Abstract: Wavelength multiplex transmission is realized in which the temperature dependency of an EDFA is compensated for in relation to the wavelengths which are used. A first and a second long-period grating which have different periods from each other are formed in an optical fiber, ensuring that the peak wavelength of a waveform representing an optical transmission loss characteristic of the first long-period grating side is located on the shorter wavelength side than a transmission band and a peak wavelength of a waveform representing an optical transmission loss characteristic of the second long-period grating side is located on the longer wavelength side within the transmission band.

Abstract: An optical amplifier of the present invention comprises a pumping light source configured to output a pumping light, an amplifier unit configured to receive the pumping light from said pumping light source and amplify an optical signal that passes therethrough, and an optical fiber disposed between said pumping light source and said amplifier unit, said optical fiber including an optical filter that is configured to attenuate the optical signal from said amplifier unit.

Abstract: In a discharge lamp device, the arc tube body is configured by welding and integrating shroud glass with an arc tube so as to enclose a discharging portion, and a rearward elongating portion of the arc tube that elongates in the rear of the shroud glass is inserted and held into an opening of an insulating plug which is made of synthetic resin. A UV blocking film is formed on the outer surface of the rearward elongating portion of the arc tube. UV components of leakage light from the rearward elongating portion are cut off, and the amount of ultraviolet rays to which the resin layer in the opening is exposed is reduced. The UV blocking film is in the opening, and hence cannot be seen through a front lens.

Abstract: In a discharge bulb having an arc tube formed with pinch seal portions on both ends of a sealed glass bulb that is a light-emitting discharge section, infrared transmitting films for blocking visible light and transmitting infrared light are applied to at least the pinch seal portions of the arc tube to prevent visible light from exiting the pinch seal portions and to suppress generation of glare. Infrared light from the pinch seal portions can pass through the infrared transmitting films, which prevents accumulation of heat in the arc tube (pinch seal portions and sealed glass bulb), thereby preventing the temperature of the arc tube from increasing excessively.

Abstract: An optical amplifier of the present invention comprises a pumping light source configured to output a pumping light, an amplifier unit configured to receive the pumping light from said pumping light source and amplify an optical signal that passes therethrough, and an optical fiber disposed between said pumping light source and said amplifier unit, said optical fiber including an optical filter that is configured to attenuate the optical signal from said amplifier unit.

Abstract: Wavelength multiplex transmission is realized in which the temperature dependency of an EDFA is compensated for in relation to the wavelengths which are used. A first and a second long-period grating which have different periods from each other are formed in an optical fiber, ensuring that the peak wavelength of a waveform representing an optical transmission loss characteristic of the first long-period grating side is located on the shorter wavelength side than a transmission band and a peak wavelength of a waveform representing an optical transmission loss characteristic of the second long-period grating side is located on the longer wavelength side within the transmission band.

Abstract: An insulating plug, for a discharge lamp device, including a plug body and a lamp-side connector. The plug body is made of a glass-fiber-reinforced plastic resin. The lamp-side connector is provided at a rear end portion of the plug body. A power-supplying connector can be attached to, and detached from, the lamp-side connector. The plug body has an arc tube fixedly held thereon, so as to form a discharge lamp device. Because the plug body is made of a glass-fiber-reinforced plastic resin, the durability, molding precision, and so on of the plug body and, hence, those of the discharge lamp device provided with this plug body, are enhanced.

Abstract: The temperature dependency of an EDFA is compensated in a wavelength of 1570 to 1600 nm to realize a wavelength division multiplexing transmission. First and second long period gratings different in grating period from each other are formed in an optical fiber. The peak wavelength of the waveform of the light transmission loss characteristic of the first long period grating is formed on the shorter wavelength side than a transmission band. The peak wavelength of the waveform of the light transmission loss characteristic of the second long period grating is formed on the longer wavelength side than a transmission band.

Abstract: A grating-type optical component having a high isolation ability at a light-blocking band and a small clad layer mode combination loss at a signal transmission band, and its manufacturing method are provided. A selected area on a core of an optical fiber is irradiated by ultraviolet beams emitted from an excimer laser source through a phase mask in order to produce high index of refraction areas and low index of refraction areas arranged alternately and periodically along the longitudinal axis of the optical fiber. This ultraviolet irradiation is terminated before the index of refraction, which is increasing due to the ultraviolet irradiation, reaches a target value. Then, the phase mask is removed, and the selected area of the core is again irradiated by ultraviolet beams, thereby completing the grating-type optical fiber.

Abstract: A projection-type headlamp for an automotive vehicle including a projection lens made of glass through which light rays emitted from a discharge lamp bulb are radiated to an outer lens made of a synthetic resin. An ultraviolet absorbing film made solely of zinc oxide is formed on the inner surface of the projection lens, which film prevents discoloration (yellowing) and deterioration (cracking) of the outer lens due to ultraviolet irradiation from the discharge bulb. A protective film is provided over the ultraviolet absorbing film so as to retain the ultraviolet absorbing function of the latter for an extended service period.

Abstract: The invention relates to a dispersion slope compensating optical fiber which compensates the chromatic dispersion and dispersion slope of a positive dispersion slope optical fiber such as TRUE WAVE and increases reliability of wavelength division multiplex transmission in a wavelength from 1530 nm to 1610 nm. The center core (3) is covered by a side core layer (4), and the outside thereof is covered by a cladding layer (5), wherein the relationship between the relative refractive index differences .DELTA.1, .DELTA.2, .DELTA.3 of the center core (3), side core layer (4) and cladding layer (5) and pure SiO.sub.2 glass is established to be .DELTA.1) .DELTA.3) .DELTA.2, .DELTA.2/.DELTA.1=Rd.ltoreq.-0.45, and .DELTA.1.gtoreq.1.2%. The average dispersion slope in a wavelength from 1530 nm to 1610 nm is established to be -0.6 ps/nm.sup.