Fujitsu Corporation

Yuji Miyaki

Kazuhiro Suzuki

Yoshinori Ohkuma

Kazuo Yamane

Masakazu Kishi

Michikazu Shima

Yasuhide Kuroda

Satoru Yamada

Shigeichi Izumi

Kenichiro Tsubone

Hiroshi Kuzukami

Yoshinori Nakane

Akihiko Yasuda

Tsukasa Takahashi

Takashi Tsuda

Yumiko Kawasaki

Yuji Tamura

Hiroyuki Itou

Yasunori Nagakubo

Setsuo Misaizu

Tetsuo Wada

Hisaya Sakamoto

Masakazu Mori

Norio Nagase

Keisuke Imai

Kazuhiro Hongo

An optical module which can achieve miniaturization, high performance and cost reduction is, provided. The optical module includes a photoelectric component, a high-speed signal processing part which processes a high-speed signal photoelectrically converted by the photoelectric component, and a low-speed signal processing part which processes a low-speed signal. The high-speed signal processing part and the low-speed signal processing part are overlapped with each other in a vertical direction and electrically connected to each other.

Optical module

The present invention aims at providing a drive circuit and a drive method for a semiconductor laser module including an electro-absorption type optical modulator, capable of obtaining a stable optical output without controlling a module temperature to be constant. To this end, the drive circuit of the present invention detects a temperature in the semiconductor laser module comprising a semiconductor laser and an EA modulator, and based on the detected temperature, controls a drive current supplied to the semiconductor laser and a bias voltage and a modulated electric signal applied to the EA modulator, so that average power, an extinction ratio and an optical cross point of an optical signal output from the semiconductor laser module are held to be constant.

Drive circuit and drive method of semiconductor laser module provided with electro-absorption type optical modulator

An optical module which can achieve miniaturization, high performance and cost reduction is provided. The optical module includes a photoelectric component, a high-speed signal processing part which processes a high-speed signal photoelectrically converted by the photoelectric component, and a low-speed signal processing part which processes a low-speed signal. The high-speed signal processing part and the low-speed signal processing part are overlapped with each other in a vertical direction and electrically connected to each other.

Optical Module

The control circuit for supplying a driving current to a laser diode makes it possible to keep the laser driving current variable in a wide range. The control circuit includes a laser diode, a photo diode for receiving a part of an optical output emitted from the laser diode and outputting an electrical signal corresponding to a level of the optical output, a first current supplying circuit for supplying a bias current to the laser diode, a first monitor circuit for monitoring a size of a signal driving current supplied by the first current supplying circuit, a second monitor circuit for monitoring a size of the bias current supplied by the second current supplying circuit, a first feed-back loop for controlling the signal driving current supplied from the first current supplying circuit by the output of the first monitor circuit, as a reference of the electric signal outputted from the photo diode corresponding to the level of the optical output emitted from the laser diode, a second feed-back loop for controlling the bias current supplied from the second current supplying circuit by the output of the second monitor circuit, as said reference of the signal outputted from the photo diode corresponding to the level of the optical output emitted form the laser diode; and an adder circuit for adding an offset current of the signal driving current supplied from the first current supplying circuit on the outside of the first feed-back loop.

Control circuit for supplying a driving current to a laser diode

The optical amplifier includes a doped fiber doped with a rare earth element, a pumping light source, means for introducing signal light and pumping light into the doped fiber, detection means for detecting whether or not amplified signal light is included in light outputted from the doped fiber, and means for decreasing the intensity of the pumping light when it is detected that amplified signal light is not included. It can be possible to eliminate an influence of an optical surge arising from a characteristic of the doped fiber.

Optical amplifier and optical transmission apparatus

A light receipt system has a bias circuit and a light-receipt element. The bias circuit controls light input power to the light-receipt element to the optimum multiplication factor. The bias circuit of the light-receipt element has a first resistor, a second resistor, and a third resistor. The first resistor and the second resistor are connected in parallel, and the light-receipt element is connected between a connection of the first resistor and the second resistor, and the third resistor. A bypass current path is provided, connected to a junction point between the first resistor and the second resistor.

Light-receipt system with current bias circuit and pre-amplifier for use

A drive circuit drives an electronic device that converts electric power into light or heat energy. The drive circuit has a switch connected to the electronic device in series, and a control circuit for providing, in response to an input control signal, a pulse modulation signal for controlling the switch. The frequency of the pulse modulation signal is higher than the response frequency of the electronic device. Alternatively, the drive circuit may have first to fourth switches disposed on both sides of the electronic device, for passing a current in different directions through the electronic device, and a control circuit for controlling the switches to change the direction and magnitude of the average of the current flowing through the electronic device in response to an input control signal.

Drive circuit for electronic device

Slice amplifier using FET's

Growing community of inventors

Kawasaki, Japan

Yuji Miyaki