Abstract: A cyber shop client defines cyber shop definition information by a shop layout defining unit, an electronic shopping cart electronic form defining unit, and a goods registering unit. A cyber mall server generates cyber shop information on the basis of the cyber shop definition information from the cyber client by a shop layout registering unit, an electronic shopping cart electronic form registering unit, and a goods storing unit. Further, the cyber mall server generates display information from the cyber shop information composed of a shop management database, a shop layout database, an electronic shopping cart electronic form database, an electronic shopping care database, and a goods database by a parameter analyzing unit, a file retrieving unit, and a display data generating unit.

Abstract: A distributed feedback semiconductor laser includes a cavity extending in a cavity-axial direction. The cavity has a plurality of regions including a first region and a second region arranged along the cavity-axial direction and capable of being independently pumped. The laser further includes a plurality of waveguides with a diffraction grating and an active layer extending along the cavity-axial direction. The waveguides are formed in the regions, respectively, and coupled to each other along the cavity-axial direction. Different first and second polatization modes are defined by the coupled waveguides. The waveguides are constructed such that light intensity distributions along the cavity-axial direction in the first and second regions when pumped are different between the first and second polarization modes.

Abstract: In a semiconductor laser capable of changing its polarization mode, there are arranged a plurality of regions in its cavity direction and each region includes an active layer and a diffraction grating. The laser is driven by performing a control for switching the polarization mode to a region of the laser, out of the plurality of regions, where a refractive index is easier to be changed by a control than the other region.

Abstract: In an optical device having a diffraction grating and at least two surfaces for reflecting light, the oscillation state is switched between a first oscillation state mainly based on resonance by distributed reflection by the diffraction grating, and a second oscillation state mainly based on Fabry-Perot resonance between the two surfaces. The characteristics of one of two modes to be used are improved at the cost of coherence of the other mode.

Abstract: A diffraction grating includes first regions for mainly reflecting first polarized light and second regions for mainly reflecting second polarized light. The first regions and the second regions are alternately arranged in a light propagation direction in a variety of manners to appropriately set its polarization-mode dependency according to need. An optical semiconductor device includes a semiconductor substrate, a laser structure and that diffraction grating formed in the laser structure. The laser structure is a distributed feedback semiconductor laser structure or a distributed Bragg reflector semiconductor laser structure formed on the semiconductor substrate.

Abstract: A semiconductor laser that selectively performs oscillations in different polarization modes has first and second laser regions on a substrate. The first laser region exhibits a gain spectrum in which one polarization mode is dominant and the second laser region exhibits a gain spectrum in which a different polarization mode is dominant. Current injected independently into the each laser region causes polarization mode oscillation competition. One of the different polarization mode oscillations is selected by, for example, injecting a minute modulated current into at least one of the first and second laser regions.

Abstract: A variable wavelength light source is provided with a laser of which the oscillating state can be changed over between two oscillating states accompanied by a change of an oscillation wavelength, and an optical selection element for selecting an output light in one of the two oscillating states of the laser. The optical selection element is capable of changing over which of the output lights in the two oscillating states of the laser is to be selected. Also, by using a laser in which the oscillation wavelength in the respective oscillating states can be changed, the wavelength variation ranges in the both oscillating states can be used.

Abstract: A semiconductor quantum well structure having at least two quantum wells, each having an electron quantum level, a heavy hole quantum level and a light hole quantum level. In the two quantum wells, only their respective heavy hole quantum levels or their respective light hole quantum levels coincide with each other. Further, there is a construction in which a barrier portion between the two quantum wells has a thickness and a band gap which allow connecting the wave functions of the respective electrons between the two quantum wells. Alternatively, the thickness and band gap of the barrier allow the connection between the quantum wells of the wave functions of those holes whose quantum levels coincide with each other. In order to set the hole quantum level to a desired quantum level, a specific construction imparts an appropriate strain to the quantum wells.

Abstract: An optical semiconductor apparatus includes a single substrate, at least two semiconductor laser portions each having a semiconductor laser structure and a current injection unit for independently injecting currents into the at least two semiconductor laser portions. The semiconductor laser portions are serially arranged on the substrate in a light propagation direction and respectively includes waveguides having active layers, and layer-extending planes of the waveguides partially overlap and are not parallel to each other. The electric-field directions of TE modes in the respective semiconductor laser portions are parallel to the layer-extending planes of the waveguides, so that the non-parallel layer-extending planes of the waveguides can establish non-parallel TE modes in the respective semiconductor laser portions.

Abstract: A light source apparatus includes a light source, a mode selecting unit, a light source control unit and a mode selection control unit. An oscillation mode of the light source is switchable between a first mode under a first stimulated condition and a second mode under a second stimulated condition, and an oscillation wavelength of the light source is changeable. The mode selecting unit selects between oscillation light in the first mode and oscillation light in the second mode emitted from the light source, and the mode selecting unit can change the mode to be selected between the first mode and the second mode.

Abstract: An oscillation polarization mode selective semiconductor laser for selectively performing one of oscillations in different polarization modes, is provided. The semiconductor laser includes a substrate, a laser structure formed on the substrate, and a phase shift region formed in the laser structure. The laser structure includes an active region in which population inversion is established by a current injection thereinto. At least a portion of the phase shift region has a strained quantum well structure in which degrees of a change in refractive index for internal light in different polarization modes due to a current injection thereinto are different from each other. The polarization mode of a light output from the laser can be changed by a small amount of current injected into the phase shift region, and fluctuation in the output intensity can be suppressed during a transition operation in polarization mode.

Abstract: In a light source apparatus, the polarization mode of oscillation light from a semiconductor laser is switchable between two different polarization modes when a modulation current is injected into a portion of a light waveguide of the semiconductor laser. Light in one polarization mode and light in the other polarization mode are separately obtained from the oscillation light from the semiconductor laser. At least the light in one of the two different polarization modes is converted to an electric signal. Current injected into the semiconductor laser is controlled based on the electric signal such that a modulation state of light from the semiconductor laser is stabilized. The light in the other polarization mode, or light in one polarization mode emitted from the other emission side of the semiconductor laser may be used for optical transmission.

Abstract: In an optical apparatus, such as a semiconducter optical amplifier device and an optical filtering apparatus, there are provided an optical amplifier device, a detector and a controller. The optical amplifier device has such a structure that exhibits a both-end voltage change at an optical amplification time of an input light. The detector detects the both-end voltage change, and the controller performs a predetermined control of a portion other than the optical amplifier device, such as another optical amplifier portion and a tunable band pass filter portion.

Abstract: A strained quantum well structure comprises a substrate, and a strained quantum well. The strained quantum well has at least one well layer and a plurality of barrier layers. The well layer is sandwiched by the barrier layers. At least a portion of the well layer and the barrier layers is composed of semiconductor crystal whose amount of strain is distributed, and the band structure of the quantum well is constructed so that the transition in the quantum well layer can be exchanged between states in which first polarization-state, typically transverse electric, transition is dominant and in which second polarization-state, typically transverse magnetic, transition is dominant.

Abstract: A light-emitting apparatus capable of selecting polarization direction of a light outputted therefrom includes a semiconductor laser and an optical amplifying device. The semiconductor laser is capable of selectively changing a direction of polarization plane of the output light to one of two orthogonal directions by controlling an excited state. The optical amplifying device amplifies the output light from the semiconductor laser. The optical amplifying device has amplification factors with respect to polarized light components in two orthogonal directions.

Abstract: In an optical apparatus, such as a semiconductor optical amplifier device and an optical filtering apparatus, there are provided an optical amplifier device, a detector and a controller. The optical amplifier device has such a structure that exhibits a both-end voltage change at an optical amplification time of an input light. The detector detects the both-end voltage change, and the controller performs a predetermined control of a portion other than the optical amplifier device, such as another optical amplifier portion and a tunable band pass filler portion.

Abstract: A semiconductor optical amplifier device has an amplification factor that does not vary even if an injection current thereinto is changed. The semiconductor amplifier device includes a laser structure and an active region formed in the laser structure along a waveguide thereof. The active region is constructed so that a carrier density distribution and a light distribution in the active region cooperate to keep a resonator length of the laser structure unchanged irrespective of the change in the injection current into the laser structure.

Abstract: A semiconductor optical filter that includes a semiconductor substrate and a laser structure formed on the substrate. The laser structure includes an active layer of a quantum well structure and a grating formed along the active layer. The active layer is constructed to have a ground state level and an energy level other than the ground state level. A saturation gain of the ground state level is set to a value less than an internal loss, and the other energy level is set to permit an increase in the amount of carriers injected into the laser structure. The laser structure is typically a distributed feedback type laser structure. Anti-reflection coatings may be formed on the end surfaces of the laser structure.

Abstract: A semiconductor optical amplifying apparatus includes: a substrate; an active layer having a quantum well structure formed on the substrate, the active layer guiding first waveguide mode light and second waveguide mode light having a polarization direction perpendicular to that of the first waveguide mode light and amplifying the first waveguide mode light and the second waveguide mode light, the active layer having quantum wells such that projected quantization axes obtained by projecting quantization axes of the quantum wells thereof on a plane perpendicular to a light waveguide direction are inclined at 45.degree. with respect to vibration directions of electric field vectors of the first waveguide mode light and the second waveguide mode light; and an electrode for supplying a current to the active layer.

Abstract: In an optical communication system, a transmitted signal is modulated with a subcarrier signal having a frequency higher than the frequency of said transmitted signal on the transmission side, the modulated signal light emitted to a transmission channel. On the reception side, the received signal is filtered and decoded by means of a band-pass filter having a center frequency approximately equal to the frequency of the subcarrier signal of the received signal. The above arrangement makes it possible to achieve an arrangement free from the influence of deterioration in the degree of modulation due to spontaneous emission generated from an optical amplifier disposed midway along the transmission channel. The optical amplifier may be an optical differential gain amplifier which has the differential-gain optical input/output characteristics of outputting spontaneous emission of low intensity according to a digital signal value "0" and output light of high intensity according to a digital signal value "1".