Abstract: An optical module, which is arranged in an optical transmission path, includes an optical amplifying unit configured with a semiconductor, wherein the optical amplifying unit amplifies light input from the optical transmission path, and an optical element configured with a semiconductor, wherein the optical element propagates the light amplified by the optical amplifying unit to the optical transmission path.

Abstract: An optical transmitter has a case. The case houses a laser beam generator, a lens, a cooler, and a high heat conductivity member. The lens concentrates the laser beam generated by the laser beam generator and leads the laser beam to an optical fiber. The high heat conductivity member is arranged between the laser beam generator and the lens and the cooler. The laser beam generator has higher heat conductivity than that of the case. The laser beam generator conveys the heat generated in the laser beam generator to the cooler.

Abstract: A directional coupler type optical modulator with traveling-wave electrodes includes a first directional coupler region, a waveguide wave coupling region, a second directional coupler region, and a set of noncrossing traveling-wave electrodes disposed along the outside of the waveguides. The electrodes of each directional coupler are connected to the traveling-wave electrodes via air-bridges. The waveguide structures are of the P-I-N type having a common N-type conducting layer which provides delta-beta operation of the directional coupler, and both cross and bar states are controlled by a single input signal.

Abstract: An optical transmitter has a case. The case houses a laser beam generator, a lens, a cooler, and a high heat conductivity member. The lens concentrates the laser beam generated by the laser beam generator and leads the laser beam to an optical fiber. The high heat conductivity member is arranged between the laser beam generator and the lens and the cooler. The laser beam generator has higher heat conductivity than that of the case. The laser beam generator conveys the heat generated in the laser beam generator to the cooler.

Abstract: An optical module, which is arranged in an optical transmission path, includes an optical amplifying unit configured with a semiconductor, wherein the optical amplifying unit amplifies light input from the optical transmission path, and an optical element configured with a semiconductor, wherein the optical element propagates the light amplified by the optical amplifying unit to the optical transmission path.

Abstract: A directional coupler type optical modulator with traveling-wave electrodes includes a first directional coupler region, a waveguide wave coupling region, a second directional coupler region, and a set of noncrossing traveling-wave electrodes disposed along the outside of the waveguides. The electrodes of each directional coupler are connected to the traveling-wave electrodes via air-bridges. The waveguide structures are of the P-I-N type having a common N-type conducting layer which provides delta-beta operation of the directional coupler, and both cross and bar states are controlled by a single input signal.