The Furukawa Electric Co., Ltd.

Toshihiko Baba

Tomofumi Kise

Masaki Funabashi

Noriyuki Yokouchi

Hitoshi Shimizu

Tatsuya Kimoto

Keishi Takaki

Suguru Imai

Masaki Funabshi

A surface-emitting laser apparatus includes: a surface-emitting laser element; and a driving apparatus supplying a modulation-driving current to the surface-emitting laser element. The modulation-driving current is intensity-modulated to vary across a value of a bias current. The number of lateral modes of laser oscillation of the surface-emitting laser element changes from one to three at maximum in accordance with a value of the modulation-driving current. Among changing currents at which number of the lateral modes of the laser oscillation of the surface-emitting laser element changes, if a first changing current is defined at which the number of the lateral mode of the laser oscillation changes from one to two, the driving apparatus supplies the modulation-driving current to the surface-emitting laser element. The modulation-driving current is set so that a value of the first changing current is not between the bias current and a maximum value of the modulation-driving current.

Surface-emitting laser apparatus, optical module, and method of driving surface-emitting laser element

An optical phase modulator includes a main Mach-Zehnder interferometer having first and second main optical waveguide path arms, whose initial phase difference in the used wavelength is &#x3c0;, a first sub Mach-Zehnder interferometer having first and second sub optical waveguide path arms that are formed in the first main optical waveguide path arm, whose initial phase difference in the used wavelength is 0, and a second sub Mach-Zehnder interferometer having third and fourth sub optical waveguide path arms that are formed in the second main optical waveguide path arm, and whose initial phase difference in the used wavelength is 0. Of each of the main optical waveguide path arms and the sub optical waveguide path arms, at least the portions where high-frequency electrodes are formed are constructed using semiconductor waveguide paths, and reduce the effects of frequency chirping caused by an orthogonal component due to light absorption in the semiconductor.

Optical phase modulator and optical phase modulating device

A surface emitting laser is provided with an upper reflecting mirror having a photonic crystal structure with a point defect at the center, and emits a laser beam from the side of a lower reflecting mirror. An upper electrode is formed on the point defect at the center, and element resistance is reduced. A material transparent to a wavelength of the laser beam is used for a substrate. The emission efficiency is improved by reducing the element resistance of the photonic crystal surface emitting laser.

Surface emitting semiconductor laser element

To provide a photonic crystal semiconductor device which enables various kinds of optical devices having a photonic crystal structure which is readily formed using a semiconductor and a semiconductor manufacturing process, and a manufacturing method thereof. The object can be achieved by a photonic crystal structure, including a lower DBR layer, a core layer, an upper DBR layer, and a dielectric multilayer filmwhich are sequentially laminated from an n-InP substrateside, a plurality of holesformed in the direction of a film thickness in the core layerand the upper DBR layer, and a line defect portionwith none of the plurality of holes formed therein and disposed between the plurality of holes, wherein the line defect portionserves as an optical waveguide.

Photonic crystal semiconductor device and production method thereof

A DFB semiconductor laser device includes a diffraction grating extending parallel to a laser cavity. The diffraction grating has ununiform structure wherein some of the corrugation patterns of diffraction grating are omitted periodically, the diffraction grating has different duty ratio between the area near the front facet of the laser cavity and the area near the rear facet, or the length of the diffraction grating is smaller than the cavity length and the width of the diffraction grating reduces in the vicinity of the rear end of the diffraction grating down to zero at the rear end.

DFB semiconductor laser device having ununiform arrangement of a diffraction grating

A DFB semiconductor laser device including an n-type semiconductor substrate and a layer structure, overlying the semiconductor substrate, including an active layer, a compound semiconductor layer constituting a diffraction grating and overlying the active layer, and an embedding layer embedding the diffraction grating, wherein said at least one of the compound semiconductor layer and the embedding layer has a carrier density of 7&#xd7;10to 2&#xd7;10cm.

Distributed feedback semiconductor laser device

A method for forming a set of DFB lasers includes the steps of forming active layers having different peak gain wavelengths, measuring the peak gain wavelengths of the active layers, and forming diffraction gratings having periods based on the measured peak gain wavelengths, the periods allowing the detuning amount of the DFB laser device to fall within a design value.

Growing community of inventors

Tokyo, Japan

Tomofumi Kise