Abstract: Provided is a spectrometer capable of separating a particular wavelength component from light including a plurality of wavelength components by means of a small, simple configuration. The spectrometer comprises a filter part configured to transmit a specific wavelength component of light incident onto an incident surface. An illuminating means is configured to cause the light to be incident at respectively different incident angles onto a plurality of incident positions at different positions in the longer direction of the incident surface.

Abstract: Methods of optimizing optical alignment in an optical package are provided. In one embodiment, the optical package includes a laser diode, a wavelength conversion device, coupling optics positioned along an optical path extending from the laser diode to the wavelength conversion device, and one or more adaptive actuators. The method involves adjusting the optical alignment of the wavelength conversion device in a non-adaptive degree of freedom by referring to a thermally-dependent output intensity profile of the laser diode and a thermally-dependent coupling efficiency profile of the optical package.

Abstract: A diffractive optical element has a diffraction grating which multiplexes light beams of different wavelengths, and the diffraction grating has a binary structure in which the diffraction surface top part and the diffraction surface bottom part repeat a concave and convex shape through a rising surface part along an optical axis direction P. The diffraction surface top part and the diffraction surface bottom part are inclined to the rising surface part. By this diffractive optical element, the diffraction angle of the light beam is maintained, and the diffraction efficiency of the light beam can be improved. By using this diffractive optical element in an optical communication module, while the separation angle of the light beam of the different wavelength is maintained, the signal receiving performance is increased.

Abstract: A second harmonic generation device includes: a case having an opening; a light source apparatus fixed to the case; a sleeve storing in its center hole a nonlinear optical crystal chip in which an optical waveguide propagating light irradiated from the light source apparatus and converting the light into a second harmonic wave light is formed, and having an outer shape which is fitted to play in the opening; and a coupling optical system which is disposed in the case and couples light irradiated from the light source apparatus with the optical waveguide, wherein the sleeve is inserted into the opening and fixed with respect to the case.

Abstract: Methods of optimizing optical alignment in an optical package are provided. In one embodiment, the optical package includes a laser diode, a wavelength conversion device, coupling optics positioned along an optical path extending from the laser diode to the wavelength conversion device, and one or more adaptive actuators. The method involves adjusting the optical alignment of the wavelength conversion device in a non-adaptive degree of freedom by referring to a thermally-dependent output intensity profile of the laser diode and a thermally-dependent coupling efficiency profile of the optical package.

Abstract: The present invention is provided to obtain an inexpensive bidirectional optical module wherein a diffraction efficiency can be maximized at different diffraction order for light beam with different wavelength, and light usage efficiency is enhanced. The bidirectional optical module includes a light-emitting element for transmitting an optical signal toward an end of an optical fiber; a light-receiving element for receiving an optical signal from the end of the optical fiber; and a grating in which stair shapes are repeated with a predefined pitch. In the bidirectional optical module, a phase function is defined as phase-difference contour lines which is formed by making two light fluxes from predetermined positions interfere with each other on a surface arranged at a position of the grating. A planar pitch of the grating is formed such that values of the phase function form phase contour lines each representing an integer multiple of 360 degrees.

Abstract: An inexpensive optical bi-directional module by which diffraction efficiency of light beams having different wavelengths can be maximized at different diffraction orders, respectively, and light utilization efficiency is enhanced. The optical bi-directional module comprises a light emitting element for transmitting an optical signal toward the end of an optical fiber, a light receiving element for receiving an optical signal from the end of the optical fiber, and a grating having stepwise profiles repeated at a desired pitch. Assuming the position of the grating is on the DOE plane and the light emitting elements are located, respectively, at the end of the optical fiber and the position of the light receiving element, planar pitch of the grating is set such that a phase function being given as an equiphase-difference line on the DOE plane by causing interference of two light beams of the assumed light emitting elements has a phase function value representing an equiphase curve of integral multiples of 360°.

Abstract: A diffractive optical element has a diffraction grating which multiplexes light beams of different wavelengths, and the diffraction grating has a binary structure in which the diffraction surface top part and the diffraction surface bottom part repeat a concave and convex shape through a rising surface part along an optical axis direction P. The diffraction surface top part and the diffraction surface bottom part are inclined to the rising surface part. By this diffractive optical element, the diffraction angle of the light beam is maintained, and the diffraction efficiency of the light beam can be improved. By using this diffractive optical element in an optical communication module, while the separation angle of the light beam of the different wavelength is maintained, the signal receiving performance is increased.

Abstract: An echelon type diffraction structure 5a is formed on the flat optical surface of a lens 5, thereby ensuring easy designing and easy production of a diffraction structure as a microstructure. Further, the light of wavelength ?1 is applied to the diffraction structure 5a in a tilted position with respect to the optical axis of the lens 5 so that the first order diffracted light produced by the diffraction structure 5a travels along or parallel to the optical axis of the lens 5, with the result that improved light transmittance can be maintained. Further, a lens 7b is arranged between a light emitting device 7a and lens 5. Thus, the flat optical surface of the lens 5 is arranged on the side of the end face 1a of an optical fiber 1, thereby reducing the deterioration in aberration more effectively.

Abstract: A diffractive optical element 1 has a diffraction grating which multiplexes the light beam of the different wavelength, and the diffraction grating is structured by a binary structure in which the diffraction surface top part 2 and the diffraction surface bottom part 4 repeat the concave and convex shape through a rising surface 3 part along the optical axis direction P, and the diffraction surface top part and the diffraction surface bottom part are inclined to the rising surface part. By this diffractive optical element 1, the diffraction angle of the light beam is maintained, and the diffraction efficiency of the light beam can be improved. Then, by using this diffractive optical element 1, the optical communication module in which, while the separation angle of the light beam of the different wavelength is maintained, the signal receiving performance is increased, can be provided.

Abstract: An optical bidirectional module 10 having therein light emitting element 11 which transmits optical signal to the end facet of the optical fiber, light receiving element 12 which receives optical signal from the end facet of the optical fiber and stair-shaped multi-level grating 15, wherein the stair-shaped multi-level grating separates the first light path between the end facet of optical fiber and the light emitting element and the second light path between the end facet of optical fiber and the light receiving element by a different wavelength of each optical signal, when the module mixes and separates optical signal with different wavelengths traveling in opposite directions related to the end facet of the optical fiber 1, used for bidirectional optical fiber communication by means of a wavelength multiplex system.

Abstract: An echelon type diffraction structure 5a is formed on the flat optical surface of a lens 5, thereby ensuring easy designing and easy production of a diffraction structure as a microstructure. Further, the light of wavelength ?1 is applied to the diffraction structure 5a in a tilted position with respect to the optical axis of the lens 5 so that the first order diffracted light produced by the diffraction structure 5a travels along or parallel to the optical axis of the lens 5, with the result that improved light transmittance can be maintained. Further, a lens 7b is arranged between a light emitting device 7a and lens 5. Thus, the flat optical surface of the lens 5 is arranged on the side of the end face 1a of an optical fiber 1, thereby reducing the deterioration in aberration more effectively.

Abstract: An optical multiplex communication system includes a multiplexer and a demultiplexer. In the multiplexer, one of two modulated optical pulse train signals is attenuated by an optical attenuator so that amplitudes of the two signals differ from each other. Then, the two signals are time-division multiplexed to produce a multiplexed optical pulse train signal. In the demultiplexer, a VD detector indirectly derives the amplitude of the extracted optical pulse train signal and outputs it to a comparator. A VR detector derives the mean amplitude of the multiplexed optical pulse train signal and outputs it to the comparator. Based on the inputted amplitudes, the comparator identifies the extracted optical pulse train signal. A controller and a mixer control the signal extraction timing such that the extracted optical pulse train signal as identified by the comparator agrees with selection designated by an externally inputted select signal.

Abstract: An optical bidirectional module 10 having therein light emitting element 11 which transmits optical signal to the end facet of the optical fiber, light receiving element 12 which receives optical signal from the end facet of the optical fiber and stair-shaped multi-level grating 15, wherein the stair-shaped multi-level grating separates the first light path between the end facet of optical fiber and the light emitting element and the second light path between the end facet of optical fiber and the light receiving element by a different wavelength of each optical signal, when the module mixes and separates optical signal with different wavelengths traveling in opposite directions related to the end facet of the optical fiber 1, used for bidirectional optical fiber communication by means of a wavelength multiplex system.

Abstract: A semiconductor optical modulator having an electroabsorptive layer and a pair of modulating voltage electrodes also has a direct-current voltage electrode, from which an unmodulated electric field can be applied to the electroabsorptive layer to adjust the output optical power level. The output optical power level can thus be adjusted without the need for an external attenuator, and without shifting the modulating voltage away from the part of the extinction ratio characteristic having the best linearity. An optical multiplexing module using semiconductor optical modulators of this type can generate a multiplexed output signal with a uniform optical power level simply by controlling the direct-current voltages applied to the semiconductor optical modulators.

Abstract: A developing roller for electrophotography is disclosed which is composed of a conductive mandrel, a charge-providing layer having a charge-providing performance to a non-magnetic one-component toner, formed at the surface of the roller, a base layer having an elasticity, formed at a position nearer to the mandrel of the roller than the charge-providing layer and an elastic intermediate layer formed at a position between the base layer and the charge-providing layer. The elastic intermediate layer is formed of a composition having a contact angle to water which is smaller than that of a composition for forming the base layer. Also, disclosed are a developing apparatus, an apparatus unit and an image forming apparatus using the developing roller.

Abstract: A semiconductor optical modulator having an electroabsorptive layer and a pair of modulating voltage electrodes also has a direct-current voltage electrode, from which an unmodulated electric field can be applied to the electroabsorptive layer to adjust the output optical power level. The output optical power level can thus be adjusted without the need for an external attenuator, and without shifting the modulating voltage away from the part of the extinction ratio characteristic having the best linearity. An optical multiplexing module using semiconductor optical modulators of this type can generate a multiplexed output signal with a uniform optical power level simply by controlling the direct-current voltages applied to the semiconductor optical modulators.

Abstract: A developing roller for electrophotography is disclosed which is composed of a conductive mandrel, a charge-providing layer having a charge-providing performance to a non-magnetic one-component toner, formed at the surface of the roller, a base layer having an elasticity, formed at a position nearer to the mandrel of the roller than the charge-providing layer and an elastic intermediate layer formed at a position between the base layer and the charge-providing layer. The elastic intermediate layer is formed of a composition having a contact angle to water which is smaller than that of a composition for forming the base layer. Also, disclosed are a developing apparatus, an apparatus unit and an image forming apparatus using the developing roller.

Abstract: The WDM light source comprises a light source which generates an optical signal for an optical channel. The optical signal is intensity modulated with modulating signals. The modulated optical signal is applied to a dispersion generating circuit, at which dispersion occurs on the optical signal, according to the wavelength of the signal. A phase difference detector detects phase difference between the optical signal input to the dispersion generating circuit and the optical signal output from the dispersion generating circuit. According to the detected phase difference, the control signal which corresponds to delay time is generated. The control signal is fed back to the light source thus the wavelength of the light source is controlled.

Abstract: A developing roller for electrophotography is disclosed which is composed of a conductive mandrel, a charge-providing layer having a charge-providing performance to a non-magnetic one-component toner, formed at the surface of the roller, a base layer having an elasticity, formed at a position nearer to the mandrel of the roller than the charge-providing layer and an elastic intermediate layer formed at a position between the base layer and the charge-providing layer. The elastic intermediate layer is formed of a composition having a contact angle to water which is smaller than that of a composition for forming the base layer. Also, disclosed are a developing apparatus, an apparatus unit and an image forming apparatus using the developing roller.