Abstract: A grating type optical component is provided, in which a plurality of light beams having wavelengths different from one another can be reflected, the, loss is small, and the cost is low. The grating type optical component is composed of plural kinds of gratings (6a to 6d) that reflect different wavelengths of light and are formed at once in an optical fiber (2) and arranged serially in its longitudinal direction, so that there are no fusion splicing portions between the gratings. The plural kinds of serially-connected gratings (6a to 6d) are together housed in a temperature compensating package (3N) for compensating the temperature dependency of the gratings (6a to 6d). In forming the gratings (6a to 6d), prepare a phase mask (8N) in which a plurality of grating forming patterns (1a to 1d) different from one another are formed and arranged transversely. The phase mask (8N) covers the optical fiber (2) such that the grating forming patterns (1a to 1d) face the optical fiber (2).

Abstract: A grating type optical component is provided, in which a plurality of light beams having wavelengths different from one another can be reflected, the loss is small, and the cost is low. The grating type optical component is composed of plural kinds of gratings (6a to 6d) that reflect different wavelengths of light and are formed at once in an optical fiber (2) and arranged serially in its longitudinal direction, so that there are no fusion splicing portions between the gratings. The plural kinds of serially-connected gratings (6a to 6d) are together housed in a temperature compensating package (3N) for compensating the temperature dependency of the gratings (6a to 6d). In forming the gratings (6a to 6d), prepare a phase mask (8N) in which a plurality of grating forming patterns (1a to 1d) different from one another are formed and arranged transversely. The phase mask (8N) covers the optical fiber (2) such that the grating forming patterns (1a to 1d) face the optical fiber (2).

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 semiconductor laser module comprising a lens system having first and second lenses for coupling a beam emitted from a semiconductor laser with a core expanded fiber having a single-mode fiber end whose core diameter is expanded. The core expanded fiber is set so as to have a core expansion coefficient of 1.3 or more and an absolute value of change rate of mode field diameter smaller than 6.0.times.10.sup.-4 .mu.m.sup.-1.

Abstract: A laser diode array device (1, 11) according to a first aspect of the invention comprises a plurality of laser diode elements, some of which are formed as monitor laser diode elements for controlling the optical output of the remaining laser diode elements so that the device can operate at a power consumption rate by far lower than that of a conventional laser diode array device where the component laser diode elements needs to be individually controlled, while it can be assembled to an enhanced density. A laser diode array device (21) according to a second aspect of the invention comprises laser diode elements for signal transmission and monitor laser diode elements realized in the form of resonant cavities having a same length and sharing a common reflecting surface of a high-reflection film disposed at an end thereof so that the laser diode elements for signal transmission and the monitor laser diode elements show substantially identical light emitting characteristics.

Abstract: There is disclosed a coated optical fiber having a buffer layer around the outer periphery of an optical fiber. A curable resin reinforced coated layer made of reinforced fiber materials is disposed around the outer periphery of the buffer layer and a heatcurable resin is impregnated to the materials and cured. A curable resin layer having no fiber material is interposed between the buffer layer and the reinforced coated layer. The reinforced layer includes therein a multiplicity of elongated fiber materials.

Abstract: A method of exfoliating the coating of a coated optical fiber is described. A crack in the coating layer of the optical fiber is produced by bending means, cleaving the coating into a plurality of cleaved strip pieces while longitudinally enlarging the crack, and then cutting the strip pieces with an advantageous exfoliating tool. The exfoliating tool thus used is constructed to conveniently cleave the coating layer of the optical fiber and to cut the cleaved strip pieces. It does not damage the optical fiber upon exfoliating of the coating layer from the coated optical fiber, and can efficiently exfoliate the coating of the optical fiber.