Fujitsu Corporation

Fujitsu Optical Components Limited

Fujitsu Quantum Devices Limited

Manabu Komiyama

Tetsuo Ishizaka

Saeko Yokoi

Shunichi Sato

Toshio Ohya

Noboru Sonetsuji

Takashi Tsuda

Noriaki Mizuguchi

Takashi Yamane

Yasunori Nagakubo

Shunichi Satoh

Tatsuro Kunikane

Takayuki Masuko

Toshiya Kishida

Yoshimitsu Sakai

Toshio Higashi

Masaki Kuribayashi

Tohru Watanabe

An optical transmitter includes a laser configured to emit light, a power of the light increasing with temperature decreasing, a Faraday rotator configured to rotate a polarization direction of the light in accordance with the temperature, and a first polarizer that has a principal axis inclined at a given angle and inputs the light output from the Faraday rotator.

Optical transmitter and optical transmission apparatus

An optical module comprises a splitting element that splits light outputted from a light source; a first monitoring means that detects the intensity of light split by the splitting element; a polarization control means that switches the polarization state of light outputted from the splitting element based on a control signal; a filter means that accepts light outputted by the polarization control means as input, and whereof the characteristic changes depending on the polarization state of the input light; and a second monitoring means that detects the intensity of the light transmitted through the filter means.

Optical module with built-in wavelength locker

Light incident on an input optical fiber is separated into p-polarized light and s-polarized light by a birefringent crystal. A voltage to be applied to a liquid crystal element having electrodes associated with the ray axes of the polarized light waves is controlled in order to convert the p-polarized light into s-polarized so that both the polarized light waves will be s-polarized light. A polarized-wave separation film transmits p-polarized light and reflects s-polarized light. When both the polarized light waves propagated through the liquid crystal element are s-polarized light, the light reflected from the polarized-wave separation film is reflected from a total-reflection film, and reflected again from the polarized-wave separation film. The resultant light falls on the birefringent crystal again via the liquid crystal element, and is restored to non-polarized light by the birefringent crystal. The non-polarized light then falls on a first output optical fiber.

Optical switch device

A package for hermetically sealing a semiconductor laser which outputs light having a wavelength of 1.1 &#x3bc;m or more is filled with a gas containing an oxidizing gas such as oxygen or ozone. The oxidizing gas in the package oxidizes hydrogen in the package to prevent hydrogen embrittlement of electrodes that applies stress on electrodes and to suppress variation in the emission wavelength which would otherwise result from the application of stress.

Optical semiconductor device

Disclosed herein is a laser diode module having a thermoelectric cooling element, a laser diode, and a thermistor in a housing. The thermoelectric cooling element has a first surface and a second surface between which heat exchange is performed. The first surface is in close contact with an inner surface of the housing. A base is provided on the second surface in close contact therewith. A laser carrier and a thermistor carrier are provided on the base in close contact therewith. The laser diode and the thermistor are provided on the laser carrier and the thermistor carrier in close contact therewith, respectively. A portion of the base in the vicinity of the laser carrier is thermally connected to the housing by a metal plate, for example, thereby allowing high-precision temperature control of the laser diode.

Laser diode module

An optical module includes a first level detecting part having a semi-transparent structure and receiving a light signal emitted from a light-emitting element, a second level detecting part receiving the light signal which penetrates through the first level detecting part and passes through an optical filter, and a control part controlling an operation temperature of the light-emitting element on the basis of electric signals output from the first and second level detecting parts.

Optical module

A Peltier control circuit detects a temperature of a device combined with a Peltier device and controls a current flowing through the Peltier device so as to keep the temperature of the device at a predetermined value. The circuit has a temperature sensing section for detecting the temperature of a device, a comparing section for comparing a temperature detection value with a predetermined temperature reference value, a limiting section for providing a comparison output with the limitation of a current flowing through the Peltier device and providing the limitation with a predetermined temperature characteristics, and a driving section for providing the Peltier device with an input or output driving current in accordance with the comparison output via the limiting section.

Peltier control circuit and a peltier device structure

An optical isolator has a low-profile construction. Two rod-like permanent magnets are on two sides of a Faraday element in parallel to an optical axis. The two permanent magnets are sandwiched and fixed between two ferromagnetic frames each having a light path hole therein. The ferromagnetic frames are each provided with a protrusion for guiding the magnetic flux generated by the permanent magnets to the Faraday element.

Optical isolator, faraday rotator suitable for use in the same, and

A semiconductor laser module includes a semiconductor laser assembly formed by containing a semiconductor laser in a package, a lens assembly fixed by welding to the package of the semiconductor laser assembly, and a fiber assembly fixed by welding to the lens assembly. The semiconductor laser assembly includes a base fixed to the package and a carrier fixed to the base. The semiconductor laser is mounted on the carrier. A lens holder of the lens assembly is spot-welded to the package at a plurality of positions set below the upper surface of the base.

Growing community of inventors

Kawasaki, Japan

Manabu Komiyama