Abstract: An optical device includes an optical amplifier that optically amplifies incident light, a first isolator that is arranged on an input stage of the optical amplifier and inputs the incident light to the optical amplifier, and a second isolator that is arranged on an output stage of the optical amplifier and receives input of incident light that has been optically amplified by the optical amplifier. The first isolator inputs, to the optical amplifier, first linearly-polarized incident light that is converted from randomly-polarized incident light and that has been transmitted. The second isolator, when reflected light of the first linearly-polarized incident light that has been optically amplified by the optical amplifier is input from a reverse direction, converts reflected light of the first linearly-polarized incident light to reflected light of second linearly-polarized light that is orthogonal to the reflected light of the first linearly-polarized incident light.

Abstract: An optical transmission module includes a photonic integrated circuit, a processor that controls the power state of the photonic integrated circuit, and a current source circuit that supplies electric current to a light source used for the photonic integrated circuit. The photonic integrated circuit has an optical multiplexer block including a plurality of multiplexers connected in a n-level tree structure (n is an integer greater than 1), 2{circumflex over (?)}n optical modulators connected to inputs of the optical multiplexer block, and a photodetector connected to an input or an output of each of the plurality of the multiplexers. The light source emits a light beam to be incident onto a corresponding one of the 2{circumflex over (?)}n optical multiplexers. The processor controls the current source circuit for each of the plurality of the multiplexers, based on the monitored value acquired from the photodetector provided to each of the plurality of the multiplexers.

Abstract: An optical module includes: a first board having an optical component bonded thereto with an adhesive; a connection structure part rising from the first board and made of a material having lower thermal conductivity than thermal conductivity of a material of the first board; and a second board joined to the connection structure part.

Abstract: An optical module includes: a board that is accommodated in a housing and in which a through hole is formed; a metal plate that is bonded to an area of the board including the through hole; a component that is mounted on one surface of the metal plate and is arranged inside the through hole; and a thermal-conductive member that is arranged on another surface of the metal plate and transmits heat generated by the component to the housing.

Abstract: An optical module includes: a board that is accommodated in a housing and in which a through hole is formed; a metal plate that is bonded to an area of the board including the through hole; a component that is mounted on one surface of the metal plate and is arranged inside the through hole; and a thermal-conductive member that is arranged on another surface of the metal plate and transmits heat generated by the component to the housing.

Abstract: An optical module includes: a first board having an optical component bonded thereto with an adhesive; a connection structure part rising from the first board and made of a material having lower thermal conductivity than thermal conductivity of a material of the first board; and a second board joined to the connection structure part.

Abstract: An optical transmission module includes: a bias current drive circuit to drive a bias current of a light-emitting element, on a basis of an input bias current setting value; a modulation current drive circuit to drive a modulation current of the light-emitting element, on a basis of an input modulation current setting value; a light-receiving element to measure an optical output power of the light-emitting element; a determiner to determine whether a difference between a target value of the optical output power and the optical output power measured by the light-receiving element is equal to or more than a threshold; and a controller configured to perform a correction control to the bias current drive circuit so that the bias current is reduced in accordance with the difference, when it is determined that the difference is equal to or more than the threshold by the determiner.

Abstract: An optical transmission module includes: a bias current drive circuit to drive a bias current of a light-emitting element, on a basis of an input bias current setting value; a modulation current drive circuit to drive a modulation current of the light-emitting element, on a basis of an input modulation current setting value; a light-receiving element to measure an optical output power of the light-emitting element; a determiner to determine whether a difference between a target value of the optical output power and the optical output power measured by the light-receiving element is equal to or more than a threshold; and a controller configured to perform a correction control to the bias current drive circuit so that the bias current is reduced in accordance with the difference, when it is determined that the difference is equal to or more than the threshold by the determiner.

Abstract: A light source module includes a single light source with two opposite light outputting faces, a first optical amplifier and a second optical amplifier provided on opposite sides of the light source adjacent to the corresponding light outputting faces, and a first monitor configured to monitor an output of the first optical amplifier, wherein a power output level of the first optical amplifier is controlled independently from the second optical amplifier based upon a monitoring result of the first monitor.

Abstract: A light source module includes a single light source with two opposite light outputting faces, a first optical amplifier and a second optical amplifier provided on opposite sides of the light source adjacent to the corresponding light outputting faces, and a first monitor configured to monitor an output of the first optical amplifier, wherein a power output level of the first optical amplifier is controlled independently from the second optical amplifier based upon a monitoring result of the first monitor.

Abstract: An optical transmission module includes a bias current driver circuit adapted to input bias current set in response to a temperature of a laser diode to the laser diode, a modulation current driver circuit adapted to input modulation current set in response to the temperature of the laser diode to the laser diode, and a decision circuit adapted to decide whether or not an error of optical output power of the laser diode detected by a light reception device with respect to a target value of the optical output power of the laser diode at the set bias current and the set modulation current is equal to or higher than a threshold value. The modulation current driver circuit inputs, while the error is equal to or higher than the threshold value, correction modulation current higher than the set modulation current to the laser diode.

Abstract: A communication module includes a communication circuit, a connector coupled to the communication circuit, a housing having a space for arranging the communication circuit and an aperture for arranging the connector, and a projection provided at facing inside wall surface of the housing and attenuating an electromagnetic wave within a frequency range transmitted in the space.

Abstract: An optical transmission module includes a bias current driver circuit adapted to input bias current set in response to a temperature of a laser diode to the laser diode, a modulation current driver circuit adapted to input modulation current set in response to the temperature of the laser diode to the laser diode, and a decision circuit adapted to decide whether or not an error of optical output power of the laser diode detected by a light reception device with respect to a target value of the optical output power of the laser diode at the set bias current and the set modulation current is equal to or higher than a threshold value. The modulation current driver circuit inputs, while the error is equal to or higher than the threshold value, correction modulation current higher than the set modulation current to the laser diode.

Abstract: The present invention has an object to provide an optical device capable of leading out a light propagated through an optical waveguide to a desired substrate side face while maintaining the sufficient power of the light, within a range of limited substrate size. To this end, according to the optical device of the present invention, a groove is formed in the vicinity of an end portion on the optical output side of the optical waveguide, on the substrate on which the optical waveguide is formed, a side wall of the groove is used as a reflecting plane, the light output from the optical waveguide is reflected by the reflecting plane, and the reflected light is emitted from the desired substrate side face.

Abstract: The present invention has an object to provide an optical device capable of leading out a light propagated through an optical waveguide to a desired substrate side face while maintaining the sufficient power of the light, within a range of limited substrate size. To this end, according to the optical device of the present invention, a groove is formed in the vicinity of an end portion on the optical output side of the optical waveguide, on the substrate on which the optical waveguide is formed, a side wall of the groove is used as a reflecting plane, the light output from the optical waveguide is reflected by the reflecting plane, and the reflected light is emitted from the desired substrate side face.

Abstract: The present invention has an object to provide an optical device capable of leading out a light propagated through an optical waveguide to a desired substrate side face while maintaining the sufficient power of the light, within a range of limited substrate size. To this end, according to the optical device of the present invention, a groove is formed in the vicinity of an end portion on the optical output side of the optical waveguide, on the substrate on which the optical waveguide is formed, a side wall of the groove is used as a reflecting plane, the light output from the optical waveguide is reflected by the reflecting plane, and the reflected light is emitted from the desired substrate side face.

Abstract: The invention provides an optical modulator wherein appearance of radiation mode light can be suppressed to improve performances as a device. The optical modulator includes a multiplexing waveguide which in turn includes two input waveguides to which propagation lights from a linear waveguide are inputted, a waveguide coupling element, and two output waveguides. The width of the waveguide coupling element on the input side is greater than the total width of the two input waveguides, and the width of the waveguide coupling element on the output side is greater than the total width of the two output waveguides. The device of the present invention is applied typically to an optical communication system.

Abstract: The invention provides an optical modulator wherein appearance of radiation mode light can be suppressed to improve performances as a device. The optical modulator includes a multiplexing waveguide which in turn includes two input waveguides to which propagation lights from a linear waveguide are inputted, a waveguide coupling element, and two output waveguides. The width of the waveguide coupling element on the input side is greater than the total width of the two input waveguides, and the width of the waveguide coupling element on the output side is greater than the total width of the two output waveguides. The device of the present invention is applied typically to an optical communication system.

Abstract: The invention provides an optical modulator wherein appearance of radiation mode light can be suppressed to improve performances as a device. The optical modulator includes a multiplexing waveguide which in turn includes two input waveguides to which propagation lights from a linear waveguide are inputted, a waveguide coupling element, and two output waveguides. The width of the waveguide coupling element on the input side is greater than the total width of the two input waveguides, and the width of the waveguide coupling element on the output side is greater than the total width of the two output waveguides. The device of the present invention is applied typically to an optical communication system.

Abstract: The invention provides an optical modulator wherein appearance of radiation mode light can be suppressed to improve performances as a device. The optical modulator includes a multiplexing waveguide which in turn includes two input waveguides to which propagation lights from a linear waveguide are inputted, a waveguide coupling element, and two output waveguides. The width of the waveguide coupling element on the input side is greater than the total width of the two input waveguides, and the width of the waveguide coupling element on the output side is greater than the total width of the two output waveguides. The device of the present invention is applied typically to an optical communication system.