Abstract: An optical receiving device includes: a conversion device that converts an input burst optical signal into a positive phase electrical signal and a negative phase electrical signal; an amplification device that amplifies the positive phase electrical signal and the negative phase electrical signal; a first output terminal that outputs the positive phase electrical signal; a second output terminal that outputs the negative electrical signal; a first transmission line that couples the amplification device with the first output terminal and transmits the positive phase electrical signal; a second transmission line that couples the amplification device with the second output terminal and transmits the negative phase electrical signal; and a control device that reduces a potential difference between the first transmission line and the second transmission line in a no-signal period that is provided between burst optical signals.

Abstract: A detecting apparatus includes a threshold detection circuit that detects by a switchable time constant, a threshold of a level of an input optical burst signal; an input detection circuit that detects input of the optical burst signal; a level detection circuit that detects a level of the optical burst signal; a switching circuit that switches the time constant when a period that corresponds to the level detected by the level detection circuit has elapsed after the input is detected by the input detection circuit; and an output circuit that outputs the threshold detected by the threshold detection circuit.

Abstract: An optical receiving device includes: a conversion device that converts an input burst optical signal into a positive phase electrical signal and a negative phase electrical signal; an amplification device that amplifies the positive phase electrical signal and the negative phase electrical signal; a first output terminal that outputs the positive phase electrical signal; a second output terminal that outputs the negative electrical signal; a first transmission line that couples the amplification device with the first output terminal and transmits the positive phase electrical signal; a second transmission line that couples the amplification device with the second output terminal and transmits the negative phase electrical signal; and a control device that reduces a potential difference between the first transmission line and the second transmission line in a no-signal period that is provided between burst optical signals.

Abstract: A detecting apparatus includes a threshold detection circuit that detects by a switchable time constant, a threshold of a level of an input optical burst signal; an input detection circuit that detects input of the optical burst signal; a level detection circuit that detects a level of the optical burst signal; a switching circuit that switches the time constant when a period that corresponds to the level detected by the level detection circuit has elapsed after the input is detected by the input detection circuit; and an output circuit that outputs the threshold detected by the threshold detection circuit.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A single-fiber bidirectional optical transmitter/receiver includes a single-fiber bidirectional optical transmission/reception device. A circuit board has a signal processing circuit and a drive circuit configured to drive the single-fiber bidirectional optical transmission/reception device. A main housing accommodates the single-fiber bidirectional optical transmission/reception device and the circuit board. A ground part of a reception side of the single-fiber bidirectional optical transmission/reception device is electrically connected to a ground part of a transmission side of the single-fiber bidirectional optical transmission/reception device through a ground wiring pattern formed on a flexible printed board.

Abstract: A single-fiber bidirectional optical transmitter/receiver includes a single-fiber bidirectional optical transmission/reception device. A circuit board has a signal processing circuit and a drive circuit configured to drive the single-fiber bidirectional optical transmission/reception device. A main housing accommodates the single-fiber bidirectional optical transmission/reception device and the circuit board. A ground part of a reception side of the single-fiber bidirectional optical transmission/reception device is electrically connected to a ground part of a transmission side of the single-fiber bidirectional optical transmission/reception device through a ground wiring pattern formed on a flexible printed board.

Abstract: 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.

Abstract: 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.

Abstract: A optical transmitter includes a light device provided a driving current and for emitting light on the bases of the driving current; a light measure for measuring an output light level of the light device; a controller for controlling the driving current to the light device and for changing the measured output light power level into a set output light power level of the light device; a current measure for measuring a level of the driving current to the light device; an abnormality detector for detecting an aged deterioration of the light device on the bases of the current level of the driving current by the current measure and the measured output light power level by the light measure; and an adjuster for reducing the set output light power level in the controller when the abnormality detector detects the aged deterioration of the light device.

Abstract: A burst signal detection circuit for detecting the arrival of a burst-like signal, which can accurately detect the burst signal against the DC level variations even in the case where the arriving burst signal is a weak signal, is disclosed. A DC variation removing circuit detects the bottom level of an input signal and removes the DC level variation of the input signal based on the bottom level. An amplitude identifying circuit detects the presence or absence of a burst signal based on the output signal of the DC variation removing circuit. The amplitude identifying circuit includes an amplitude detection circuit for detecting the maximum amplitude of the output signal of the DC variation removing circuit, a threshold level control circuit for controlling the threshold level and a comparator for comparing the output level of the amplitude detection circuit with the threshold level and outputting a detection signal indicating the presence or absence of a burst signal.