Fujitsu Corporation

Fujitsu Optical Components Limited

Toru Matsuyama

Makoto Miki

Tadashi Ikeuchi

Tadao Inoue

Norio Ueno

Toshiyuki Takauji

Satoshi Ide

Norio Murakami

Shinichi Sakuramoto

Kazuyuki Mori

Hiroyuki Rokugawa

Masaaki Kawai

Yukito Tsunoda

Ryou Okabe

Masakazu Horishita

Hiroki Kanesaka

Kensuke Takahashi

An optical transmission apparatus and an optical transmission method are provided. In particular, an optical transmission apparatus is disclosed as being configured to add strength to a signal. The signal corresponds to a value that an input signal has, and the strength added to the signal is strength according to the value. The optical transmission apparatus is further configured to give delays to a plurality of signals that includes the signal and to convert the sum of the plurality of signals into an optical signal.

Optical transmission apparatus and method

An optical communication method includes outputting an optical data signal in which a signal amplitude of a non-data area that is an area other than a data area is made higher than a signal amplitude of the data area, to a predetermined receiver, receiving an optical input including the optical data signal with the predetermined receiver, detecting each of the signal amplitude of the non-data area and the signal amplitude of the data area of the optical input, creating a threshold for encoding the data area based on the signal amplitude of the data area, determining whether the optical data signal is received, based on the signal amplitude of the non-data area, and outputting a data signal in which the data area is encoded by using the threshold of the optical data signal, when it is determined that the optical data signal is received.

Method, system, and apparatus for optical communication

A power-saving mode flag generating unitsets a power-saving mode flag to active (non power-saving mode, turning on the power-source) when it receives a reset signal from a MAC unit. Furthermore, the power-saving mode flag generating unitsets the power-saving mode flag to sleep (power-saving mode, turning off the power source) in accordance with a signal-interrupt detection signal obtained by the signal-interrupt detecting unitof the packet monitoring unit. Depending on the state of a packet, the power-saving mode flag generating unitchanges the power-saving mode flag to active or sleep for the data communication area of the packet; however, for the ranging area of the packet, the power-saving mode flag generating unitalways sets the power-saving mode flag to active. A pattern discriminating unitdiscriminates between the data communication area and the ranging area of the packet.

Optical communication device and power-saving control method of optical communication device

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

An optical transmission apparatus communicable with a plurality of subscriber including a delay measuring part for detecting a response delay time from each subscriber based on reception timing of the delay measurement response optical packet, a detection part for detecting a received optical level of the delay measurement response optical packet received by the reception part and a state determination part for determining quality of an optical transmission state between the optical transmission apparatus and each subscriber based on the received optical level of the delay measurement response optical packet of each of the plurality of subscribers.

Optical transmission apparatus, subscriber apparatus and optical communication system

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

Using a switching signal from a coarse/fine switching and operation mode switching circuit, the width of change of a counter control value during power up is increased, and the width of change is reduced once a steady state is reached. In the steady state, the frequency of updating is limited by a control signal from an update permit control circuit. In the steady state, the frequency band of a current source in an LD driving circuit is reduced in width.

Light output control circuit

A receiving apparatus comprises a first waveform degradation compensating unit, a second waveform degradation compensating unit, a received waveform measuring unit for measuring waveform data on a received signal, a control unit for controlling compensation characteristics of the first and second waveform degradation compensating units to minimize a difference between frequency data obtained by converting the obtained received waveform data into a frequency domain and frequency data on a reference waveform free from waveform degradation, and time-constant generating units for making a difference in compensation characteristic control speed between the first and second waveform degradation compensating units. This realizes high-accuracy compensation for waveform degradation of a received signal stemming from chromatic dispersion, polarization mode dispersion or the like without employing a dispersion compensation fiber or a polarization maintaining fiber.

Receiving apparatus with waveform degradation compensating function

Light output control device

A circuit for controlling pulse width of a signal for driving a light emitting element, includes a pulse width control circuit capable of responding to multi-bit rates in the same circuit structure. For this purpose, the pulse width control circuit has a Tr/Tf control section controlling at least one of a rise time Tr and a fall time Tf of an input signal according to the bit rate of the input signal; a waveform shaping section shaping a signal output from the Tr/Tf control section to generate an output signal; and a control signal generating section generating a control signal for controlling an operation of the Tr/Tf control section based on pulse width control information.

Pulse width control circuit controlling pulse width of output light

The present invention alms at providing a low cost optical transmitter capable of controlling, with a high precision, fluctuations in optical output characteristic of a semiconductor light emitting device such as due to a temperature change. To this end, the optical transmitter of the present invention is constituted to comprise; a semiconductor light emitting device; a driving circuit for supplying a driving current to the semiconductor light emitting device; an optical output detecting section for detecting an optical output power of the semiconductor light emitting device; a storing section for storing temperature characteristic information including temperature characteristic data concerning the driving current to be supplied to the semiconductor light emitting device and temperature characteristic data concerning the optical output detecting section; a temperature detecting section for detecting temperature; and a controlling section for controlling the operation of the driving circuit, based on the temperature characteristic information read out from the storing section corresponding to the temperature detected by the temperature detecting section and based on the detection result of the optical output detecting section.

Optical transmitter provided with optical output control function

A light output control circuit to update light output synchronously with input data in burst signal transmission system is disclosed. The circuit has a function of issuing light deterioration warning unerringly, which includes: a monitoring portion to detect light output emitted from a light emission element driven in accordance with transmission data; a level comparator to compare a monitoring signal outputted from the monitoring portion with a reference signal; a data detection portion to detect the existence of the transmission data; and an output controller to determine whether a light output deterioration warning is to be issued using an output signal of the data detection portion and an output signal of the level comparator.

Light output control circuit with a warning function of deteriorated light output

An optical transmitter circuit including a light receiving element, such as a photodiode, which monitors the optical output of a light emitting element such as a semiconductor laser. A current-voltage converting circuit supplies a drive current from a drive circuit to the light emitting element and converts the output voltage of the light receiving element into voltage. An APC amplifier compares the converted output signals and a reference signal, and a hold circuit holds the output signal of the APC amplifier and uses the output signal as a current control signal of the drive circuit. A &ldquo;1&rdquo; continuous signal detecting circuit detects the continuation of &ldquo;1&rdquo; in a specified number of bits in the input data (DATA) and updates the hold value in the hold circuit.

Optical transmitter circuit

The present invention provides a light emitting element driving apparatus having a driving unit for driving a light emitting element by means of a driving signal while performing automatic light power control, which enables a light output to rise at a high speed in the head portion of a burst signal to be first inputted and light outputs of a second burst signal after the first burst signal and signals thereafter to be stably supplied irrespective of holding time. To this end, the light emitting element driving apparatus comprises a reference voltage generation unit for generating a reference voltage from an input electric signal containing data information, the reference voltage being used for obtaining a light output having specified power from the light emitting element in a normal condition, a monitoring voltage generation unit for generating a monitoring voltage signal corresponding to power of an optical signal outputted from the light emitting element, a light power control unit for controlling, based on a result of comparison from the reference voltage and the monitoring voltage signal, the driving unit by a discrete control amount such that a light output from the light emitting element can have the specified power and an initial value setting unit for setting a raising component as an initial value in a control signal having the discrete control amount.

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Sapporo, Japan

Toru Matsuyama