JP2806720B2 - Optical transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for optical communication. The present invention is suitable for use in an optical transmission device that processes a burst signal. In particular, the present invention relates to a control technique when there is no signal for an optical output alarm.

[0002]

2. Description of the Related Art An optical transmission device used for optical communication is provided with a circuit for detecting an abnormal output of an optical signal. The configuration of the conventional apparatus will be described with reference to FIG. FIG. 3 is a block diagram of a conventional apparatus. In FIG. 3, an electric signal 11 of a burst signal output from a transmission signal generation unit 1 is received by a laser diode driving unit 2, and the laser diode 3 is driven by a driving current 12 to output the output light 1.
3 is output. The output light is monitored by the light output monitoring light receiving element 4, and the alarm output unit 5 sends out an alarm output 19 when detecting a disconnection state of the optical signal. This alarm output unit 5
This is an alarm circuit that continuously outputs an alarm output even if the output from the light output monitoring light receiving element 4 is temporarily stopped.

[0003]

However, in optical burst signal transmission, the output light stops when there is no burst signal, so that there is a problem that an alarm output is sent out each time.

The present invention has been made in view of such a background, and an object of the present invention is to provide an optical transmission device capable of discriminating interruption of a burst signal and failure of a device and outputting an alarm.

[0005]

According to the present invention, there is provided a transmission signal generating section for generating a burst signal as an electric signal, a laser diode driving section for generating a driving current of a laser diode by an output of the transmission signal generating section, An optical transmission device includes a laser diode that is driven by a drive current to generate an optical signal, and a light output monitoring light receiving element that monitors output light of the laser diode.

Here, a feature of the present invention is that a burst signal is generated in synchronization with the transmission signal of the transmission signal generator.
A signal detection clock generation unit that generates a clock signal for each raw; and a signal state detection unit that receives the clock signal and the output of the light receiving element. The signal state detection unit receives the clock signal. Means for sending out an output when there is no output from the light receiving element when the light is received.

It is desirable to have an alarm circuit for continuously outputting an alarm output when the output of the signal state detector is sent.

[0008]

Each time a burst signal as a transmission signal is generated, the signal detection clock generator generates one clock pulse. If the laser diode does not emit light when the clock pulse is generated, it is an abnormal condition. Conversely, if the laser diode does not emit light when no clock pulse is generated, it is not an abnormal state.

The light output monitoring light receiving element detects the blinking of the laser diode, and the signal state detection section receives the outputs of the light output monitoring light receiving element and the signal detection clock generation section as inputs, and generates a clock pulse. If the light emission of the laser diode is not detected when it is generated, it is determined that an abnormal state is present, and an abnormal output is sent to the alarm output unit. The alarm output section continuously outputs an alarm output even when an abnormal output from the signal state detection section is temporarily transmitted.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

According to the present invention, a transmission signal generator 1 for generating a burst signal as an electric signal 11 and a laser diode driver for generating a laser diode driving current 12 based on the electric signal 11 output from the transmission signal generator 1 2 and
A laser diode 3 driven by the drive current 12 to generate an optical signal, and an output light 1 of the laser diode 3
3 is an optical transmission device provided with a light output monitoring light receiving element 4 for monitoring the light transmission element 3.

The feature of the present invention is that the burst signal is synchronized with the transmission signal 17 of the transmission signal generator 1.
A signal detection clock generator 7 for generating a clock signal 18 each time it is generated, and a signal state detector 6 which receives the clock signal 18 and the light-receiving element output 16 of the light-output monitoring light-receiving element 4 as inputs. The state detecting section 6 is provided with a means for transmitting an output when the light receiving element output 16 of the light output monitoring light receiving element 4 does not exist when the clock signal 18 is input.

The alarm output unit 5 is provided as an alarm circuit for continuously outputting an alarm output 19 when the abnormal output 15 of the signal state detection unit 6 is transmitted.

Next, the operation of the apparatus according to the embodiment of the present invention will be described. The transmission signal generator 1 converts the input communication information into an electric signal 11 of a burst signal. This burst signal 1
1 receives the driving current 12
Drives the laser diode 3. Thereby, the electrical signal 11 of the burst signal is converted into the output light 13. The light output monitoring light receiving element 4 monitors the output light 13.

The transmission signal generator 1 sends a signal 17 to the signal detection clock generator 7 as generation information of a burst signal.
And the signal detection clock generator 7 generates one clock signal 18 each time a burst signal is generated.

Next, the operation of the signal state detector 6 will be described with reference to FIG. FIG. 2 is a time chart showing the operation of the signal state detector 6. The light receiving element output 16 corresponds to the blinking of the laser diode 3 and the light output monitoring light receiving element 4.
Output from The clock signal 18 is generated by the signal detection clock generator 7 each time the transmission signal generator 1 generates the transmission signal 17. The signal state detection unit 6 outputs the light receiving element output 1
6 and the clock signal 18 are input, and as shown in FIG. 2A, if the light receiving element output 16 does not exist when the clock signal 18 does not exist, the abnormal output 15 is not transmitted because it is not in an abnormal state. Here, abnormal output 1
When 5 is the L value, it is regarded as abnormal. As shown in FIG. 2B, when the clock signal 18 is present, the light receiving element output 1
If 6 does not exist, it is an abnormal state and abnormal output 1
5 is sent out. The alarm output unit 5 is an alarm circuit that operates to continuously output the alarm output 19 even when the abnormal output 15 is temporarily transmitted.

In the embodiment of the present invention, the abnormal output 15 has been described as the L value. This is because a failure of the signal state detection unit 6 can be detected by always sending the signal of the H value from the signal state detection unit 6 in a normal state.

The abnormal output 15 may be set to an H value.

[0019]

As described above, according to the present invention, it is possible to discriminate between the interruption of the burst signal and the failure of the device and output an alarm. Thereby, erroneous transmission of the alarm output can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a time chart illustrating an operation of a signal state detection unit.

FIG. 3 is a block diagram of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission signal generation part 2 Laser diode drive part 3 Laser diode 4 Optical output monitoring light receiving element 5 Alarm output part 6 Signal state detection part 7 Signal detection clock generation part 11 Electric signal 12 Drive current 13 Output light 15 Abnormal output 16 Light reception Element output 17 Transmission signal 18 Clock signal

Claims (2)

(57) [Claims] A transmission signal generator for generating a burst signal as an electric signal; a laser diode driver for generating a laser diode drive current based on an output of the transmission signal generator; and an optical signal driven by the drive current. An optical transmission device comprising: a generated laser diode; and a light output monitoring light receiving element for monitoring output light of the laser diode, wherein a burst signal is synchronized with a transmission signal of the transmission signal generation unit.
A signal detection clock generation unit for generating a clock signal each time the signal is generated; and a signal state detection unit that receives the clock signal and the output of the light receiving element as inputs. The signal state detection unit receives the clock signal. An optical transmission device comprising means for transmitting an output when there is no output from the light receiving element when the light is received. 2. The optical transmission device according to claim 1, further comprising an alarm circuit for continuously outputting an alarm output when the output of the signal state detection unit is transmitted.