Fujitsu Corporation

Fujitsu Optical Components Limited

Kazuyuki Mori

Yuji Tochio

Yoshio Sakai

Satoshi Ide

Yuji Ishii

Atsuo Ishizuka

Takashi Shimizu

Tamotsu Akashi

Tetsuji Yamabana

Yukito Tsunoda

Shinji Yamashita

Koji Terada

Hiroyuki Nobuhara

Toru Matsuyama

Yoshihiro Saito

Norio Nagase

Kenji Rikimaru

Kenichi Nakamoto

Hiromasa Tanaka

Kakuji Inoue

Tadashi Ikeuchi

Yo Akimoto

Tsuyoshi Yamamoto

Kohei Shibata

Kazuhiro Tanaka

Ichiro Watanabe

Nobuhiro Fujimoto

Shinichi Sakuramoto

Hisako Watanabe

Ken-ichi Nakamoto

Yoshihisa Kondo

Kiyomi Narita

Kensuke Takahashi

A first header-attaching unit attaches to data of a low speed bit rate A, a header of the bit rate A. A second header-attaching unit attaches the header of the bit rate A to data of a high speed bit rate B. A combining unit combines outputs of the first and the second header-attaching units. A low speed scrambling unit performs a scrambling process on combined data by using a clock corresponding to the bit rate A. A high speed scrambling unit performs a scrambling process on the data of the bit rate B by using a clock corresponding to the bit rate B. During a timing corresponding to the bit rate A in the frame, a selector selects an output of the low speed scrambling unit. During a timing corresponding to the bit rate B in the frame, the selector selects an output of the high speed scrambling unit.

Optical transmission device, scrambling method, and descrambling method

An output control unit outputs data of bit rate A to a first header-attaching unit and data of bit rate B to a second header-attaching unit. An instructing unit instructs the first or the second header-attaching unit to attach a header of bit rate being the least bit rate to the data of bit rate A or B. The first header-attaching unit creates a header of bit rate A, including an ID of a destination ONU of the data of bit rate A and information concerning the data length, and attaches the header of bit rate A to the data of bit rate A. The second header-attaching unit creates a header of bit rate A, including an ID of the destination ONU of the data of bit rate B and information concerning the data length, and attaches the header of bit rate A to the data of bit rate B.

Optical transmission device and optical transmission method

In an optical transmission apparatus, a light-emitting laser varies its output wavelength when applied with a wavelength control signal for switching wavelengths. A wavelength controller outputs the wavelength control signal, and a filter unit subjects the wavelength control signal to a filtering process to remove high-frequency noise superimposed on the wavelength control signal. The filter unit stops the filtering process during the wavelength control and executes the filtering process during the operation.

Optical transmission apparatus and method

A communication terminal apparatus receives a management signal at a bit rate A and a data signal at a bit rate B (B=A&#xd7;M) through the same line. The communication terminal apparatus includes a signal regenerating unit, a management signal converting unit, a timing control unit, and a data signal obtaining unit. The signal regenerating unit regenerates a signal transmitted through the line as a signal of a bit rate C (C=A&#xd7;N). The management signal converting unit converts N bits of the regenerated signal into the management signal of one bit. The timing control unit controls timing for obtaining a data signal based on the management signal. The data signal obtaining unit obtains the data signal according to timing control of the timing control unit.

Communication terminal apparatus, communication apparatus, and signal receiving method

An optical communication apparatus includes a receiver configured to receive an optical signal transmitted from an optical transmitting apparatus; a detector configured to detect a predetermined pattern signal included in the optical signal; a calculator configured to calculate, based on a waveform of the predetermined pattern signal, an amount of dispersion of the predetermined pattern signal; and a compensator configured to compensate for dispersion according to the amount of dispersion.

Optical communication apparatus and optical communication method

In an optical receiver, a light receiving element receives the optical packet signals and converts the optical packet signals to electrical signals. A bias voltage supply section supplies bias voltage to the light receiving element. A monitoring section monitors an input level of each optical packet signal or each electrical signal and transmits a monitored value to the bias voltage supply section. In addition, the bias voltage supply section temporarily increases the bias voltage according to magnitude of the monitored value after an end of receiving of each optical packet signal.

Optical receiver

A demodulator includes: a splitter that branches a differential phase shift keying optical signal into a first branched optical signal passing through a first optical path and a second branched optical signal passing through a second optical path; a multiplexer that multiplexes the first branched optical signal having passed through the first optical path and the second branched optical signal having passed through the second optical path and makes interference between the first branched optical signal and the second branched optical signal; and a double refraction medium that reduces difference between phase differences between each polarized wave between the first branched optical signal and the second branched optical signal multiplexed by the multiplexer.

Demodulator and receiving device

In an optical switch controller, in order that residual vibration at movement control of a movable body such as a tilt mirror can be reduced and controlled with high accuracy, a processing unit outputs a driving signal for controlling the angle of the tilt mirror, the driving signal is D/A converted by a D/A converter and then is changed to a high-voltage signal by a high-voltage amplifier to be supplied to the tilt mirror, the electrostatic capacity of the tilt mirror changes corresponding to angle change of the tilt mirror, a mirror-angle detecting unit detects the electrostatic capacity and feeds back it as a correction value to a processing unit, and the processing unit corrects the driving signal using a correction value obtained when the angle of the tilt mirror is actually changed.

Optical switch controller and movable body controller

A control section of an optical switch calculates information relating to a polarization amount in an insulating film at each predetermined time, to update the information relating to the polarization amount in the insulating film. On the other hand, when a drive voltage is applied to a MEMS mirror, an initial value of the drive voltage corresponding to an input setting command is read out from an initial value memory, and also, the information relating to the polarization amount in the insulating film is read out from the polarization amount memory, and the initial value of the drive voltage is corrected according to the read information relating to the polarization amount in the insulating film, to thereby set a new drive voltage, and the new drive voltage is applied on electrodes of the MEMS mirror.

Optical switch and control method of optical switch, and control method of MEMS device

A wavelength locker includes: a birefringent plate for separating light emitted from a light source into two beams of light which are approximately in parallel to each other; a first light receiving element for directly receiving one of the two beams of light separated by the birefringent plate; a &#x3bb;/4 plate and an etalon filter through which other one of the two beams of light separated by the birefringent plate passes; and a second light receiving element for receiving the other one of the two beams of light which has passed through the etalon filter. The &#x3bb;/4 plate has an optic axis tilted at 45 degrees with respect to a polarization direction of light incident on the &#x3bb;/4 plate, changes a polarization direction of light, which has been reflected by the etalon filter and incident on the &#x3bb;/4 plate, such that the reflected light does not return to the light source after passing through the birefringent plate, and emits the resultant light.

Wavelength locker

Regarding the passive optical network (PON) system of the present invention, in an OLT, data of different bit rates is framed, and framed data rows are subjected to FEC encoding processing without changing the line up of the data, and a check bit is added to the end of the frame, and an optical signal that has been modulated in accordance with the data row to which the check bit has been added is transmitted to the optical transmission line. Then in an ONU that corresponds to a high speed bit rate to which an optical signal from the OLT has been applied via a power splitter, forward error correction of the reception data is performed. As a result in a PON system in which data of different bit rates coexist, the minimum reception rate of a high speed ONU can be improved without having an influence on a low speed ONU.

Passive optical network system and method of data transmission in the passive optical network

The present invention relates to a multi-bit-rate optical communication method, optical network units, and an optical line terminal that enable multi-bit-rate transmission of low bit-rate data and high bit-rate data while maintaining compatibility with existing systems and reducing upgrade costs of optical network units and labor required for the upgrade, wherein the optical line terminal transmits a first data area including frame synchronization information in a predetermined frame format at a first bit rate and a second data area at a second bit rate which is the first bit rate&#xd7;M(M&#x3e;1), and any of the optical network units performs reception processing at a rate once every M-bit to detect the frame synchronization information in the first data area and, based on detection timing thereof, performs reception processing of the second data area by a bit.

Multi-bit-rate optical communication method, optical network unit, and optical line terminal

A light source supplies optical signal to an optical switch and a detector detects light receiving level. A control unit changes a deflection control amount for changing an angle of a tilt mirror, and outputs the deflection control amount to a driving unit. When an input and an output ports are same, optical offset of the tilt mirror is calculated based on optimal angle at which the light detector detects an optimal point of the light receiving level. Whenever the input and the output port are different, a structure parameter of the tilt mirror is calculated based on the optical offset and the optimal angle. The optical offset and the structure parameter are stored in a memory as a test result.

Growing community of inventors

Kawasaki, Japan

Kazuyuki Mori