first edge portion is equal to or less than a quarter of a length of the second line portion.

Abstract: A light emitting diode includes a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on a substrate, and a first electrode connected to the first semiconductor layer. The first electrode includes an edge electrode including first and second edge portions opposite to each other, and a line electrode including first and second line portions respectively extending from the first and second edge portions. The edge electrode has a closed loop-shape. A distance between the first line portion and the second edge portion is equal to or less than a quarter of a length of the first line portion. A distance between the second line portion and the first edge portion is equal to or less than a quarter of a length of the second line portion.

Abstract: Provided is a method and apparatus for measuring efficiency of an optical device. In the method, a power of emission light from the optical device is calculated by irradiating an excitation stimulus on the optical device. A power of a reference excitation stimulus at which a variation of recombination coefficients in a quantum well of the optical device with respect to a variation of carrier concentration in the quantum well of the optical device becomes minimum is extracted. An internal quantum efficiency of the optical device at the power of the reference excitation stimulus is calculated. An internal quantum efficiency of the optical device at powers of various excitation stimuli is calculated from the internal quantum efficiency of the optical device at the power of the reference excitation stimulus.

Abstract: Disclosed is a light emitting device including a first conductive type semiconductor layer; a second conductive type semiconductor layer disposed on the first conductive type semiconductor layer; and an active layer disposed between the first conductive type semiconductor layer and the second conductive type semiconductor layer, the active layer comprising quantum well layers and quantum barrier layers, wherein each of the quantum well barrier layers comprises first barrier layers and a second barrier layer disposed between the first barrier layers, and an energy bandgaps of the second barrier layer is larger than energy bandgaps of the quantum well layers and smaller than energy bandgaps of the first barrier layers.

Abstract: Provided is a method and apparatus for measuring efficiency of an optical device. In the method, a power of emission light from the optical device is calculated by irradiating an excitation stimulus on the optical device. A power of a reference excitation stimulus at which a variation of recombination coefficients in a quantum well of the optical device with respect to a variation of carrier concentration in the quantum well of the optical device becomes minimum is extracted. An internal quantum efficiency of the optical device at the power of the reference excitation stimulus is calculated. An internal quantum efficiency of the optical device at powers of various excitation stimuli is calculated from the internal quantum efficiency of the optical device at the power of the reference excitation stimulus.

Abstract: A semiconductor laser diode including a substrate, and a first semiconductor layer, an active layer, a second semiconductor layer and an electrode sequentially formed on the substrate is provided. In the semiconductor laser diode, the second semiconductor layer has a ridge and the electrode is formed on the ridge of the second semiconductor layer at a width which is less than the width of the ridge.

Abstract: Disclosed is an optical semiconductor device that provides an optical gain or optical loss depending on application of electric current. The optical semiconductor device comprises: a lower clad layer; an active layer disposed on the lower clad layer, the active layer generating optical gain or optical loss depending on injection of carriers; an upper clad layer disposed on the active layer, the upper clad layer serving to trap light in the active layer in cooperation with the lower clad layer; and a temperature control part for controlling the temperature distribution of the active layer along the light propagation axis in such a manner that temperature of the active layer varies depending on positions in the active layer.

Abstract: Disclosed is a laser module for generating laser light without a wavelength shift during a direct modulation of high frequency. The laser module includes: a laser light source for generating a first light; a nonlinear crystal for secondary harmonic generation for wavelength-converting the first light into a second light; and a multi-mode interferometer placed between the laser light source and the secondary harmonic generation, for modulating the intensity of the first light.

Abstract: A semiconductor laser diode including a substrate, and a first semiconductor layer, an active layer, a second semiconductor layer and an electrode sequentially formed on the substrate is provided. In the semiconductor laser diode, the second semiconductor layer has a ridge and the electrode is formed on the ridge of the second semiconductor layer at a width which is less than the width of the ridge.

Abstract: Disclosed is an optical semiconductor device that provides an optical gain or optical loss depending on application of electric current. The optical semiconductor device comprises: a lower clad layer; an active layer disposed on the lower clad layer, the active layer generating optical gain or optical loss depending on injection of carriers; an upper clad layer disposed on the active layer, the upper clad layer serving to trap light in the active layer in cooperation with the lower clad layer; and a temperature control part for controlling the temperature distribution of the active layer along the light propagation axis in such a manner that temperature of the active layer varies depending on positions in the active layer.

Abstract: A semiconductor laser diode and a method of fabricating the same are provided. The semiconductor laser diode includes: a substrate; a predetermined compound semiconductor layer formed on the substrate; a lower cladding layer formed on the compound semiconductor layer; an active layer formed on the lower cladding layer; an upper cladding layer formed on the active layer and having a ridge formed in the middle thereof; trenches formed to a predetermined depth on at least one side of the ridge to penetrate the active layer from the upper cladding layer; a current blocking layer formed on surfaces of the upper cladding layer, except a top surface of the ridge, and inner walls of the trenches; a contact layer formed on the top surface of the ridge; and a first electrode formed on top surfaces of the contact layer and the current blocking layer.

Abstract: A distributed feedback semiconductor laser and a method of manufacture includes first and second clad layers having predetermined refractive indexes that are formed on a semiconductor substrate. A guide layer propagates light between the first and second clad layers. An oscillating clad layer oscillates light at a predetermined wavelength and an amplifying clad layer amplifies the light with a predetermined gain between the first clad layer and the guide layer. The distributed feedback semiconductor laser is divided into a laser oscillation section including the oscillating clad layer and a laser amplification section including the amplifying active layer. First and second gratings are formed on the lower surface of the guide layer in the laser oscillation section and in the laser amplification section, respectively.

Abstract: A distributed feedback semiconductor laser and a method of manufacture includes first and second clad layers having predetermined refractive indexes that are formed on a semiconductor substrate. A guide layer propagates light between the first and second clad layers. An oscillating clad layer oscillates light at a predetermined wavelength and an amplifying clad layer amplifies the light with a predetermined gain between the first clad layer and the guide layer. The distributed feedback semiconductor laser is divided into a laser oscillation section including the oscillating clad layer and a laser amplification section including the amplifying active layer. First and second gratings are formed on the lower surface of the guide layer in the laser oscillation section and in the laser amplification section, respectively.

Abstract: Disclosed is a polarization insensitive semiconductor optical amplifier (SOA) in an optical amplifying element having a substrate and a multi-layer structure, crystal growth layer including an active layer formed on the substrate. In the inventive optical amplifier, the active layer is divided into first and second areas having different polarization modes. An electrode means independently applies currents to the first and second areas. Therefore, the polarization insensitive semiconductor optical amplifier is capable of separately controlling TE and TM polarization gains so as to approximately equalize the TE polarization gain to the TM polarization gain.

Abstract: A distributed feedback semiconductor laser device having a semiconductor substrate, a bottom electrode formed on a bottom surface of the substrate, a corrugation-shaped grating formed on a top surface of the substrate, an active waveguide layer whose energy band gap profile and whose light propagation constant are varied along cavity length direction of the laser device, the active waveguide layer being formed over the corrugation-shaped grating, a clad layer formed to cover the active waveguide layer, and a top electrode formed on a top of the clad layer. The active waveguide layer is grown by a selective metal organic vapor phase epitaxy with use of slender insulation masks having a variation in width, the slender insulation masks being arranged at both sides of an area on which the active waveguide layer is grown.