Pluggable optical module automatic gain control method and system and dual-path output peak detection circuit

Abstract

The invention relates to the technical field of communication, in particular to a pluggable optical module automatic gain control method and system and a double-path output peak detection circuit, and the method comprises the steps: configuring and initializing a double-path peak detection device in an optical module; inserting the optical module into a target port, and obtaining a peak value of the double-path peak value detection device under a preset frequency; calculating an insertion loss value according to the peak value under the preset frequency; calculating an AGC target value of the target port based on the insertion loss value; and adjusting the gain of the linear driver by taking the matching AGC target value as a target. The objective of the invention is to dynamically adjust the gain of the linear driver and improve the consistency of the extinction ratio of each port.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a pluggable optical module automatic gain control method, system and a dual-channel output peak detection circuit. Background Art

[0002] In the current data center architecture, with the development of supercomputing and artificial intelligence (AI) technology, the demand for high bandwidth is growing. This has driven data center operators to move towards higher density, lower latency and more energy-efficient network solutions. In this context, low-power pluggable optical (LPO) transceivers have attracted widespread attention due to their advantages of low power consumption, low cost and low latency. However, as the port density of high-speed switches used in data centers continues to increase, the requirements for LPO modules are also increasing. Since a single switch is usually equipped with only one serializer / deserializer (SerDes) chip, the increase in port density will cause significant changes in the electrical insertion loss (IL) between different ports. Ports close to the center of the switch usually have shorter radio frequency (RF) traces, resulting in lower insertion loss; on the contrary, ports at the edge have higher insertion loss due to longer RF traces. This change in insertion loss will cause the same input signal to produce different output amplitudes at different ports, thereby affecting the extinction ratio (ER) in the optical domain. In particular, high insertion loss (HL) ports may fail to meet communication standards due to insufficient extinction ratio, which in turn affects the decision performance of the receiving end. In view of this, when the LPO module is inserted into ports with different insertion loss characteristics, if the gain of the linear driver is fixed, it will lead to inconsistency in the output signal amplitude between the ports.

[0003] At present, a common way to implement the automatic gain control (AGC) function is to monitor the output signal strength of the linear driver through a single peak detection (PKD) circuit. In specific implementation, a high-frequency PKD circuit is used to detect the signal strength at the output of the driver, and then the microcontroller unit (MCU) reads these PKD values ​​in real time and dynamically adjusts the gain of the driver accordingly to maintain the stability of the PKD value, thereby ensuring the consistency of the driver output.

[0004] However, this method has certain limitations. In order to ensure that the PKD circuit can detect sufficient signal strength, most drivers usually set the PKD detection bandwidth to 20GHz. However, insertion loss has different effects on high-frequency and low-frequency signals: high-frequency signals often suffer greater attenuation than low-frequency signals. In a high-speed data transmission environment, the signal contains multiple components from low frequency to high frequency. Therefore, relying solely on the PKD value of the high frequency band (such as 20GHz) cannot accurately reflect the actual insertion loss. This means that if the AGC system simply relies on the PKD value of 20GHz to adjust the gain, then when facing ports with different insertion loss characteristics, the extinction ratio (ER) of the system may still show significant differences. As a result, under different insertion loss conditions, even after AGC adjustment, the signal quality still cannot achieve ideal consistency. Summary of the invention

[0005] In order to dynamically adjust the gain of the linear driver and improve the consistency of the extinction ratio of each port, the present invention provides a pluggable optical module automatic gain control method, system and dual-output peak detection circuit. The technical solutions adopted are as follows:

[0006] The technical solution of the first aspect of the present invention provides a pluggable optical module automatic gain control method, the method comprising:

[0007] A dual-path peak detection device is configured and initialized in the optical module;

[0008] Insert the optical module into the target port to obtain the peak value of the dual-channel peak detection device at a preset frequency;

[0009] Calculate the insertion loss value based on the peak value at the preset frequency;

[0010] Calculate the AGC target value of the target port based on the insertion loss value;

[0011] The gain of the linear driver is adjusted to match the AGC target value.

[0012] Further, configuring and initializing a dual-path peak detection device in the optical module includes:

[0013] The dual-path peak detection device comprises a first peak detection unit and a second peak detection unit, wherein the first peak detection unit is used to detect low-frequency signals, and the second peak detection unit is used to detect high-frequency signals.

[0014] Furthermore, the filter frequency of the first peak detection unit is 20 GHz.

[0015] Furthermore, the filter frequency of the second peak detection unit is 1 GHz.

[0016] Further, the insertion loss value is calculated according to the peak value at the preset frequency, including:

[0017] The insertion loss value is calculated based on the signal peak detection value at 20 GHz frequency and the signal peak detection value at 1 GHz frequency.

[0018] Furthermore, the expression for calculating the insertion loss value based on the signal peak detection value at 20 GHz frequency and the signal peak detection value at 1 GHz frequency is:

[0019]

[0020] Wherein, IL represents the insertion loss value; 20G PKD represents the signal peak detection value at 20 GHz frequency; 1G PKD represents the signal peak detection value at 1 GHz frequency.

[0021] Further, the AGC target value of the target port is calculated based on the insertion loss value, including:

[0022] The AGC target value of the target port is calculated based on the preset AGC reference value and insertion loss value. The expression is:

[0023] AGC target =AGC ref ×(1+k·IL)

[0024] Where, AGC target Indicates the AGC target value; AGC ref represents the AGC reference value; k represents the preset coefficient; IL represents the insertion loss value.

[0025] Further, the gain of the linear driver is adjusted to match the AGC target value, including:

[0026] Based on the AGC target value, the gain of the linear driver is adjusted and repeatedly adjusted through continuous peak detection and feedback mechanism until the actual gain matches the AGC target value.

[0027] The technical solution of the second aspect of the present invention provides a dual-output peak detection circuit, the detection circuit includes a photoelectric converter, a high-frequency peak detection circuit, and a low-frequency peak detection circuit, the high-frequency peak detection circuit and the low-frequency peak detection circuit are electrically connected to the output end of the photoelectric converter, respectively, the low-frequency peak detection circuit is configured with a first resistor, a second resistor, a first capacitor, a second capacitor and a first detection chip, the first resistor, the second resistor, the first capacitor and the second capacitor constitute a low-pass filter, the first detection chip is configured to output a low-frequency peak under a 1G Hz low-frequency signal; the high-frequency peak detection circuit is configured with a third resistor, a fourth resistor, a third capacitor, a fourth capacitor and a second detection chip, the third resistor, the fourth resistor, the third capacitor and the fourth capacitor constitute a band-pass filter, and the second detection chip is configured to output a high-frequency peak under a 20G Hz high-frequency signal.

[0028] The technical solution of the third aspect of the present invention provides a pluggable optical module automatic gain control system, the system comprising:

[0029] A dual-path peak detection module configured to obtain a peak value at a preset frequency;

[0030] The insertion loss value calculation module is configured to calculate the insertion loss value according to the peak value at a preset frequency, and its expression is:

[0031]

[0032] Where, IL represents the insertion loss value; 20G PKD represents the signal peak detection value at 20GHz frequency; 1G PKD represents the signal peak detection value at 1GHz frequency;

[0033] The AGC target value calculation module is configured to calculate the AGC target value of the target port based on the insertion loss value, and its expression is:

[0034] AGC target =AGC ref ×(1+k·IL)

[0035] Where, AGC target Indicates the AGC target value; AGC ref Indicates the AGC reference value; k indicates the preset coefficient; IL indicates the insertion loss value;

[0036] The control module is configured to adjust the gain of the linear driver to match the AGC target value.

[0037] The present invention has the following beneficial effects:

[0038] The pluggable optical module automatic gain control method, system and dual-channel output peak detection circuit provided by the present invention integrate a dual-channel peak detection device inside the optical module to detect the peak values ​​of high-frequency and low-frequency signals respectively, calculate the insertion loss value and the AGC target value based on the peak values ​​detected by the dual-channel peak detection device, and finally adjust the gain of the linear driver with the goal of matching the AGC target value. Whether in a low insertion loss or high insertion loss environment, the signal attenuation caused by the insertion loss can be compensated by adjusting the gain, thereby improving the consistency of the extinction ratio of each channel of the pluggable optical module. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 A method flow chart of a pluggable optical module automatic gain control method provided by one embodiment of the present invention;

[0041] Figure 2 A schematic diagram of the structure of a dual-output peak detection circuit provided by an embodiment of the present invention;

[0042] Figure 3 A schematic diagram of the structure of a pluggable optical module automatic gain control system provided by an embodiment of the present invention;

[0043] Figure 4 A schematic diagram of extinction ratio data of all ports of a switch after using the pluggable optical module automatic gain control method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the pluggable optical module automatic gain control method, system and dual-output peak detection circuit proposed by the present invention, its specific implementation method, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0045] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0046] The following specifically describes a pluggable optical module automatic gain control method, system and dual-output peak detection circuit provided by the present invention in conjunction with the accompanying drawings.

[0047] See also Figure 1 , which shows a method flow chart of a pluggable optical module automatic gain control method provided by an embodiment of the present invention. The technical solution of the first aspect of the present invention provides a pluggable optical module automatic gain control method, and the method includes:

[0048] Step S100: configuring and initializing a dual-path peak detection device in the optical module; specifically, in the field of optical communications, especially in the design and application of pluggable optical modules, automatic gain control (AGC) is a key technical link, and the main function of AGC is to ensure that the power of the output signal can remain constant under different insertion loss (IL) conditions, thereby ensuring the integrity of the signal; the dual-path peak detection device includes a first peak detection unit and a second peak detection unit, the first peak detection unit is used to detect low-frequency signals, and the second peak detection unit is used to detect high-frequency signals, the filter frequency of the first peak detection unit is 20 GHz, and the filter frequency of the second peak detection unit is 1 GHz.

[0049] Step S200: insert the optical module into the target port, and obtain the peak value of the dual-channel peak detection device at a preset frequency; specifically, insert the optical module into the target port of the network device and ensure that the electrical connection between the optical module and the port is normal; then the dual-channel peak detection device starts to work, the first peak detection unit is responsible for detecting the peak value under the high-frequency signal (20 GHz), and the second peak detection unit is responsible for detecting the peak value under the low-frequency signal (1 GHz);

[0050] Step S300: calculating the insertion loss value according to the peak value at a preset frequency;

[0051] Step S300 specifically includes:

[0052] Step S310: Calculate the insertion loss value based on the signal peak detection value at 20 GHz frequency and the signal peak detection value at 1 GHz frequency, and the expression is:

[0053]

[0054] In the formula, IL represents the insertion loss value; 20G PKD represents the signal peak detection value at a frequency of 20 GHz; 1G PKD represents the signal peak detection value at a frequency of 1 GHz; specifically, at high frequencies, the signal is more susceptible to the loss on the transmission path, that is, the insertion loss is larger; at low frequencies, the signal is less susceptible to loss, and the insertion loss is relatively small; the insertion loss value reflects the attenuation of the high-frequency signal relative to its own strength. Since the 1G PKD value in the numerator is relatively stable when the insertion loss changes, this ratio can better reflect the change in insertion loss; this embodiment judges the insertion loss according to the peak difference between the high-frequency and low-frequency signals, and adjusts the gain of the driver accordingly to ensure that consistent signal quality can be obtained under different insertion loss conditions;

[0055] Step S400: Calculating the AGC target value of the target port based on the insertion loss value;

[0056] Step S400 specifically includes:

[0057] Step S410: Calculate the AGC target value of the target port according to the preset AGC reference value and insertion loss value, and the expression is:

[0058] AGC target =AGC ref ×(1+k·IL)

[0059] Where, AGC target Indicates the AGC target value; AGC ref represents the AGC reference value; k represents the preset coefficient; IL represents the insertion loss value; specifically, in practical applications, AGC ref It can be the optimal gain value determined in advance through testing, and the k value can be obtained by fitting experimental data. Therefore, for different brands of switches, only different k values ​​need to be written to adapt to different switches. Ultimately, whether in the case of low insertion loss or high insertion loss, the consistency of the output signal can be maintained by dynamically adjusting the gain;

[0060] Step S500: adjusting the gain of the linear driver to match the AGC target value;

[0061] Step S500 specifically includes:

[0062] Step S510: Based on the AGC target value, adjust the gain of the linear driver, and repeatedly adjust it through continuous peak detection and feedback mechanism until the actual gain matches the AGC target value; specifically, according to the AGC target , adjust the gain of the linear driver through the control signal, and send an adjustment command to the optical module driver to make its gain setting connected to the AGC targetThen start the dual peak detection device again to continuously monitor the peak values ​​of the high-frequency and low-frequency signals, and compare the new peak detection results with the AGC target If the actual gain does not match the target value, the AGC is gradually approached through continuous peak detection and feedback adjustment. target , until the actual gain matches the target value; in this embodiment, since the AGC target value is dynamically adjusted according to the insertion loss value, it can avoid the phenomenon that the fixed AGC target value has inconsistent extinction ratios at different insertion loss ports, and automatically adapt to different insertion loss environments without manual intervention, thereby making the extinction ratios of various ports basically consistent; please refer to Figure 4 , Figure 4 The data diagram of the extinction ratio of all ports of a switch after using the automatic gain control method of the pluggable optical module is recorded in Figure 4 The CH1-CH8 in the figure represent different channel ports. Figure 4 It can be seen that after the switch adopts the pluggable optical module automatic gain control method provided in this embodiment, the extinction ratio error of each channel of the same LPO module on all ports of the switch can be kept within 1dB, and the extinction ratio values ​​of all ports are greater than 3.5dB, meeting the protocol requirements.

[0063] See also Figure 2 , which shows a schematic diagram of the structure of a dual-output peak detection circuit provided by an embodiment of the present invention. The technical solution of the second aspect of the present invention provides a dual-output peak detection circuit, the detection circuit includes a photoelectric converter, a high-frequency peak detection circuit, and a low-frequency peak detection circuit, the high-frequency peak detection circuit and the low-frequency peak detection circuit are electrically connected to the output end of the photoelectric converter respectively; the low-frequency peak detection circuit is configured with a first resistor, a second resistor, a first capacitor, a second capacitor and a first detection chip, the first resistor, the second resistor, the first capacitor and the second capacitor constitute a low-pass filter, and the first detection chip is configured to detect a low-frequency peak under a 1G Hz low-frequency signal; the high-frequency peak detection circuit is configured with a third resistor, a fourth resistor, a third capacitor, a fourth capacitor and a second detection chip, the third resistor, the fourth resistor, the third capacitor and the fourth capacitor constitute a band-pass filter, and the second detection chip is configured to detect a high-frequency peak under a 20G Hz high-frequency signal; specifically, the photoelectric converter is used to convert the received optical signal into an electrical signal, and output it to a subsequent peak detection circuit;

[0064] The first resistor and the second resistor are arranged in parallel, one end of the first resistor is connected to the first output terminal of the photoelectric converter, the other end of the first resistor is connected to the first detection chip, the first capacitor is arranged between the first resistor and the first detection chip, and one end of the first capacitor is grounded; one end of the second resistor is connected to the second output terminal of the photoelectric converter, the other end of the second resistor is connected to the first detection chip, the second capacitor is arranged between the second resistor and the first detection chip, and one end of the second capacitor is grounded; one end of the third resistor is connected to the first output terminal of the photoelectric converter, the other end of the third resistor is connected to the second detection chip, the third capacitor is arranged between the third resistor and the second detection chip, and one end of the third capacitor is grounded; one end of the fourth resistor is connected to the second output terminal of the photoelectric converter, the other end of the fourth resistor is connected to the second detection chip, the fourth capacitor is arranged between the fourth resistor and the second detection chip, and one end of the fourth resistor is grounded; wherein the high-frequency peak detection circuit allows high-frequency signals near 20 GHz to pass through, while suppressing signals below 1 GHz and above 20 GHz, so that the output of the 20G PKD circuit becomes the high-frequency peak of the signal; the low-frequency peak detection circuit allows low-frequency signals near 1 GHz to pass through, suppresses high-frequency signals above 1 GHz, so that 1G The output of the PKD circuit becomes the low-frequency peak of the signal; the outputs of the low-frequency peak detection loop and the high-frequency peak detection loop are sent to the microcontroller unit for processing. The MCU calculates the insertion loss based on these two output values ​​and adjusts the gain of the linear driver accordingly.

[0065] By using this dual-channel output peak detection circuit, the high-frequency PKD and low-frequency PKD of the output signal of the port with different insertion losses can be detected respectively, and then the insertion loss values ​​of different ports can be characterized according to the data rules of the PKD values ​​of different frequencies at different insertion loss ports, as shown in Table 1:

[0066]

[0067]

[0068] Table 1: High-frequency PKD test values ​​and low-frequency PKD test values ​​corresponding to different insertion losses of a switch

[0069] Table 1 records the experimental data of a switch under different insertion loss ports while keeping the extinction ratio consistent. According to Table 1, the reading of 1G PKD basically does not change with the change of insertion loss, the reading of 20G PKD decreases with the increase of insertion loss, and the ratio of 1G PKD to 20G PKD readings increases with the increase of insertion loss, so it can be used as a representation value of the insertion loss size.

[0070] See also Figure 3, which shows a schematic diagram of the structure of a pluggable optical module automatic gain control system provided by an embodiment of the present invention. The technical solution of the third aspect of the present invention provides a pluggable optical module automatic gain control system, the system comprising:

[0071] A dual-path peak detection module configured to obtain a peak value at a preset frequency;

[0072] The insertion loss value calculation module is configured to calculate the insertion loss value according to the peak value at a preset frequency, and its expression is:

[0073]

[0074] Where, IL represents the insertion loss value; 20G PKD represents the signal peak detection value at 20GHz frequency; 1G PKD represents the signal peak detection value at 1GHz frequency;

[0075] The AGC target value calculation module is configured to calculate the AGC target value of the target port based on the insertion loss value, and its expression is:

[0076] AGC target =AGC ref ×(1+k·IL)

[0077] Where, AGC target Indicates the AGC target value; AGC ref Indicates the AGC reference value; k indicates the preset coefficient; IL indicates the insertion loss value;

[0078] The control module is configured to adjust the gain of the linear driver to match the AGC target value.

[0079] It should be noted that the sequence of the above embodiments of the present invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0080] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. Automatic gain control method for pluggable optical modules, It is characterized in that The method comprises: A dual-path peak detection device is configured and initialized in the optical module; Insert the optical module into the target port to obtain the peak value of the dual-channel peak detection device at a preset frequency; Calculate the insertion loss value based on the peak value at the preset frequency; Calculate the AGC target value of the target port based on the insertion loss value; The gain of the linear driver is adjusted to match the AGC target value.

2. The automatic gain control method for a pluggable optical module according to claim 1, It is characterized in that Configuring and initializing a dual-path peak detection device in an optical module includes: The dual-path peak detection device comprises a first peak detection unit and a second peak detection unit, wherein the first peak detection unit is used to detect low-frequency signals, and the second peak detection unit is used to detect high-frequency signals.

3. The automatic gain control method for a pluggable optical module according to claim 2, It is characterized in that The filter frequency of the first peak detection unit is 20 GHz.

4. The automatic gain control method for a pluggable optical module according to claim 3, It is characterized in that The filter frequency of the second peak detection unit is 1 GHz.

5. The automatic gain control method for a pluggable optical module according to claim 4, It is characterized in that Insertion loss is calculated based on the peak value at the preset frequency, including: The insertion loss value is calculated based on the signal peak detection value at 20 GHz frequency and the signal peak detection value at 1 GHz frequency.

6. The automatic gain control method for a pluggable optical module according to claim 5, It is characterized in that The expression for calculating the insertion loss value based on the signal peak detection value at 20 GHz frequency and the signal peak detection value at 1 GHz frequency is: Wherein, IL represents the insertion loss value; 20G PKD represents the signal peak detection value at 20 GHz frequency; 1G PKD represents the signal peak detection value at 1 GHz frequency.

7. The automatic gain control method for a pluggable optical module according to any one of claims 1 to 6, It is characterized in that Calculate the AGC target value of the target port based on the insertion loss value, including: The AGC target value of the target port is calculated based on the preset AGC reference value and insertion loss value. The expression is: AGC target =AGC ref ×(1+k·IL) Where, AGC target Indicates the AGC target value; AGC ref represents the AGC reference value; k represents the preset coefficient; IL represents the insertion loss value.

8. The automatic gain control method for a pluggable optical module according to claim 7, It is characterized in that Adjust the linear driver gain to match the AGC target value, including: Based on the AGC target value, the gain of the linear driver is adjusted and repeatedly adjusted through continuous peak detection and feedback mechanism until the actual gain matches the AGC target value.

9. Dual output peak detection circuit, It is characterized in that The detection circuit includes a photoelectric converter, a high-frequency peak detection circuit, and a low-frequency peak detection circuit. The high-frequency peak detection circuit and the low-frequency peak detection circuit are electrically connected to the output end of the photoelectric converter, respectively. The low-frequency peak detection circuit is configured with a first resistor, a second resistor, a first capacitor, a second capacitor, and a first detection chip. The first resistor, the second resistor, the first capacitor, and the second capacitor constitute a low-pass filter. The first detection chip is configured to output a low-frequency peak under a 1 GHz low-frequency signal; the high-frequency peak detection circuit is configured with a third resistor, a fourth resistor, a third capacitor, a fourth capacitor, and a second detection chip. The third resistor, the fourth resistor, the third capacitor, and the fourth capacitor constitute a band-pass filter. The second detection chip is configured to output a high-frequency peak under a 20 GHz high-frequency signal.

10. Automatic gain control system for pluggable optical modules, It is characterized in that The system comprises: A dual-path peak detection module configured to obtain a peak value at a preset frequency; The insertion loss value calculation module is configured to calculate the insertion loss value according to the peak value at a preset frequency, and its expression is: Where, IL represents the insertion loss value; 20G PKD represents the signal peak detection value at 20GHz frequency; 1G PKD represents the signal peak detection value at 1GHz frequency; The AGC target value calculation module is configured to calculate the AGC target value of the target port based on the insertion loss value, and its expression is: AGC target =AGC ref ×(1+k·IL) Where, AGC target Indicates the AGC target value; AGC ref Indicates the AGC reference value; k indicates the preset coefficient; IL indicates the insertion loss value; The control module is configured to adjust the gain of the linear driver to match the AGC target value.

Images