Abstract: The power semiconductor module includes a base plate, a semiconductor chip mounted on a first main surface of the base plate, and a heat sink connected to a second main surface of the base plate, wherein: a chamfered part is provided at an end portion of at least one side of the second main surface; and, when the cross section of the base plate is viewed in a state in which the base plate is fixed to the heat sink, the slope of the second main surface of the base plate is discontinuous at the boundary between the chamfered part and an area of the second main surface other than the chambered part, and the angle between the bottom surface of the chamfered part of the base plate and the surface on the side of the heat sink where the base plate is fixed is 5° to 30°.

Abstract: A laser processing apparatus 1 includes a processing light source 3 emitting processing light; an observation light emitting unit 4 emitting observation light; optical fibers 19 conducting light having a plurality of wavelengths generated at an electronic component 2; a detecting unit 5 detecting the light conducted by the optical fibers 19; and a control unit 31 controlling a light emitting state of the processing light emitting unit 3. The optical fibers 19 are categorized into four groups, and disposed so as to surround an optical fiber 18 conducting the processing light. The optical fibers 19 categorized into the four groups are capable of conducting the observation light to the electronic component 2 every group.

Abstract: A metal heating apparatus according to an embodiment of the present invention comprises a light output portion for outputting light having a center wavelength in a wavelength range of 200 nm to 600 nm.

Abstract: A laser processing apparatus 1 includes a processing light source 3 emitting processing light; an observation light emitting unit 4 emitting observation light; optical fibers 19 conducting light having a plurality of wavelengths generated at an electronic component 2; a detecting unit 5 detecting the light conducted by the optical fibers 19; and a control unit 31 controlling a light emitting state of the processing light emitting unit 3. The optical fibers 19 are categorized into four groups, and disposed so as to surround an optical fiber 18 conducting the processing light. The optical fibers 19 categorized into the four groups are capable of conducting the observation light to the electronic component 2 every group.

Abstract: A fiber bundle is provided which has various advantages: limitation in terms of heat-resistant temperature is less; its manufacturing is easy and low-cost; and it will not degrade the optical fiber properties. The fiber bundle 10, which transmits through element fibers 11 light incident from light sources and emits the light from the respective output surface 11A altogether, has a structure in which at least one end parts of the element fibers 11 are collectively inserted into a metal sleeve 12 and the one end parts are solidified to be united with the sleeve 12, and in which a metal 13, that is a filler, is filled among the element fibers 11, in the sleeve 12, over a region of a given length L in the longitudinal direction of the sleeve 12 from the emitting-end face 12A of the sleeve 12.

Abstract: Provided is a semiconductor laser device having an economical structure in which the replacement of a semiconductor laser module is easy and in which the occurrence of dew condensation can be prevented while the increase in the lifetime as well as the stabilization and high output of laser output can be accomplished. The semiconductor laser device comprises semiconductor laser modules; a container main body which accommodates the semiconductor laser modules and which has an opening for taking out a semiconductor laser module outside; a lid provided at the opening in an openable and closable manner; and a means for cooling the semiconductor laser modules.

Abstract: A metal heating apparatus according to an embodiment of the present invention comprises a light output portion for outputting light having a center wavelength in a wavelength range of 200 nm to 600 nm.

Abstract: This invention relates to an optical transmission monitoring apparatus or the like which has a simple structure for identifying causes of variations in the power of WDM signals. The optical transmission monitoring apparatus includes a monitoring section for setting first and second wavelength bands in a monitor wavelength band, comparing variations in the optical powers of a plurality of types of light containing different light signals which are detected from the respective wavelength bands, and identifying causes of the variations in optical power in the optical transmission path.

Abstract: In an optical amplifier for wavelength-multiplexing transmission of this invention, signals of a plurality of wavelengths in a 1.55-&mgr;m wavelength band, which is input to an input terminal, sequentially passes through an optical isolator and optical coupler, and is input to an amplification optical fiber to be amplified. The signals amplified by and output from the amplification optical fiber sequentially passes through an optical isolator, optical coupler, optical isolator, and optical coupler, and is input to a further amplification optical fiber to be amplified. The signals amplified by and output from the further amplification optical fiber sequentially passes through an optical coupler, optical isolator, and optical coupler and is output from an output terminal. Each of an input-side optical amplifier and output-side optical amplifier performs constant output control.

Abstract: The present invention is to provide a multi-channel variable optical attenuator with a small size and a simple control circuitry, which requires a short time for adjusting the attenuation level of signal lights. The optical attenuator comprises an optical attenuating portion 10, a control circuitry 20 and a master control circuitry 21. The optical attenuating portion includes a plurality of optical waveguides 121-12N and a plurality of attenuation adjusting portions 131-13N, both of which is formed in a substrate 11. A signal light of a specific wavelength &lgr;i, which is derived from the wavelength multiplexed light, transmits in a respective waveguide 12i and is attenuated by a specific amount at the attenuation adjusting portion 13i. The control circuitry 20outputs a plurality of control signals 141-14N to attenuation adjusting portions 131-13N so that the attenuation in each optical waveguides 121-12N is varied by the specific amount to the master control 22 sent from the master control circuitry 21.

Abstract: This method comprises the steps of: introducing light signals having different wavelengths into an optical amplifier, wherein the optical amplifier has a plurality of fibers with rare earth element doped therein and P is selectively doped in said fibers; and introducing excitation light into the fibers, the excitation light being able to excite the rare earth element. At least one of the fibers has Al therein and the relationship between the Al and P concentration satisfies following expression: C(P)/C(Al)>2, where, C(P) is P concentration in the fiber, and C(Al) is Al concentration in the fiber.

Abstract: An optical fiber amplifier comprises a composite optical fiber for receiving signal light and excitation light, amplifying the signal light and emitting the amplified signal light, comprising at least two kinds of optical fibers serially coupled each having a glass composition selected from at least two kinds of rare-earth-doped glass compositions, and excitation means for generating excitation light and supplying it to the composite optical fiber. Then, an optical fiber amplifier which reduces the wavelength dependency of gain in various wavelength ranges in wavelength division multiplexing transmission or in optical analog transmission, and which maintains an energy efficiency for amplification, an optical fiber amplifier which makes a wavelength at a gain peak to a predetermined one in accordance with intensities of various input lights, and an optical amplifier repeater comprising this optical fiber amplifier are provided.

Abstract: An optical amplifier for amplifying light having first and second signals includes an optical circulator for outputting light input from a first port through a second port, and outputting light input from the second port through a third port. A first amplifier for amplifying light passing therethrough is connected to the second port. A second amplifier for amplifying light passing therethrough is connected to the first amplifier. A first reflector for reflecting the first light signal, and transmitting the second light signal is arranged between the first and second amplifiers and a second reflector for reflecting the second light signal is arranged such that the second amplifier is located between the first and second reflectors. A separate branch may be connected to compensate for time difference experienced by the first and second signals when traveling through the first and second amplifiers.

Abstract: An optical fiber amplifier comprises a composite optical fiber for receiving signal light and excitation light, amplifying the signal light and emitting the amplified signal light, comprising at least two kinds of optical fibers serially coupled each having a glass composition selected from at least two kinds of rare-earth-doped glass compositions, and excitation means for generating excitation light and supplying it to the composite optical fiber. Then, an optical fiber amplifier which reduces the wavelength dependency of gain in various wavelength ranges in wavelength division multiplexing transmission or in optical analog transmission, and which maintains an energy efficiency for amplification, an optical fiber amplifier which makes a wavelength at a gain peak to a predetermined one in accordance with intensities of various input lights, and an optical amplifier repeater comprising this optical fiber amplifier are provided.

Abstract: An object of this invention is to provide a mode field diameter conversion optical fiber which can be processed in a short period of time to have a reduced mode field diameter at a desired portion thereof. The optical fiber according to this invention comprises a core of silica glass having a residual tensile stress, and a cladding surrounding the core and having a lower refractive index than that of the core. The desired portion is heated to relax the residual tensile stress in the core, whereby the optical fiber has a reduced mode field diameter at the desired portion.

Abstract: There is disclosed an optical waveguide comprising a core portion made of a light propagating material and a cladding portion, a first dopant and a second dopant being induced into said core portion, the first dopant having a function of increasing a refractive index of the light propagating material and having a first thermal diffusion coefficient to said light propagating material, the second dopant having a function of decreasing the refractive index of said light propagating material and having a second thermal diffusion coefficient to the light propagating material larger than the first thermal diffusion coefficient under a predetermined temperature.

Abstract: An optical functioning glass for enabling optical amplification at 1.3-.mu.m wavelength band or increasing efficiency of the amplification is disclosed. The optical functioning glass contains Nd.sup.3+ as an active material and uranium, both of which are doped in a multi-component function glass serving as a host glass. Since uranium is doped in the optical functioning glass, light emission of Nd.sup.3+ in the 1.06-.mu.m wavelength band can be absorbed by uranium. A decrease in efficiency of induced emission in a 1.3-.mu.m wavelength band can be prevented, and an optical functioning glass suitable for optical amplification in the 1.3-.mu.m wavelength band can be obtained. When a fiber is formed using the optical functioning glass as a core, a low-threshold, high-gain fiber amplifier, fiber laser, and the like can be obtained.

Abstract: An optically active device comprising an optical fiber, a light source and a coupler is disclosed. The optical fiber has a core made of a silicate glass containing Rb and/or Cs oxide. The core is doped with Nd.sup.3+ as an active ion and transmits light at 1.3 .mu.m band. The light source generates excitation light at 0.8 .mu.m. The coupler directs the excitation light from the light source into the core of the optical fiber. A signal light or a spontaneous light at 1.3 .mu.m band which is transmitted in the core stimulates Nd.sup.3+ to emit light at 1.3 .mu.m band. As a result an optical function such as optical amplification can be effected at 1.3 .mu.m band.

Abstract: The present invention relates to an optical functioning glass containing Nd.sup.+3 as an active ion which amplifies an input light, and at least one other optical active ion different from Nd.sup.+3 which absorbs light at and near 1 .mu.m. The present invention also relates to an optical functioning glass containing Nd.sup.+3 as an active ion which amplifies the input light, and at least one other optical active ion different from Nd.sup.+3 functioning as a promoter. An efficiency of the stimulated emission of Nd.sup.3+ caused by signal light propagated through the optical functioning glass is enhanced and a gain of the light amplification at 1.3 .mu.m is increased.

Abstract: An optical functioning glass for enabling optical amplification at 1.3-.mu.m wavelength band or increasing efficiency of the amplification is disclosed. The optical functioning glass contains Nd.sup.3+ as an active material and uranium, both of which are doped in a multi-component function glass serving as a host glass. Since uranium is doped in the optical functioning glass, light emission of Nd.sup.3+ in the 1.06-.mu.m wavelength band can be absorbed by uranium. A decrease in efficiency of induced emission in a 1.3-.mu.m wavelength band can be prevented, and an optical functioning glass suitable for optical amplification in the 1.3-.mu.m wavelength band can be obtained. When a fiber is formed using the optical functioning glass as a core, a low-threshold, high-gain fiber amplifier, fiber laser, and the like can be obtained.