CN106992811A - The method of testing and system of optical modulation amplitude value in receiving sensitivity measurement - Google Patents

Abstract

A test method and system for optical modulation amplitude value in receiving sensitivity measurement; the test method includes: measuring the receiving sensitivity of the optical module to be tested, recording the receiving sensitivity as the first power; adjusting the input to the optical module to be tested After the input optical power at the receiving end of the module falls within a predetermined power range, record the input optical power as the second power, and measure the second optical modulation amplitude; divide the second optical modulation amplitude by the second power, multiply by The first power obtains a first light modulation amplitude in receiving sensitivity measurement. The invention provides an improved testing scheme of light modulation amplitude value in receiving sensitivity measurement.

Description

Method and system for testing optical modulation amplitude value in receiving sensitivity measurement

technical field

The invention relates to the field of optical communication, in particular to a method and system for testing optical modulation amplitude values in receiving sensitivity measurement.

Background technique

When evaluating the signal transmission capability of an Ethernet optical interface, it is often necessary to consider the test of receiving sensitivity parameters, especially the evaluation based on the optical modulation amplitude. For non-return-to-zero signals, the optical modulation amplitude is defined as the power difference between the high-level signal and the low-level signal. However, when measuring the input optical signal with an oscilloscope, the test accuracy is often affected by the input optical power. The smaller the input optical power, the greater the test error. When measuring the receiving sensitivity, the optical modulation amplitude cannot be directly obtained. The conventional method is through Measure its extinction ratio, and then use the formula to calculate the corresponding OMA (Optical Modulation Amplitude, optical modulation amplitude), as follows:

Among them, SEN _OMA is the linear value of optical modulation amplitude in receiving sensitivity measurement, SEN is the linear value of receiving sensitivity, and ER is the decibel value of extinction ratio. It can be seen that the test idea is to first test the receiving sensitivity, and then use the extinction ratio parameter to calculate The optical modulation amplitude when measuring the receiving sensitivity is shown.

Although the above method solves the test of the receiving sensitivity optical modulation amplitude value of the non-return-to-zero signal, the calculation is slightly complicated and involves the measurement of the intermediate parameter extinction ratio, and if it involves high-order modulation, such as four-level pulse amplitude modulation, the calculation formula Needs to be redesigned. Therefore, it is necessary to study and improve the existing testing methods.

Contents of the invention

The invention provides an improved testing scheme of light modulation amplitude value in receiving sensitivity measurement.

In order to solve the above problems, the present invention adopts the following technical solutions.

A test method for optical modulation amplitude value in receiving sensitivity measurement, comprising:

Measuring the receiving sensitivity of the optical module to be tested, and recording the receiving sensitivity as the first power;

After adjusting the input optical power input to the receiving end of the optical module to be tested to within a predetermined power range, record the input optical power as the second power, and measure the second optical modulation amplitude;

The second light modulation amplitude is divided by the second power, and multiplied by the first power to obtain the first light modulation amplitude in receiving sensitivity measurement.

Optionally, the measuring the second light modulation amplitude includes:

Using an optical oscilloscope to measure the optical modulation amplitude of the receiving end of the optical module to be tested as the second optical modulation amplitude.

Optionally, the predetermined power interval is the power measurement range of the optical oscilloscope;

Alternatively, the predetermined power interval is within the power measurement range of the optical oscilloscope.

Optionally, the measuring the receiving sensitivity of the optical module to be tested includes:

Adjust the input optical power input to the receiving end of the optical module under test in a descending manner, until the bit error rate of the optical module under test reaches a first predetermined threshold, use an optical power meter to measure the optical power under test The input optical power of the receiving end of the module is used to obtain the receiving sensitivity of the optical module to be tested.

Optionally, the adjusting the input optical power input to the receiving end of the optical module under test includes:

Adjusting the adjustable attenuator arranged between the sending end of the reference transmitter and the receiving end of the optical module under test to increase or decrease the input optical power input to the receiving end of the optical module under test.

Optionally, the dividing the second optical modulation amplitude by the second power and multiplying by the first power to obtain the first optical modulation amplitude in the receiving sensitivity measurement includes:

converting the first power, the second power, and the second optical modulation amplitude into corresponding decibel milliwatts;

After the conversion, subtract the power difference from the second light modulation amplitude to obtain the first light modulation amplitude in receiving sensitivity measurement; the power difference is the second power minus the first power.

A test system for the optical modulation amplitude value in receiving sensitivity measurement, comprising: a reference transmitter, an adjustable attenuator arranged between the sending end of the reference transmitter and the receiving end of the optical module to be tested, an optical power meter, an optical oscilloscope, a control equipment;

The control device is used to adjust the adjustable attenuator to measure the receiving sensitivity of the optical module to be tested, and record the receiving sensitivity measured by the optical power meter as the first power; for adjusting the adjustable attenuator After the input optical power input to the receiving end of the optical module to be tested falls within a predetermined power range, the input optical power measured by the optical power meter is recorded as the second power, and the second optical power is obtained from the optical oscilloscope. Modulation amplitude: dividing the second optical modulation amplitude by the second power and multiplying by the first power to obtain the first optical modulation amplitude in receiving sensitivity measurement.

Optionally, the predetermined power interval is the power measurement range of the optical oscilloscope;

Alternatively, the predetermined power interval is within the power measurement range of the optical oscilloscope.

Optionally, the test system also includes:

A bit error analyzer for measuring the bit error rate of the optical module to be tested;

The control device used to adjust the adjustable attenuator to measure the receiving sensitivity of the optical module under test includes:

The control device adjusts the adjustable attenuator so that the input optical power input to the receiving end of the optical module under test changes from large to small until the bit error rate measured by the bit error analyzer reaches When the first predetermined threshold is reached, the input optical power of the receiving end of the optical module under test measured by the optical power meter is recorded to obtain the receiving sensitivity of the optical module under test.

Optionally, the control device divides the second optical modulation amplitude by the second power, and multiplies the second optical modulation amplitude by the first power to obtain the first optical modulation amplitude in the receiving sensitivity measurement including:

The control device converts the first power, the second power, and the second optical modulation amplitude into corresponding decibel milliwatts; after conversion, the second optical modulation amplitude is subtracted from the power difference to obtain the first optical modulation amplitude in the receiving sensitivity measurement. an optical modulation amplitude; the power difference is the second power minus the first power.

Using the optical modulation amplitude test scheme provided by the embodiment of the present invention, compared with the prior art, it can realize the test of the optical modulation amplitude value under lower optical power, the test steps are simple, no complicated calculation is involved, and it is suitable for non-return-to-zero signals It can also be applied to the test of the four-level pulse amplitude modulation signal, and the test accuracy can be guaranteed at the same time.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Description of drawings

The accompanying drawings are used to provide a further understanding of the technical solution of the present invention, and constitute a part of the description, and are used together with the embodiments of the application to explain the technical solution of the present invention, and do not constitute a limitation to the technical solution of the present invention.

Fig. 1 is the schematic flow chart of the test method of optical modulation amplitude value in the receiving sensitivity measurement of embodiment 1;

Fig. 2 is the hardware system block diagram in the example of embodiment one;

Fig. 3 is the schematic flow chart of the example of embodiment one;

FIG. 4 is a block diagram of a test system for the optical modulation amplitude value in the receiving sensitivity measurement of the second embodiment.

detailed description

The technical solution of the present invention will be described in more detail below with reference to the drawings and embodiments.

It should be noted that, if there is no conflict, the embodiments of the present invention and various features in the embodiments can be combined with each other, and all are within the protection scope of the present invention. In addition, although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in an order different from that shown or described herein.

Embodiment 1. A test method for optical modulation amplitude value in receiving sensitivity measurement, as shown in FIG. 1 , including steps S110-S130:

S110. Measure the receiving sensitivity of the optical module to be tested, and record the receiving sensitivity as the first power;

S120. After adjusting the input optical power input to the receiving end of the optical module to be tested to within a predetermined power range, record the input optical power as a second power, and measure a second optical modulation amplitude;

S130. Divide the second optical modulation amplitude by the second power, and multiply by the first power to obtain the first optical modulation amplitude in receiving sensitivity measurement.

In this embodiment, the sequence of S120 and S110 is not limited. Since the receiving sensitivity needs to be measured in S110, and the optical modulation amplitude needs to be measured in S120, the input optical power in S110 must be smaller than the input optical power in S120; S110 can be performed first during the test (if the input optical power is not suitable, adjust until it is suitable), and then increase the input optical power to perform S120, or first perform S120 (if the input optical power is not suitable, adjust until it is suitable), and then decrease the input optical power to perform S110.

In this embodiment, for S110, the appropriate input optical power is the input optical power that is small enough to measure the receiving sensitivity; for S120, the appropriate input optical power is the input optical power that is small enough to measure the optical modulation amplitude.

Optionally, the measuring the second light modulation amplitude includes:

Using an optical oscilloscope to measure the optical modulation amplitude of the receiving end of the optical module to be tested as the second optical modulation amplitude.

In other optional solutions, other methods may also be used to measure the light modulation amplitude.

In this optional solution, the predetermined power interval is the power measurement range of the optical oscilloscope;

Alternatively, the predetermined power interval is within the power measurement range of the optical oscilloscope.

For example, the power measurement range of the optical oscilloscope is Px～Py, including Px and Py, wherein Py is greater than Px; the predetermined power interval can be directly set as the power measurement range, that is: Px～Py, including Px and Py; The predetermined power interval may also fall within the power measurement range, that is, the upper limit value of the predetermined power interval is less than or equal to Py, and the lower limit value is greater than or equal to Px.

In other optional solutions, the predetermined power range may also be set according to actual conditions.

Optionally, the measuring the receiving sensitivity of the optical module to be tested includes:

Adjust the input optical power input to the receiving end of the optical module under test in a descending manner, until the bit error rate of the optical module under test reaches a first predetermined threshold, use an optical power meter to measure the optical power under test The input optical power of the receiving end of the module is used to obtain the receiving sensitivity of the optical module to be tested.

In other optional solutions, other methods may also be used to measure the receiving sensitivity.

Optionally, the adjusting the input optical power input to the receiving end of the optical module under test includes:

Adjusting the adjustable attenuator arranged between the sending end of the reference transmitter and the receiving end of the optical module under test to increase or decrease the input optical power input to the receiving end of the optical module under test.

In other optional solutions, other ways may also be used to adjust the input optical power input to the receiving end of the optical module to be tested.

Optionally, the dividing the second optical modulation amplitude by the second power and multiplying by the first power to obtain the first optical modulation amplitude in the receiving sensitivity measurement includes:

converting the first power, the second power, and the second optical modulation amplitude into corresponding decibel milliwatts;

After the conversion, subtract the power difference from the second light modulation amplitude to obtain the first light modulation amplitude in receiving sensitivity measurement; the power difference is the second power minus the first power.

In this alternative solution, the multiplication and division operations are converted into addition and subtraction operations, which further reduces the computational complexity.

In an example of this embodiment, the hardware system test block diagram corresponding to the test method is shown in Figure 2, including: a bit error analyzer, a reference transmitter, the receiving part Rx of the optical module to be tested, an adjustable attenuator, and an optical Oscilloscope and optical power meter. The output signal of the bit error analyzer is sent to the reference transmitter, and then the output signal of the reference transmitter is input to the receiving part of the optical module to be tested after passing through the adjustable attenuator, and finally enters the receiving part of the bit error analyzer. An optical power meter and an optical oscilloscope are configured at the output end of the optical adjustable attenuator for monitoring.

In this example, the flow of the test method described with reference to FIG. 3 is as follows, including steps 101-103:

Step 101: measure the receiving sensitivity _PL ;

Step 101 may include:

Adjust the adjustable attenuator so that the input optical power input to the receiving end of the optical module to be tested gradually decreases from high until the bit error rate detected by the bit error meter gradually increases and reaches the specified value, which is measured by the optical power meter. When the input optical power of the optical module to be tested is the pressurized receiving sensitivity _PL of the optical module to be tested; _PL is the first power;

For the measurement method of receiving sensitivity, reference may be made to related technologies.

Step 102: Increase the input optical power to the appropriate range of the optical oscilloscope specification, and measure the input optical power P _H and the corresponding optical modulation amplitude OMA _H ;

Step 102 may include:

Adjust the adjustable attenuator to make the input optical power of the optical oscilloscope suitable, record the input optical power P _H , P _H is the second power; test the second optical modulation amplitude OMA _H with the optical oscilloscope, if there is any error in the power measurement of the optical oscilloscope It can be eliminated by comparing and calibrating the optical power meter;

Optical oscilloscopes often have strict requirements on the input optical power during testing. Only when the input optical power is within the measurement range, the optical oscilloscope can accurately measure the optical modulation amplitude. Therefore, it is not possible to measure the receiving sensitivity when the input optical power is low. Simultaneously measure the optical modulation amplitude with an optical oscilloscope.

Step 103: Calculate the optical modulation amplitude in the receiver sensitivity measurement:

OMA _L =OMA _H -(P _H -P _L ).

The parameter units in the above steps are decibel milliwatts dBm.

The test method in this embodiment is similarly applicable to testing the optical modulation amplitude of the pressurized receiving sensitivity. The bit error analyzer needs to have a signal pressurizing function, and the optical oscilloscope can monitor the pressurized signal quality before testing the pressurized receiving sensitivity.

The basic principle of the optical modulation amplitude testing method in the receiver sensitivity measurement described in this embodiment will be described below by taking a non-return-to-zero code signal as an example.

When the receiving sensitivity is measured, the powers of the second signal and the first signal are set as P1 and P0 respectively, then the linear value of the average power _PL is 0.5×(P1+P0).

Set the extinction ratio as ER, there is ER=P1/P0. Note that adjusting the adjustable attenuator to change the signal optical power does not affect the extinction ratio. Then P _L =0.5×(P1+P1/ER). Then there is P1=k0× _PL , where k0 is a constant.

After increasing the input optical power, set the power of the second signal and the first signal to be P11 and P00 respectively when the input optical power is the second power (that is, the input optical power of the optical oscilloscope is within the predetermined power range), then the average power P The linear value of _H is 0.5×(P11+P00), and similarly, P11=k0×P _H .

Calculate the optical modulation amplitudes corresponding to the two powers respectively:

OMA _L =P1-P0=P1-P1/ER=k0× _PL ×(1-1/ER)=k× _PL ;

OMA _H =P11-P00=P11-P11/ER=k0× _PH ×(1-1/ER)=k× _PH ;

From the above two formulas, it is easy to get that OMA _L =OMA _H /P _H ×P _L .

If the above parameters are converted into decibel milliwatts as a unit, then there is OMA _L =OMA _H -(P _H -P _L ).

The derivation of the above test principle is based on the non-return-to-zero code signal, and the same applies to the test of the four-level pulse amplitude modulation signal, as follows:

When measuring the receiving sensitivity: P _L =0.25×(P0+P1+P2+P3).

P0, P1, P2, and P3 are respectively the first signal level, the second signal level, the third signal level, and the fourth signal level when measuring the receiving sensitivity.

When the input optical power is appropriate: P _H =0.25×(P00+P11+P22+P33).

P00, P11, P22, and P33 are respectively the first signal level, the second signal level, the third signal level, and the fourth signal level when the input optical power is appropriate.

It is assumed that the minimum value of OMA of the four-level pulse amplitude modulation signal is the difference between the third signal level P22 and the second signal level P11, that is, OMA _H =P22-P11.

It is not difficult to draw: OMA _H =P22-P11=k0×(P22+P11)=k× _PH . Similarly, OMA _L =k×P _L .

Therefore OMA _L =OMA _H /P _H ×P _L . Converted to decibel milliwatts, that is, OMA _L =OMA _H -(P _H -P _L ).

Embodiment 2. A test system for optical modulation amplitude value in receiving sensitivity measurement, as shown in FIG. Attenuator 32, optical power meter 33, optical oscilloscope 34, control equipment 35;

The control device 35 is used to adjust the adjustable attenuator 32 to measure the receiving sensitivity of the optical module 30 to be tested, and record the receiving sensitivity measured by the optical power meter 33 as the first power; Adjustable attenuator 32, after the input optical power input to the receiving end of the optical module 30 to be tested reaches a predetermined power range, record the input optical power measured by the optical power meter 33 as the second power, and from the The optical oscilloscope 34 obtains the second optical modulation amplitude; the second optical modulation amplitude is divided by the second power, and multiplied by the first power to obtain the first optical modulation amplitude in the receiving sensitivity measurement.

In other embodiments, all or part of the operations of the control device 35 may also be performed by humans.

Optionally, the predetermined power interval is the power measurement range of the optical oscilloscope;

Alternatively, the predetermined power interval is within the power measurement range of the optical oscilloscope.

Optionally, the test system also includes:

A bit error analyzer for measuring the bit error rate of the optical module to be tested;

The control device used to adjust the adjustable attenuator to measure the receiving sensitivity of the optical module under test includes:

The control device adjusts the adjustable attenuator so that the input optical power input to the receiving end of the optical module under test changes from large to small until the bit error rate measured by the bit error analyzer reaches When the first predetermined threshold is reached, the input optical power of the receiving end of the optical module under test measured by the optical power meter is recorded to obtain the receiving sensitivity of the optical module under test.

Optionally, the control device divides the second optical modulation amplitude by the second power, and multiplies the second optical modulation amplitude by the first power to obtain the first optical modulation amplitude in the receiving sensitivity measurement including:

The control device converts the first power, the second power, and the second optical modulation amplitude into corresponding decibel milliwatts; after conversion, the second optical modulation amplitude is subtracted from the power difference to obtain the first optical modulation amplitude in the receiving sensitivity measurement. an optical modulation amplitude; the power difference is the second power minus the first power.

For other implementation details, refer to Embodiment 1.

Those skilled in the art can understand that all or part of the steps in the above method can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a magnetic disk or an optical disk, and the like. Optionally, all or part of the steps in the foregoing embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the foregoing embodiments may be implemented in the form of hardware, or may be implemented in the form of software function modules. The present invention is not limited to any specific combination of hardware and software.

Although the embodiments disclosed in the present invention are as above, the described content is only an embodiment adopted for understanding the present invention, and is not intended to limit the present invention. Anyone skilled in the field of the present invention can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed by the present invention, but the patent protection scope of the present invention must still be The scope defined by the appended claims shall prevail.

Claims (10)

1. A test method for optical modulation amplitude value in receiving sensitivity measurement, comprising: Measuring the receiving sensitivity of the optical module to be tested, and recording the receiving sensitivity as the first power; After adjusting the input optical power input to the receiving end of the optical module to be tested to within a predetermined power range, record the input optical power as the second power, and measure the second optical modulation amplitude; The second light modulation amplitude is divided by the second power, and multiplied by the first power to obtain the first light modulation amplitude in receiving sensitivity measurement. 2. The test method according to claim 1, wherein said measuring the second light modulation amplitude comprises: Using an optical oscilloscope to measure the optical modulation amplitude of the receiving end of the optical module to be tested as the second optical modulation amplitude. 3. testing method as claimed in claim 2, is characterized in that: The predetermined power interval is the power measurement range of the optical oscilloscope; Alternatively, the predetermined power interval is within the power measurement range of the optical oscilloscope. 4. The testing method according to claim 1, wherein said measuring the receiving sensitivity of the optical module to be tested comprises: Adjust the input optical power input to the receiving end of the optical module under test in a descending manner, until the bit error rate of the optical module under test reaches a first predetermined threshold, use an optical power meter to measure the optical power under test The input optical power of the receiving end of the module is used to obtain the receiving sensitivity of the optical module to be tested. 5. The test method according to any one of claims 1 to 4, wherein said adjusting the input optical power input to the receiving end of the optical module to be tested comprises: Adjusting the adjustable attenuator arranged between the sending end of the reference transmitter and the receiving end of the optical module under test to increase or decrease the input optical power input to the receiving end of the optical module under test. 6. The test method according to any one of claims 1 to 4, wherein said second optical modulation amplitude is divided by the second power and multiplied by the first power to obtain the first value in the receiving sensitivity measurement. A light modulation amplitude includes: converting the first power, the second power, and the second optical modulation amplitude into corresponding decibel milliwatts; After the conversion, subtract the power difference from the second light modulation amplitude to obtain the first light modulation amplitude in receiving sensitivity measurement; the power difference is the second power minus the first power. 7. A test system for the optical modulation amplitude value in receiving sensitivity measurement, characterized in that it comprises: a reference transmitter, an adjustable attenuator arranged between the reference transmitter sending end and the receiving end of the optical module to be tested, an optical power meter, optical oscilloscope, control equipment; The control device is used to adjust the adjustable attenuator to measure the receiving sensitivity of the optical module to be tested, and record the receiving sensitivity measured by the optical power meter as the first power; for adjusting the adjustable attenuator After the input optical power input to the receiving end of the optical module to be tested falls within a predetermined power range, the input optical power measured by the optical power meter is recorded as the second power, and the second optical power is obtained from the optical oscilloscope. Modulation amplitude: dividing the second optical modulation amplitude by the second power and multiplying by the first power to obtain the first optical modulation amplitude in receiving sensitivity measurement. 8. The test system as claimed in claim 7, characterized in that: The predetermined power interval is the power measurement range of the optical oscilloscope; Alternatively, the predetermined power interval is within the power measurement range of the optical oscilloscope. 9. The test system according to claim 7, further comprising: A bit error analyzer for measuring the bit error rate of the optical module to be tested; The control device used to adjust the adjustable attenuator to measure the receiving sensitivity of the optical module under test includes: The control device adjusts the adjustable attenuator so that the input optical power input to the receiving end of the optical module under test changes from large to small until the bit error rate measured by the bit error analyzer reaches When the first predetermined threshold is reached, the input optical power of the receiving end of the optical module under test measured by the optical power meter is recorded to obtain the receiving sensitivity of the optical module under test. 10. The test system according to any one of claims 7 to 9, wherein the control device divides the second optical modulation amplitude by the second power and multiplies it by the first power to obtain The amplitude of the first optical modulation consists of: The control device converts the first power, the second power, and the second optical modulation amplitude into corresponding decibel milliwatts; after conversion, the second optical modulation amplitude is subtracted from the power difference to obtain the first optical modulation amplitude in the receiving sensitivity measurement. an optical modulation amplitude; the power difference is the second power minus the first power.