Nippon Telegraph and Telephone Corporation

Ntt Electronics Corporation

Toshihide Yoshimatsu

Atsushi Kanda

Masahiro Nada

Fumito Nakajima

Yasuhiko Nakanishi

Hidehiko Takara

Takayuki Kobayashi

Seigo Ando

Yuki Yamada

Tadao Ishibashi

Kazushige Yonenaga

Shigeru Kanazawa

Yoshifumi Muramoto

Yoshiho Maeda

Yukio Tsukishima

Masahiko Jinno

Haruki Yokoyama

Kozicki Bartlomiej

A highly efficient optical burst transmitter is provided. An embodiment is an optical burst transmitter including a control circuit configured to output a data signal and a burst control signal and a semiconductor optical amplifier configured to output an optical data signal modulated using the data signal as an optical burst data signal controlled using the burst control signal, the optical burst transmitter including: an electric line configured to connect the control circuit and the semiconductor optical amplifier and transmit the burst control signal; and an impedance matching circuit configured to impedance-match a characteristic impedance of the electric line and the semiconductor optical amplifier with each other.

Optical burst transmitter

In an optical receiver circuit which suppresses an unnecessary increase in impedance and occurrences of resonance and radiation noise and which produces preferable high-frequency transmission characteristics, a PD submount mounted with a PD chip and a chip capacitor and a TIA carrier mounted with a TIA chip are electrically connected to each other by a bonding wire. The chip includes an anode electrode pad and a cathode electrode pad, anode electrode-side ground pads are formed at positions that sandwich the pad, and cathode electrode-side ground pads are formed at positions that sandwich the pad. A wire electrically connects the pad and a signal pad for input of the chip to each other, a wire electrically connects the pad and the capacitor to each other, and a wire electrically connects the pads and the pads to each other.

Optical receiving circuit

Provided is a semiconductor light receiving element which can achieve a high-speed operation without sacrificing light receiving sensitivity while increasing the margin of a manufacturing process. The semiconductor light receiving element according to the present invention is characterized by comprising: a semiconductor layer doped with a first impurity; a semiconductor light absorption layer in which a band gap energy is adjusted to absorb incident light on the semiconductor layer doped with the first impurity; a semiconductor layer on the semiconductor light absorption layer and doped with a second impurity; and a metal electrode contacting side surfaces of the semiconductor layer doped with the second impurity, wherein side surfaces of the metal electrode are surfaces parallel to a growth direction of the semiconductor layer doped with the second impurity.

Semiconductor light receiving element

The misalignment between light reception lenses and light reception elements in a lens integrated light reception element for converting a plurality of optical signals with different wavelengths into electric signals is easily inspected. The lens integrated light reception element includes one or more light reception lenses that receive the optical signals, one or more light reception elements each disposed on a main axis of the light reception lens and converting the optical signal into the electric signal, one or more inspection pinholes through which illumination light passes, and one or more inspection lenses each including a main axis parallel to the main axis of the light reception lens and converging the illumination light having passed through the inspection pinhole.

Lens-integrated light-receiving element and method of examining same

A layer in which the potential level difference normally unrequired for device operation is generated is positively inserted in a device structure. The potential level difference has such a function that even if a semiconductor having a small bandgap is exposed on a mesa side surface, a potential drop amount of the portion is suppressed, and a leakage current inconvenient for device operation can be reduced. This effect can be commonly obtained for a heterostructure bipolar transistor, a photodiode, an electroabsorption modulator, and so on. In the photodiode, since the leakage current is alleviated, the device size can be reduced, so that in addition to improvement of operating speed with a reduction in series resistance, it is advantageous that the device can be densely disposed in an array.

Semiconductor device

A bandwidth variable communication apparatus includes: a route exchange unit including a route exchange function for switching an output port of a stream signal of one or more wavelengths input from an input port based on both or a part of wavelength and time, and including a bandwidth change function for changing passable frequency bandwidth in a section from the input port to the output port through which the stream signal passes; and a control unit including a control information transmit-receive function for transmitting and receiving control information for both or a part of the route exchange function and the bandwidth change function of the route exchange unit, and including a control function for controlling the route exchange unit based on the control information. All or a part of the input ports and the output ports are connected to other communication apparatuses via transmission routes.

Bandwidth variable communication apparatus and bandwidth variable communication method

Growing community of inventors

Musashino, Japan

Toshihide Yoshimatsu