Fujitsu Corporation

Fujitsu Optical Components Limited

Yoshio Sakai

Kazuyuki Mori

Yuji Tochio

Tamotsu Akashi

Atsuo Ishizuka

Takeshi Hoshida

Toshiki Tanaka

Yuichi Akiyama

Satoshi Ide

Yuji Ishii

A receiving device includes a light source outputting local oscillation light, a detector detecting intermittent input of a burst light signal by using the local oscillation light, a first converter converting the detected burst optical signal into an electrical analog signal, an amplifier amplifying the analog signal according to a gain, a second converter converting the amplified analog signal into a digital signal, and a setting processor setting the gain of the amplifier and a wavelength of the local oscillation light instructed by a control device when setting a communication line with one of transmitting devices transmitting the burst optical signal, wherein, before setting the communication line, the setting processor switches the wavelength of the local oscillation light according to the burst optical signal transmitted from each of the transmitting devices, adjusts the gain of the amplifier and notifies the control device of the adjusted gain.

Receiving device and receiving method

An optical communication system includes an optical transmitter, and an optical receiver connected via a transmission line to the optical transmitter, in which system the optical transmitter transmits a continuous-wave light signal that enables beat detection when combined with a local oscillator signal in the optical receiver, and the optical receiver acquires a beat waveform through digital sampling by detecting the light signal using the local oscillator signal, performs frequency analysis on digitally sampled data having the beat waveform prior to demodulation, and controls the local oscillator frequency based upon the beat frequency.

Optical communication system, optical transmitter, and optical receiver

An optical transmitter includes: an optical modulator including a first modulation unit and a second modulation unit respectively configured to propagate a first optical signal and a second optical signal that are obtained by splitting input light; a signal generator configured to generate a first drive signal and a second drive signal that are respectively supplied to the first modulation unit and the second modulation unit; a phase controller configured to control a phase difference between the first optical signal and the second optical signal in the optical modulator; and a phase difference detector configured to detect the phase difference between the first optical signal and the second optical signal controlled by the phase controller. The signal generator generates the first drive signal and the second drive signal based on the phase difference detected by the phase difference detector.

Optical transmitter and modulated optical signal generating method

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 optical switch includes a mirror to reflect an input light; a controller to generate a control signal representing a target rotation angle of the mirror; a generator to generate a low-frequency signal; an adder to superimpose the low-frequency signal on the control signal; a driver to drive the mirror with a drive voltage corresponding to the control signal on which the low-frequency signal is superimposed; a detector to detect a frequency component or a harmonic component of the low-frequency signal included in an output light reflected by the mirror; and a correction unit to correct the control signal based on the detection result by the detector. The generator determines an amplitude of the low-frequency signal according to the target rotation angle.

Optical switch and method for controlling optical switch

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

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.

Optical-switch testing apparatus, optical-signal switching apparatus, optical-switch testing method, and control method for optical-signal switching

A mirror controller of an optical switch comprises a signal generator () for passing the optical signal on the same light path as the one for optical communication using the optical switch, and an image analyzer () detecting the optical signal as the light scattered by at least one of tilt mirrors () and an output collimator array (). The image analyzer detects the position of the light beam image as a control position () based on the scattered light, and controls the tilt mirrors in such a manner that the detected control position coincides with the predetermined desired target position () on at least one of the tilt mirrors and the output collimator array. The mirror controller can realize the connection test of the optical signal between input and output with high accuracy and reliability.

Mirror controller for optical switch

A wavelength selective switch module is disclosed. The wavelength selective switch module includes: a unit for generating test light; a multiplexing unit for multiplexing the test light with the wavelength multiplexed light; a splitting unit for splitting the test light from output light of each of two output ports; a feedback control unit for obtaining deflection control amounts for the deflection unit corresponding to a wavelength of the test light such that a light level of the test light that is split from the output light output from each of the two output ports becomes maximum; and a calculation unit for calculating deflection control amounts for output ports other than the two output ports for the deflection unit for the test light and calculating deflection control amounts for output ports for deflection units of wavelengths included in the wavelength multiplexed light using the deflection control amounts for the deflection unit for the test light output from each of the two output ports by which the light level of the test light becomes maximum.

Wavelength selective switch module

An optical switch device is disclosed that includes an optical system deflecting and outputting input light signals using deflector parts; resistor parts provided in corresponding routes for feeding driving signals output from drivers to the corresponding deflector parts; a signal generator part generating a DC signal and an AC signal and feeding the DC and AC signals to the deflector parts through the corresponding drivers and the corresponding resistors; a threshold generator part generating a first threshold and a second threshold corresponding to the DC and AC signals, respectively; a voltage detector part detecting a voltage across each of the resistor parts; and a failure detector part determining whether the deflector parts are normal or out of order based on the corresponding results of comparing the voltages detected by the voltage detector part with at least one of the first threshold and the second threshold.

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Kawasaki, Japan

Yoshio Sakai