Abstract: An athermal arrayed-waveguide grating is disclosed and includes an input waveguide for inputting two or more optical signals from one exterior side, a grating array for separating the optical signals into different wavelengths of light, a first slab, formed with two layers and having different refractive indices from each other, for connecting the input waveguide with the grating array, a second slab for causing the different light wavelengths separated at the grating array to be imaged on an egress surface thereof, and an output waveguide array for outputting each light wavelength imaged on the egress surface of the second slab to the other exterior side in the form of a separated channel.

Abstract: Disclosed is a wavelength-division multiplexer for providing a plurality of optical-signal-transmitting channels by dividing an input-optical-signal band. The wavelength-division multiplexer includes an optical block for dividing the input-optical-signal band into a plurality of bragg wavelengths including side lobes and for accommodating a plurality of bragg-fiber gratings connected to each other in series, such that a peak of a side lobe is matched with the optical-signal-transmitting channel. An isolator is provided to shut off a part of the wavelengths of the input-optical-signal band, which is reflected from the bragg-fiber gratings. A planar waveguide-array-grating chip divides the input-optical-signal band, which is inputted from the optical-fiber block, into a plurality of channels. An output-terminal optical-fiber block is connected to an output terminal of the planar waveguide-array-grating chip.

Abstract: Disclosed is a variable alignment-type optical fiber block in which alignment of waveguides can be changed according to temperature. The optical fiber block includes: a substrate having a receiving section formed at one end of the substrate, the receiving section having a predetermined volume; a ferrule seated in the receiving section, the ferrule having a hole in which an optical fiber is inserted; a first expandable block disposed between one side surface of the ferrule and an inner wall surface of the receiving section, which are opposed to each other, the first expandable block having a first thermal expansive coefficient; and, a second expandable block disposed between the other side surface of the ferrule and another inner wall surface of the receiving section, which are opposed to each other, the second expandable block having a second thermal expansive coefficient.

Abstract: A gain flattening device for an optical fiber amplifier. In the gain flattening device, a first end portion, having first and second ends, receives an amplified optical signal from a first amplification fiber via the first end. A second end portion, having third and fourth ends, outputs the amplified optical signal to a second amplification fiber via the fourth end. A first connector is included for connecting the first end to the third end. A second connector is included for connecting the second end to the fourth end. At least one reflective grating is further included with a predetermined gain curve at a predetermined wavelength band. An optical coupling portion couples the amplified optical signal from the first connector to the second connector in at least one coupling region where the first and second connectors are closer to each other than in any other area, and outputs part of the amplified optical signal reflected from the reflective grating via the second end.

Abstract: A packaging device for alignment between a planar lightguide circuit and an optical-fiber block is disclosed. The device includes a planar lightguide circuit and a single optical-fiber block. The planar lightguide circuit includes an input port of an input waveguide, a plurality of output ports of output waveguides, arranged on the same surface as the input port of the input waveguide, and at least one dummy waveguide arranged abutting the outermost end of the output waveguides. An output port of the dummy waveguide is arranged on the same surface. The single optical-fiber block includes a plurality of ports corresponding to the input/output ports. The input/output ports are coupled in alignment with the input port of the input waveguide and the output ports of the output waveguides. The invention enables making a single processed alignment of the input/output ports of the planar lightguide circuit and the single input/output ports.