CN204517815U - A kind of luminous power overload protecting circuit - Google Patents

Abstract

The utility model relates to the field of optical communication, and discloses an optical power overload protection circuit to solve the problem of optical power overload in the prior art by connecting resistors in series between the APD and the corresponding working voltage. The accuracy and complexity, but it is difficult to obtain the best receiving sensitivity, and even the technical problems of APD not working properly. The circuit includes: a photocurrent detector, which is used to detect the size of the received optical power and convert it into a current signal; an optical power classification circuit, which is used to determine the first attenuation value of the optical signal based on the first current value of the current signal, and based on the first current value of the current signal. An attenuation value generates a control signal for controlling the power of the optical signal; the optical signal input terminal is used to receive the optical signal; the optical power attenuator is used to control the power of the optical signal based on the control signal to be less than a preset power value; the optical signal output The terminal is used to receive the optical signal input by the optical power attenuator and output it. The technical effect of ensuring the sensitivity of signal reception is achieved.

Description

A kind of optical power overload protection circuit

technical field

The utility model relates to the field of optical communication, in particular to an optical power overload protection circuit.

Background technique

In the prior art, the optical receiving equipment frequently suffers from the technical problem that the receiving optical power overload affects the service life of the photodetector, resulting in a decrease in its sensitivity, an increase in the receiving bit error rate, affecting normal communication, and even causing permanent damage, causing major damage to users. Influence.

At present, the industry's solution to eliminate optical power overload is mainly to connect a resistor in series between the APD (Avalanche PhotoDiode, avalanche photodiode) and the corresponding working voltage. protect the circuit.

There are at least the following technical problems in the solutions of the prior art:

① While reducing the APD voltage, this solution introduces more noise because the APD cannot work in the best receiving state, which will also affect the receiving sensitivity and may cause bit errors;

②The selection of the resistor requires repeated experiments and debugging, and due to the complexity of the selection of the resistance value, it is difficult to obtain the best receiving sensitivity, and even the APD cannot work normally;

③ This solution can only be used in photodetectors containing APDs that require sufficient reverse bias voltage to work in the best receiving state. The method of reducing the reverse bias voltage is mainly used, while for EPON (Ethernet Passive Optical Network: Ethernet passive optical network) unit does not contain APD equipment, it will not be able to solve the problem of receiving optical power overload;

④ This resistor will also generate additional power loss.

Utility model content

The utility model provides an optical power overload protection circuit to solve the technical problem of low receiving sensitivity when the optical power overload problem is solved by reducing the resistance of the APD in the prior art.

The embodiment of the utility model provides an optical power overload protection circuit, including:

a photocurrent detector for receiving an optical signal and converting the optical power of the optical signal into a current signal;

an optical power grading circuit, connected to the photocurrent detector, for determining a first attenuation value of the optical signal based on the first current value of the current signal, and generating an optical signal for the optical signal based on the first attenuation value A control signal for power control;

an optical signal input terminal for receiving the optical signal;

An optical power attenuator, connected to the optical power classification circuit and the optical signal input end, is used to control the power of the optical signal based on the control signal after receiving the optical signal input from the optical signal input end Less than the preset power value;

The optical signal output end is connected to the optical power attenuator, and is used for receiving and outputting the optical signal input by the optical power attenuator.

Optionally, also include:

The attenuation value setting pin is connected to the optical power classification circuit and is used for setting the minimum attenuation value of the optical signal.

Optionally, the optical power classification circuit is specifically used for:

The first attenuation value corresponding to the first current value is determined based on the correspondence between the current value and the attenuation value.

Optionally, the optical power classification circuit is specifically used for:

determining a first current range corresponding to the first current value;

Determine the first attenuation value corresponding to the first current range.

Optionally, the optical power classification circuit is specifically used for:

determining a first power value corresponding to the first current value;

Determine the first attenuation value corresponding to the first power value.

Optionally, the optical power grading circuit is specifically configured to: generate a current control signal for controlling the optical power attenuator based on the first attenuation value; or generate a current control signal for controlling the optical power attenuator based on the first attenuation value. Voltage control signal for power attenuator control.

The beneficial effects of the utility model are as follows:

Because in the embodiment of the present invention, an optical power overload protection circuit is provided, including: a photocurrent detector, which is used to detect the received optical signal and convert the optical power of the optical signal into a current signal; an optical power classification circuit , connected to the photocurrent detector, configured to determine a first attenuation value of the optical signal based on the first current value of the current signal, and generate a signal for controlling the optical power based on the first attenuation value A control signal; an optical signal input end, used to receive the optical signal; an optical power attenuator, connected to the optical power classification circuit and the optical signal input end, for receiving the input signal from the optical signal input end After the optical signal, control the power of the optical signal to be less than a preset power value based on the control signal; the output end of the optical signal is connected to the optical power attenuator for receiving the optical signal input by the optical power attenuator and output. That is, the power of the optical signal is controlled within an appropriate range by directly adjusting the received optical power without reducing the APD reverse bias voltage, which solves the problem that the APD cannot work in the best receiving state due to the reduction of the APD voltage. The technical problem of increasing the noise, resulting in a decrease in sensitivity and an increase in bit error rate, achieves the technical effect of preventing optical power overload while ensuring the sensitivity of signal reception, and at the same time ensuring that the bit error rate will not increase;

Moreover, since there is no need to increase the resistance, it will not cause additional power loss;

Moreover, since this solution controls the power of the optical signal within an appropriate range by directly adjusting the received optical power, it does not need to add series resistors to the APD to adjust the power supply voltage for the APD to work. Therefore, for optoelectronics that do not contain APD Detectors are also suitable;

Moreover, due to the optical power grading circuit in this solution, first determine the first current range corresponding to the first current value; then determine the first attenuation value corresponding to the first current range, that is to say, for the optical power attenuation size classification configuration , reasonable attenuation can be achieved without precise adjustment and repeated testing of component values, so the response speed is fast and the use is convenient;

Moreover, the minimum attenuation value of the optical signal can be configured through the attenuation value setting pin, so it can flexibly meet the needs of the actual circuit.

Description of drawings

Fig. 1 is the structural diagram of the optical power overload protection circuit in the utility model embodiment;

Fig. 2 is a flow chart of the optical power overload protection method in the embodiment of the present invention.

Detailed ways

The utility model provides an optical power overload protection circuit to solve the technical problem of low receiving sensitivity when the optical power overload problem is solved by reducing the resistance of the APD in the prior art.

The technical solution in the embodiment of the present application is to solve the above-mentioned technical problems, and the general idea is as follows:

Provided is an optical power overload protection circuit, comprising: a photocurrent detector, used to detect and receive an optical signal and convert the optical power of the optical signal into a current signal; an optical power classification circuit, connected to the photocurrent detector A device, configured to determine a first attenuation value of the optical signal based on the first current value of the current signal, and generate a control signal for controlling the optical power based on the first attenuation value; an optical signal input terminal, for receiving the optical signal; an optical power attenuator, connected to the optical power classification circuit and the optical signal input end, for receiving the optical signal input from the optical signal input end, based on the control The signal controls the power of the optical signal to be less than a preset power value; the output end of the optical signal is connected to the optical power attenuator for receiving and outputting the optical signal input by the optical power attenuator. That is, the power of the optical signal is controlled within an appropriate range by directly adjusting the received optical power without reducing the APD reverse bias voltage, which solves the problem that the APD cannot work in the best receiving state due to the reduction of the APD voltage. The technical problem of increasing the noise, resulting in a decrease in sensitivity and an increase in bit error rate, achieves the technical effect of preventing optical power overload while ensuring the sensitivity of signal reception, and at the same time ensuring that the bit error rate will not increase;

Moreover, since there is no need to increase the resistance, it will not cause additional power loss;

Moreover, since this solution controls the power of the optical signal within an appropriate range by directly adjusting the received optical power, it does not need to add series resistors to the APD to adjust the power supply voltage for the APD to work. Therefore, for optoelectronics that do not contain APD Detectors are also suitable;

Moreover, due to the optical power grading circuit in this solution, first determine the first current range corresponding to the first current value; then determine the first attenuation value corresponding to the first current range, that is to say, for the optical power attenuation size classification configuration , reasonable attenuation can be achieved without precise adjustment and repeated testing of component values, so the response speed is fast and the use is convenient;

Moreover, the minimum attenuation value of the optical signal can be configured through the attenuation value setting pin, so it can flexibly meet the needs of the actual circuit.

In order to better understand the above-mentioned technical solution, the technical solution of the utility model will be described in detail below through the accompanying drawings and specific examples. To illustrate, rather than to limit the technical solution of the utility model, the embodiments of the utility model and the technical features in the embodiments can be combined with each other under the condition of no conflict.

In the first aspect, the embodiment of the present invention provides an optical power overload protection circuit, please refer to Figure 1, including:

The photocurrent detector 2 is used to detect the received optical signal and convert the optical power of the optical signal into a current signal;

An optical power classification circuit 4, connected to the photocurrent detector 2, configured to determine a first attenuation value of the optical signal based on the first current value of the electrical signal, and generate a control signal for controlling the optical power based on the first attenuation value;

The optical signal input terminal 1 is used to receive the optical signal;

The optical power attenuator 3 is connected to the optical power classification circuit 4 and the optical signal input terminal 1, and is used to control the power of the optical signal based on the control signal to be less than a preset power value after receiving the optical signal input from the optical signal input terminal 1;

The optical signal output port 8 is connected to the optical power attenuator 3 and is used for receiving and outputting the optical signal input by the optical power attenuator 3 .

For example, the optical power overload protection circuit is applied to GPON ONU (Gigabit Passive Optical Network Optical Network Unit: Gigabit Passive Optical Network Optical Network Unit), GPON (Gigabit Passive Optical Network: Gigabit Passive Optical Network) optical module , EPON ONU (Ethernet Passive Optical Network Optical Network Unit: Ethernet Passive Optical Network Optical Network Unit) or EPON optical module, etc., wherein GPON ONU, GPON optical module contains APD, EPON ONU or EPON optical module does not contain APD.

The above-mentioned components will be introduced respectively below.

Wherein, after the optical signal enters the optical power overload protection circuit, it is divided into two lines, and the optical signal of the first line enters the photocurrent detector 2, and is converted into a current signal by the photocurrent detector 2.

The optical power classification circuit 4 mainly determines whether the optical signal is overloaded through the first current value of the current signal (because there is a certain relationship between the optical power and the current value detected by the photocurrent detector), and then based on whether the power of the optical signal is The first attenuation value of the optical signal is determined by the overload and the degree of the overload. The following three determination methods are listed for introduction. Of course, in the specific implementation process, it is not limited to the following three situations.

The first type, the optical power grading circuit 4, is specifically configured to: determine the first attenuation value corresponding to the first current value based on the correspondence between the current value and the attenuation value.

For example, in the initial stage, for each current value, it is possible to determine the attenuation value corresponding to the power value that can keep the optical signal less than the preset power value, and store the corresponding relationship between the current value and the attenuation value, and then pass This correspondence can obtain the first attenuation value corresponding to the first current value, thereby realizing the control of the power of the optical signal. Since each current value has its corresponding attenuation value, it has the technical effect of more precise control .

The second type is the optical power classification circuit 4, which is specifically used to: determine the first current range corresponding to the first current value; and determine the first attenuation value corresponding to the first current range.

For example, the optical power grading circuit 4 can first divide the received optical power in daily use into segments, and for the detection current value corresponding to the maximum optical power in each range, for example: between the power of the optical signal and the detection current value The following correspondences can exist:

Detection current value = power of optical signal * responsivity…………………[1] Unit conversion relationship:

dBm＝10*log ₁₀ (optical power/1mW)……………………[2]

Wherein, the response efficiency varies according to the material of the photocurrent detector 2 , and is generally equal to 0.85A/w or 0.8A/w.

Usually, when the optical signal is in a certain range, it can correspond to the same attenuation value, for example, the corresponding relationship shown in Table 1:

Table 1

Optical signal power (dBm) <-8 -8～-4 -4～0 0～3 Attenuation value (dB) 0 5 10 15

Then the above Table 1 can be converted into the corresponding relationship between the current value and the attenuation value, for example, as shown in Table 2, where the responsivity is 0.85A/w:

Table 2

Current value (uA) <135 135～338 338～850 850～1696 Attenuation value (dB) 0 5 10 15

Furthermore, after the optical power grading circuit 4 acquires the first current value of the electrical signal, it can determine the first attenuation value of the optical signal through the above Table 2.

The third type is the optical power classification circuit 4, which is specifically used to: determine the first power value corresponding to the first current value; determine the first attenuation value corresponding to the first power value.

For example, the first power value can be calculated by the above formula [1]. After the first power value is calculated, the first attenuation value can be determined in various ways. Two of them are listed below for introduction , of course, in the specific implementation process, it is not limited to the following two situations.

① Determine the first attenuation value based on the corresponding relationship between the power value and the attenuation value.

For example, in the initial stage, for the power value of each optical signal, it is possible to determine the attenuation value corresponding to the power value of the optical signal that can keep the power value of the optical signal less than the preset power value, and store the correspondence between the power value of the optical signal and the attenuation value relationship, and then directly obtain the first attenuation value corresponding to the first power value through the corresponding relationship.

② Determine the first power value range corresponding to the first power value, and determine the first attenuation value corresponding to the first power value range.

Taking the corresponding relationship between the power value range and the attenuation value shown in Table 1 as an example, assuming that the first power value is 2dBm, the first power value range can be determined to be 0-3dBm, thereby determining that the first attenuation value is 15dB .

After the optical signal enters the optical power overload protection circuit, the optical signal passing through the second line directly enters the optical signal input terminal 1, and then passes through the optical power attenuator 3;

After the optical power attenuator 3 receives the optical signal, it can control the power of the optical signal through the control signal sent by the optical power classification circuit 4 . The preset power value is, for example, -8dBm (of course it can also be other values, such as: 0dBm, -4dBm, etc.), wherein if the power of the optical signal is not greater than -8dBm, the first attenuation value corresponding to the control signal is 0 , that is, the power of the optical signal will not be changed; if the power of the optical signal is greater than -8dBm, the first attenuation value corresponding to the control signal will be different according to the power of the optical signal. Through the control of the optical power attenuator 3 , it can ensure that the power of the optical signal is less than the preset power value, thereby realizing the overload protection of the power of the optical signal. The optical power attenuator 3 is, for example, an electronically controlled optical power attenuator 3 .

In the specific implementation process, when the optical power classification circuit 4 generates the control signal, various forms of control signals can be generated, two of which are listed below for introduction, of course, in the specific implementation process, it is not limited to the following two cases.

The first type, the optical power classification circuit 4, is specifically used for: generating a current control signal for controlling the optical power attenuator 3 based on the attenuation value.

The second type, the optical power classification circuit 4, is specifically used for: generating a voltage control signal for controlling the optical power attenuator 3 based on the attenuation value.

As a further preferred embodiment, please continue to refer to Figure 1, the circuit also includes:

The attenuation value setting pin 5 is connected to the optical power classification circuit 4, and is used to set the minimum attenuation value of the optical signal, wherein the minimum attenuation value is, for example: 5dB, 3dB, etc., and different minimum attenuation values can be set according to actual needs. In addition , you can also set the step value of the attenuation value, for example: 5dB, 10dB and so on. The optical power grading circuit 4 is internally configured with an attenuation step for attenuation classification, but the internal components can be adjusted to flexibly realize a step of 3dB or 5dB.

As a further preferred embodiment, please continue to refer to Figure 1, the circuit also includes:

Grounding pin 7, one end of the grounding pin is connected to the optical power classification circuit 4, and the other end is grounded;

VCC (power input pin: Voltage Current Condenser) 5 is connected to the optical power classification circuit 4 for supplying power to the circuit.

In the second aspect, based on the same concept of the utility model, the embodiment of the utility model provides an optical power overload protection method, please refer to Figure 2, including:

Step S201: receiving the optical signal by the first line and converting the optical power into a current signal;

Step S202: Determine the first attenuation value of the optical power according to the first current value of the current signal;

Step S203: Generate a control signal for controlling the power of the optical signal by using the first attenuation value;

Step S204: controlling the power of the optical signal of the second line to be less than a preset power value through the control signal;

Step S205: After adjusting the power of the optical signal, output the optical signal.

Optionally, the first attenuation value of the optical signal is determined by the first current value of the electrical signal, specifically:

Based on the correspondence between the current value and the attenuation value, a first attenuation value corresponding to the first current value is determined.

Optionally, determining the first attenuation value of the optical signal through the first current value of the electrical signal specifically includes:

determining a first current range corresponding to the first current value;

Determine the first attenuation value corresponding to the first current range.

Optionally, determining the first attenuation value of the optical signal through the first current value of the electrical signal specifically includes:

determining a first power value corresponding to the first current value;

A first attenuation value corresponding to the first power value is determined.

One or more embodiments of the utility model have at least the following beneficial effects:

In the embodiment of the present invention, an optical power overload protection circuit is provided, including: a photocurrent detector, used to detect the size of the received optical power and convert it into a current signal; an optical power classification circuit, connected to the optical A current detector, configured to determine a first attenuation value of the optical signal based on the first current value of the current signal, and generate a control signal for controlling the optical power based on the first attenuation value; the optical signal input end, used to receive the optical signal; an optical power attenuator, connected to the optical power classification circuit and the optical signal input end, for receiving the optical signal input from the optical signal input end, based on the The control signal controls the power of the optical signal to be less than a preset power value; the output end of the optical signal is connected to the optical power attenuator for receiving and outputting the optical signal input by the optical power attenuator. That is, the power of the optical signal is controlled within an appropriate range by directly adjusting the received optical power without reducing the APD reverse bias voltage, which solves the problem that the APD cannot work in the best receiving state due to the reduction of the APD voltage. The technical problem of increasing the noise, resulting in a decrease in sensitivity and an increase in bit error rate, achieves the technical effect of preventing optical power overload while ensuring the sensitivity of signal reception, and at the same time ensuring that the bit error rate will not increase;

Moreover, since there is no need to increase the resistance, it will not cause additional power loss;

Moreover, since this solution controls the power of the optical signal within an appropriate range by directly adjusting the received optical power, it does not need to add series resistors to the APD to adjust the power supply voltage for the APD to work. Therefore, for optoelectronics that do not contain APD Detectors are also suitable;

Moreover, due to the optical power grading circuit in this solution, first determine the first current range corresponding to the first current value; then determine the first attenuation value corresponding to the first current range, that is to say, for the optical power attenuation size classification configuration , reasonable attenuation can be achieved without precise adjustment and repeated testing of component values, so the response speed is fast and the use is convenient;

Moreover, the minimum attenuation value of the optical signal can be configured through the attenuation value setting pin, so it can flexibly meet the needs of the actual circuit.

While preferred embodiments of the present invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, the appended claims are intended to be interpreted to cover the preferred embodiment and all changes and modifications which fall within the scope of the present invention.

Apparently, those skilled in the art can make various changes and modifications to the present utility model without departing from the spirit and scope of the present invention. In this way, if these modifications and variations of the utility model fall within the scope of the claims of the utility model and equivalent technologies thereof, the utility model is also intended to include these modifications and variations.

Claims (2)

1. a luminous power overload protecting circuit, is characterized in that, comprising:

Photocurrent detection device, is converted to current signal for receiving optical signals by the size of the luminous power of described light signal;

Luminous power stage circuit, is connected to described photocurrent detection device, for determining the first pad value of described light signal based on the first current value of described current signal, and produces based on described first pad value the control signal controlled described luminous power;

Optical signal input, for receiving described light signal;

Optical power attenuation device, is connected to described luminous power stage circuit and described optical signal input, and for after the light signal receiving the input of described optical signal input, the power controlling described light signal based on described control signal is less than predetermined power value;

Light signal output end, is connected to described optical power attenuation device, for receiving the light signal of described optical power attenuation device input and exporting.

2. circuit as claimed in claim 1, is characterized in that, also comprise:

Pad value arranges pin, is connected to described luminous power stage circuit, for arranging the minimal attenuation value of described light signal.