Abstract: A semiconductor optical modulator includes optical input and output portions; a plurality of Mach-Zehnder modulators, each including first and second waveguide arms having first and second modulation electrodes, respectively; an optical demultiplexer coupled between the optical input portion and the Mach-Zehnder modulators through an optical waveguide; an optical multiplexer coupled between the optical output portion and the Mach-Zehnder modulators; a plurality of electrical inputs; and a plurality of differential transmission lines electrically connecting the electrical inputs to the Mach-Zehnder modulators. The first modulation electrode and the second modulation electrode of at least one of the Mach-Zehnder modulators, one of the electrical inputs, and one of the differential transmission lines that connects such one electrical input to such one Mach-Zehnder modulator form an electrical circuit having a differential impedance in a range of 80? to 95?.

Abstract: A transmitter optical module for emitting a polarization combined beam is disclosed. The transmitter optical module includes optical sources each emitting optical beams with polarizations substantially same with others, an optical isolator, and a polarization beam combiner (PBC). The optical isolator, by receiving the optical beams, outputs the optical beams with polarizations perpendicular to the other to the PBC.

Abstract: An optical module that processes an input optical signal and outputs a processed optical signal is disclosed. The optical module provides a housing and an optical processing device in the housing. The housing provides an optical input port and an optical output port in a first wall thereof in side-by-side arrangement. A third wall of the housing only provides RF terminals. Second and fourth walls of the housing provide DC terminals. Electrical connection between the DC terminals with DC pads on the device is realized through a wiring substrate whose top avoids an optical path from the optical input port to the input port of the device.

Abstract: A semiconductor optical modulator includes optical input and output portions; a plurality of Mach-Zehnder modulators including first and second waveguide arms having first and second modulation electrodes, respectively; an optical demultiplexer coupled between the optical input portion and the Mach-Zehnder modulator through an optical waveguide; an optical multiplexer coupled between the optical output portion and the Mach-Zehnder modulator; a plurality of electrical inputs including first, second, and common electrodes disposed between the first and second electrodes; and a plurality of differential transmission lines electrically connecting the electrical inputs to the Mach-Zehnder modulators. The Mach-Zehnder modulators, the optical demultiplexer, the optical multiplexer, the electrical inputs, and the differential transmission lines are disposed on a single substrate.

Abstract: An optical assembly (OSA) that installs a semiconductor optical device mounted on a thermo-electric controller (TEC) is disclosed. The TEC in the upper plate thereof is mechanically connected to the housing, or to the block stiffly fixed to the housing by a bridge made of stiff material. The bridge preferably extends along the optical axis to show enhanced durability against the impact caused by an external ferrule abutting against the receptacle of the OSA.

Abstract: An optical assembly (OSA) that installs a semiconductor optical device mounted on a thermo-electric controller (TEC) is disclosed. The TEC in the upper plate thereof is mechanically connected to the housing, or to the block stiffly fixed to the housing by a bridge made of stiff material. The bridge preferably extends along the optical axis to show enhanced durability against the impact caused by an external ferrule abutting against the receptacle of the OSA.

Abstract: An optical semiconductor device includes: a beam splitter that splits an input optical axis into a first split axis having a first split angle and a second split axis having a second split angle larger than the first split angle; a first unit that is located on the first split axis of the beam splitter and has one or more optical components, an interval between a more distant end of the first unit and the beam splitter having a first length; a second unit that is located on the second split axis of the beam splitter and has one or more optical components, an interval between a more distant end of the second unit and the beam splitter having a second length larger than the first length; and an optical semiconductor element that has a first outputting end having a first output axis coupled optically to the input optical axis of the beam splitter, a second outputting end having a second output axis, and optical gain, the optical semiconductor element being inclined so that the second output axis is arranged away

Abstract: A flexible printed circuit board includes: a substrate having a first edge and a second edge; a first wiring pattern disposed on the substrate and having a lead connection portion at a side of the first edge of the substrate; a second wiring pattern disposed on the substrate and having a lead connection portion at a side of the first edge of the substrate; a first solder pattern disposed on the lead connection portion of the first wiring pattern; and a second solder pattern disposed on the lead connection portion of the second wiring pattern and having a length longer than the first solder pattern.

Abstract: A laser device includes a cavity and a control portion. The cavity has an optical amplifier, a wavelength selectable portion having a changeable transmission wavelength range, and a mirror. The control portion controls the wavelength selectable portion so that the transmission wavelength range of the wavelength selectable portion is changed to a given range. The control portion controls the wavelength selectable portion so that the cavity outputs a desirable lasing wavelength light and optical intensity of the desirable lasing wavelength light is a given value, after controlling the wavelength selectable portion so that the cavity outputs the desirable lasing wavelength light.

Abstract: An optical assembly (OSA) that installs a semiconductor optical device mounted on a thermo-electric controller (TEC) is disclosed. The TEC in the upper plate thereof is mechanically connected to the housing, or to the block stiffly fixed to the housing by a bridge made of stiff material. The bridge preferably extends along the optical axis to show enhanced durability against the impact caused by an external ferrule abutting against the receptacle of the OSA.

Abstract: An optical semiconductor device includes: a beam splitter that splits an input optical axis into a first split axis having a first split angle and a second split axis having a second split angle larger than the first split angle; a first unit that is located on the first split axis of the beam splitter and has one or more optical components, an interval between a more distant end of the first unit and the beam splitter having a first length; a second unit that is located on the second split axis of the beam splitter and has one or more optical components, an interval between a more distant end of the second unit and the beam splitter having a second length larger than the first length; and an optical semiconductor element that has a first outputting end having a first output axis coupled optically to the input optical axis of the beam splitter, a second outputting end having a second output axis, and optical gain, the optical semiconductor element being inclined so that the second output axis is arranged away

Abstract: A laser module has an optical amplifier, a first etalon and a wavelength selectable mirror. The first etalon has wavelength peaks at a given wavelength interval in transmission characteristics and transmits a light from the optical amplifier. The wavelength peaks are tunable. The wavelength selectable mirror acts as an external mirror of an external cavity laser including the optical amplifier, and has a relatively high reflection intensity at a part of wavelength range in an effective gain range of the optical amplifier. The effective gain range of the optical amplifier includes more than one wavelength peak of the first etalon. A reflection bandwidth where the wavelength selectable mirror has a relatively high reflection intensity is less than twice of the wavelength interval of the wavelength peaks of the first etalon.

Abstract: A laser device includes a cavity and a control portion. The cavity has an optical amplifier, a wavelength selectable portion having a changeable transmission wavelength range, and a mirror. The control portion controls the wavelength selectable portion so that the transmission wavelength range of the wavelength selectable portion is changed to a given range. The control portion controls the wavelength selectable portion so that the cavity outputs a desirable lasing wavelength light and optical intensity of the desirable lasing wavelength light is a given value, after controlling the wavelength selectable portion so that the cavity outputs the desirable lasing wavelength light.

Abstract: A laser module has an optical amplifier, a first etalon and a wavelength selectable mirror. The first etalon has wavelength peaks at a given wavelength interval in transmission characteristics and transmits a light from the optical amplifier. The wavelength peaks are tunable. The wavelength selectable mirror acts as an external mirror of an external cavity laser including the optical amplifier, and has a relatively high reflection intensity at a part of wavelength range in an effective gain range of the optical amplifier. The effective gain range of the optical amplifier includes more than one wavelength peak of the first etalon. A reflection bandwidth where the wavelength selectable mirror has a relatively high reflection intensity is less than twice of the wavelength interval of the wavelength peaks of the first etalon.

Abstract: An optical semiconductor device includes a package body, a laser diode accommodated in the package body, a temperature regulation block connected thermally to the laser diode, an optical filter connected thermally to the temperature regulation block, a photodetector receiving the laser beam from the laser diode via the optical filter, a feeder feeding a driving power to the laser diode, and a thermal conducting body provided separately to the feeder, wherein the thermal conducting body transmits the temperature of the package body to the laser diode.

Abstract: Disclosed is a process for the preparation of maleic anhydride which comprises subjecting an aliphatic hydrocarbon having four or more carbon atoms to gas phase oxidation reaction in the presence of a catalyst, wherein supposing that the function of reaction product gas composition is FL and the function of temperature and pressure of reaction product gas is FR, the safety index F satisfies the following relationship (1): F=FL−FR>0  (1) According to the present invention, it is possible that the loss of unreacted hydrocarbon and maleic anhydride as reaction product due to non-catalytic oxidation reaction is prevented while effecting the reaction in a stable manner, whereby the yield of maleic anhydride can be kept maximum while assuring safety.

Abstract: An optical semiconductor device includes a package body, a laser diode accommodated in the package body, a temperature regulation block connected thermally to the laser diode, an optical filter connected thermally to the temperature regulation block, a photodetector receiving the laser beam from the laser diode via the optical filter, a feeder feeding a driving power to the laser diode, and a thermal conducting body provided separately to the feeder, wherein the thermal conducting body transmits the temperature of the package body to the laser diode.