Abstract: In an optical transmitter in which the amount of light of an LD is monitored by a monitor PD, and the power of the LD is kept constant by feedback, the present invention aims to provide an optical transmitter that is suitable for size and cost reductions while being able to input a greater amount of the LD light of to the monitor PD, and that is capable of performing higher-bit-rate transmission. The present invention is characterized in that a concave groove is formed in a substrate, and the monitor photodiode is mounted on a slanted face of the concave groove, and the light of the LD that is oppositely and horizontally disposed is received directly by the monitor the LD photodiode.

Abstract: An optical switch that can restrain the occurrence of cross talk is provided. A first waveguide path 11 and a second waveguide path 12 are provided on a waveguide substrate PCL so as to intersect each other at a given angle. A trench T is formed in a straight line in the surface of the waveguide substrate PCL so as to cross the central axes of the first waveguide path and the second waveguide path. The trench T is as deep as to expose the whole end face of the first waveguide path and the second waveguide path. The first waveguide path 11 and the second waveguide path 12 are arranged such that their central axes are arranged asymmetrically with respect to the straight line.

Abstract: This invention relates to a diffraction grating device having a refractive index modulation formed in an optical waveguide region in a predetermined region in the longitudinal direction of the optical waveguide. In the diffraction grating device, a refractive index modulation is formed in the core region in a predetermined region in the longitudinal direction of the optical waveguide. In this diffraction grating device, the optical period of the refractive index modulation is substantially constant, the phase of the refractive index modulation is inverted at a phase inversion portion, and the number of phase inversion portions is one or two. In this diffraction grating device, the absolute value of a parameter R (equation (22a)) is smaller than 0.25. According to this invention, a diffraction grating device capable of shortening the region where the refractive index modulation is formed and flattening the reflectance characteristic in the reflection wavelength band is provided.

Abstract: A ferrule product 30b is utilized in an optical module 5 comprising a semiconductor optical amplifier 55 having a pair of end facets. The ferrule product 30b comprises an optical fiber 51 and a ferrule 52. The optical fiber 51 has one end part, optically coupled with one of the pair of end facets, a first part including a grating 511 disposed at a predetermined position separated from one end part, and a second part different from the first part. The ferrule 52 has a capillary part 521 for holding the optical fiber 51 and a flange part 522 for holding the capillary part. The flange part 522 is disposed on the second part.

Abstract: The present invention provides a fiber optic connector comprising a fiber pressing member and a substrate having a part A with multiple fiber arranging grooves in which bare portion of optical fibers are fixed, and a part B in which coated portion of optical fibers are fixed, and its manufacturing method. The connector enables to prevent an increase in transmission loss or breakage of the optical fibers by reducing the localized stress on the fibers from the rear end of the fiber pressing member and the rear end edge of the fiber arranging grooves.

Abstract: This invention relates to a diffraction grating device having a refractive index modulation formed in an optical waveguide region in a predetermined region in the longitudinal direction of the optical waveguide. In the diffraction grating device, a refractive index modulation is formed in the core region in a predetermined region in the longitudinal direction of the optical waveguide. In this diffraction grating device, the optical period of the refractive index modulation is substantially constant, the phase of the refractive index modulation is inverted at a phase inversion portion, and the number of phase inversion portions is one or two. In this diffraction grating device, the absolute value of a parameter R (equation (22a)) is smaller than 0.25. According to this invention, a diffraction grating device capable of shortening the region where the refractive index modulation is formed and flattening the reflectance characteristic in the reflection wavelength band is provided.

Abstract: A fiber grating laser module comprises a semiconductor optical amplifier and a grating fiber in which a Bragg grating is formed in the core. The semiconductor optical amplifier provides a wave guide in which the light is generated and amplified by the carrier injection, the light emitting facet and the light reflecting facet. The Bragg grating in the grating fiber and the light reflecting facet of the semiconductor amplifier forms an optical resonator. The subject of the invention is that the reflectance of the Bragg grating at the Bragg diffraction wavelength is greater than 60%.