The Furukawa Electric Co., Ltd.

Takeharu Yamaguchi

Akihiko Kasukawa

Yuichiro Irie

Toshikazu Mukaihara

Junji Yoshida

Noriyuki Yokouchi

Yutaka Ohki

Satoshi Arakawa

Nariaki Ikeda

Yoshihiro Shimada

Takeo Shimizu

Michio Ohkubo

Takahiro Sasaki

Etsuji Katayama

Kazuaki Nishikata

Nobumitsu Yamanaka

Toshiaki Tsuda

Hiroki Manabe

Toru Kagoura

Takao Ninomiya

Ryusuke Nakasaki

Hideo Aoyagi

Tatsuto Kurobe

Ocean floating installations () are disposed on the ocean. The ocean floating installations () float on the ocean with the lower part of the ocean floating installations () being fixed to the seabed by mooring ropes (). Each of the ocean floating installations () is connected at a connection part () to a cable (), which is a first cable. Each of the cables () is connected at a connection part () to a cable (), which is a second cable. In other words, the ocean floating installations () are connected to each other by the cables () and the cable (). A connection is established with the cables () at the connection parts () located on the seabed. In other words, the cables () are installed on the seabed.

Undersea cable, undersea cable installation structure, and method for installing undersea cable

An EA-DFB module including a DFB laser diode and an EA modulator formed on an InP first-conductivity-type substrate has a mesa stripe, a current blocking structure formed on both side surfaces of the mesa strip and a second InP cladding layer formed on top of the mesa stripe and the current blocking structure. The current blocking structure includes a Fe-doped semi-insulating film, a first conductivity-type buried layer and a carrier-depleted layer. The carrier-depleted layer reduces the parasitic capacitance at the boundary between the first-conductivity-type buried layer and the second InP cladding layer.

Optical device having a carrier-depleted layer

A monolithic semiconductor optical device with excellent temperature and modulation characteristics and associated method of manufacturing whereby the device has a semiconductor substrate, a semi-insulating buried heterostructure GaInAsP-based DFB laser; and either a buried ridge type AlGaInAs-based EA or a self aligned structure (SAS) AlGaInAs-based EA modulator.

Semiconductor optical device and method for fabricating same

A semiconductor laser device according to the present invention comprises a laminated structure of a semiconductor material including an active layer formed of a quantum well structure, a low-reflection film formed on one end face of the structure, and a high-reflection film formed on the other end face of the structure. The cavity length (L) of the device is 1,200 &mgr;m or more. This laser device, which enjoys high kink currents and a satisfactorily linear current-optical output characteristic, is a useful pumping light source for optical fiber amplifier.

Semiconductor laser device

A semiconductor laser device ( ) includes a layered structure formed on an n-type GaAs substrate ( ) having a bandgap energy Eg and including an n-type AlGaAs cladding layer ( ), an active layer ( ) including a quantum-well structure of two layers InGaAs/GaAs having a bandgap energy Eg which is smaller than Eg , a p-type AlGaAs cladding layer ( ), and a p-type GaAs cap layer ( ), which are consecutively epitaxially grown. The cap layer and the upper portion of the p-type cladding layer are formed as a stripe-shaped mesa structure. An SiN passivation film ( ) is formed on the areas except for the top of the cap layer. On the exposed cap layer and the passivation layer a p-side electrode ( ) is formed. On the bottom surface of the substrate an n-side electrode ( ) including layered metal films of In/AuGe/Ni/Au is formed. An absorption medium layer is interposed between the GaAs substrate and the n-side electrode.

Semiconductor laser

The present invention provides a semiconductor laser module. A semiconductor laser module ( A) comprising a semiconductor laser element ( ) and an optical fiber ( ) optically coupled by an optical coupling means ( ) is provided, wherein on the optical fiber ( ), a reflective portion ( ) and a birefringence fiber ( ) are provided, the birefringence fiber ( ) is provided at least from the incident end on the side of the optical coupling means ( ) to immediately before the reflective portion ( ), a connection portion ( ) is provided at least at one point in the longitudinal direction of the birefringence fiber ( ), and in the connection portion ( ), two eigen axes of X axes and Y axes are connected so that the eigen axes intersect each other at an established angle &thgr;.

Semiconductor laser module

A semiconductor light emitting device including a semiconductor substrate and an active layer having band gap energy smaller than that of the active layer, and the bottom surface of the semiconductor substrate opposite to the active layer is a photo diffused reflection surface having unevenness. The unevenness reduces an amount of reflection rays to enable the stable operation.

Semiconductor light emitting device

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.

Optical amplifier, light source module and optical system

A semiconductor laser module comprises a semiconductor laser having a front end facet from which output light is emitted, and an optical fiber on which the output light emitted from the semiconductor laser is incident, where the optical fiber has a light feedback portion for reflecting light at a predetermined wavelength. The semiconductor laser is accommodated in a package together with one end side of the optical fiber. The light feedback portion includes a first light feedback portion set at a predetermined reflection center wavelength for determining an oscillating wavelength of the semiconductor laser, and at least one second light feedback portion.

A waveguide-type variable-sensitivity semiconductor photodetector has a waveguide photodetector area and an optical attenuation area formed on an n-InP substrate. The optical attenuation area includes a GaInAs optical waveguide layer having a bandgap energy of 0.85 eV, a pair of upper and lower cladding layers each having a bandgap energy of 1.35 eV and an intermediate layer disposed at the heterojunction interface between the optical waveguide layer and the upper cladding layer and having a bandgap energy of 1.0 eV. A pile-up of halls at the heterojunction interface is prevented by the intermediate layer to improve the linearity of the output optical signal to the input optical signal.

Waveguide-type variable-sensitivity semiconductor photodetector

A waveguide type semiconductor photodetector device comprises a photosensitive section including a photo-absorption layer for converting a signal light into an electric signal, and an optical attenuation section including an optical attenuation layer made of a bulk crystal for attenuating incident light. Assuming that E.sub.g.ATT and E.sub.in are bandgap energy of the optical attenuation layer and optical energy of the incident light signal, respectively, E.sub.in +50 meV.ltoreq.E.sub.g,ATT .ltoreq.E.sub.in +100 meV holds. The optical absorption layer and the optical attenuation layer are made of GaInAs and GaInAsP, respectively, for adapting to incident light of a 1.55 mm wavelength.

Semiconductor photodetector having an optical attenuator

A surface emission semiconductor laser device has a semiconductor laminate mirror constituted of a plurality of pairs of InGaAS/InAlP films epitaxially grown on a GaAs or InGaAs substrate and a laser element bonded to the laminate mirror. The InAlP films of the laminate mirror are lattice-matched or not lattice-matched due to the amount of Al in the InAlP films. The laminate mirror has a high relative refractive index between the InGaAs and InAlP films and thus has a high reflectance to thereby improve the emission efficiency of the surface emission laser device.

Growing community of inventors

Tokyo, Japan

Takeharu Yamaguchi