WO2023169296A1

WO2023169296A1 - Optical power control method and apparatus

Info

Publication number: WO2023169296A1
Application number: PCT/CN2023/079273
Authority: WO
Inventors: 王旭; 吴奇宏; 冀瑞强
Original assignee: 华为技术有限公司
Priority date: 2022-03-07
Filing date: 2023-03-02
Publication date: 2023-09-14
Also published as: CN116782062A

Abstract

Embodiments of the present application provide an optical power control apparatus and method. The optical power control apparatus comprises a power detector, an electric driver, and an adjustable optical attenuator. The power detector is used to generate a first electrical signal and a first optical signal on the basis of an input optical signal, output the first electrical signal from a second port of the power detector, and output the first optical signal from a third port of the power detector. The electrical driver is used to determine an attenuation value of the adjustable optical attenuator according to the first electrical signal obtained from the electrical driver, and a second port of the electrical driver is connected to a first port of the adjustable optical attenuator. The adjustable optical attenuator is used to receive a first optical signal from the second port of the adjustable optical attenuator, generate a second optical signal on the basis of the first optical signal and the attenuation value, and output the second optical signal from a third port of the adjustable optical attenuator. The present optical power control apparatus can achieve the effect of strong attenuation for strong light and weak attenuation or no attenuation for weak light can be achieved, effectively controlling an optical power range of a receiver.

Description

Optical power control method and device

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on March 7, 2022, with application number 202210221977.0 and the application title "Optical Power Control Method and Device", the entire content of which is incorporated into this application by reference. middle.

Technical field

The present application relates to the field of optical communications, and more specifically, to an optical power control method and device.

Background technique

With the rapid development of high-speed and large-capacity optical communication technology, passive optical network (PON) is widely used in optical access networks because of its characteristics of saving optical fiber resources, easy maintenance, and easy expansion. PON consists of an optical line terminal (OLT) at the central office, an optical network unit (ONU) at the user side, and an optical distribution network (ODN).

Different ONUs burst uplink data to the OLT in time-divided time slots. Correspondingly, OLT needs to receive and process a large optical dynamic range, which requires high performance of electrical devices. In addition, since each channel has a large dynamic range of received light, large optical links will cause strong interference to small optical links, which will lead to crosstalk of each channel and deterioration of the receiving sensitivity of each channel. Therefore, how to effectively control the optical power dynamic range of OLT is an issue that needs to be solved urgently.

Contents of the invention

Embodiments of the present application provide an optical power control method and device that can effectively control the optical power dynamic range of an OLT.

In a first aspect, an optical power control device is provided. Optical power control devices include power detectors, electric drivers and adjustable optical attenuators. The power detector is configured to generate a first electrical signal and a first optical signal based on the input optical signal, and output the first electrical signal from the second port of the power detector and the first optical signal from the third port of the power detector. The electric driver is used to determine the attenuation value of the adjustable light attenuator according to the first electrical signal obtained from the electric driver, and the second port of the electric driver is connected to the first port of the adjustable light attenuator. The adjustable optical attenuator is used for receiving a first optical signal from the second port of the adjustable optical attenuator, and generating a second optical signal based on the first optical signal and the attenuation value, and is also used for receiving the first optical signal from the third port of the adjustable optical attenuator. Output the second optical signal.

Based on the above solution, the optical power control device can achieve strong attenuation when the input optical signal power is large, and weak attenuation or no attenuation when the input optical signal power is small, effectively controlling the dynamic range of the received optical power.

It should be understood that the second port of the electric driver is connected to the first port of the adjustable optical attenuator for transmitting the electric driving signal, and the electric driving signal is determined based on the attenuation value.

In conjunction with the first aspect, in some implementations of the first aspect, the power detector is an optical power monitor.

In conjunction with the first aspect, in some implementations of the first aspect, the power detector includes a beam splitter and a photodetector. The optical splitter is configured to generate a first optical signal and a third optical signal based on the input optical signal, output the third optical signal from the second port of the optical splitter, and output the first optical signal from the third port of the optical splitter. The photodetector is configured to generate a first electrical signal according to the received third optical signal and output the first electrical signal from the second port of the photodetector.

In connection with the first aspect, in some implementations of the first aspect, the electric driver is a comparator. The comparator pre-stores a first threshold value, and the first threshold value is used for comparison with the first electrical signal. The comparator is configured to compare the first threshold value and the first electrical signal according to the The attenuation value of the adjustable light attenuator is determined, and whether to generate an electric drive signal is determined based on the attenuation value.

In connection with the first aspect, in some implementations of the first aspect, the electric driver includes an amplifier and a comparator. The first port of the amplifier is connected to the second port of the power detector, and is used to amplify the first electrical signal to generate a second electrical signal. The first port of the comparator is connected to the second port of the amplifier, the second port of the comparator is connected to the first port of the adjustable optical attenuator, the comparator pre-stores a first threshold, and the first threshold is used to interact with the second electrical signal. Compare. The comparator is used to determine the attenuation value of the adjustable optical attenuator according to the comparison result of the first threshold value and the second electrical signal, and is also used to determine whether to generate an electric driving signal according to the attenuation value.

In connection with the first aspect, in some implementations of the first aspect, the electric driver is an amplifier. The amplifier is used to amplify the first electrical signal, determine an attenuation value of the adjustable optical attenuator based on the amplified electrical signal, and generate an electric drive signal according to the attenuation value.

Combined with the first aspect, in some implementations of the first aspect, the adjustable optical attenuator is a Mach Zehnder interferometer (MZI) optical attenuator, a micro-electro-mechanical system (MEMS) ) technology variable optical attenuator or film type optical attenuator.

In the second aspect, an optical power control method is provided. The optical power control method includes: receiving an input optical signal, generating a first electrical signal and a first optical signal based on the input optical signal, and obtaining an attenuation value. The attenuation value is obtained based on the first electrical signal. According to the attenuation value and the first optical signal Generate a second optical signal and output the second optical signal.

Based on the above solution, the optical power control device can achieve strong attenuation for large input optical signal powers, weak attenuation or no attenuation for small input optical signal powers, and effectively control the dynamic range of received optical power.

In conjunction with the second aspect, in some implementations of the second aspect, whether to generate an electric drive signal is determined based on the attenuation value, and the electric drive signal is used to perform power adjustment on the first optical signal.

In this implementation, the attenuation value is used to determine whether to generate an electric drive signal, thereby realizing power adjustment of the first optical signal and effectively controlling the dynamic range of the received optical power.

In conjunction with the second aspect, in some implementations of the second aspect, generating the first electrical signal based on the input optical signal includes: performing power detection on the input optical signal to generate the first electrical signal.

In conjunction with the second aspect, in some implementations of the second aspect, generating the first electrical signal and the first optical signal based on the input optical signal includes: splitting the input optical signal to generate a third optical signal and the first optical signal. signal, performing power detection on the third optical signal to generate a first electrical signal.

In conjunction with the second aspect, in some implementations of the second aspect, determining whether to generate an electric drive signal based on the attenuation value includes: when the first electrical signal is greater than the first threshold, determining to generate the electric drive signal based on the attenuation value. Alternatively, when the first electrical signal is less than the first threshold, it is determined according to the attenuation value that the electrical drive signal is not generated or that the electrical drive signal is a fixed value.

In this implementation, the relationship between the first electrical signal and the first threshold is judged based on the digital circuit method, and it is determined whether to generate the electrical drive signal, that is, the attenuation value and the electrical drive signal are controlled by the first electrical signal, thereby achieving control of the received light. Efficient control of the dynamic range of power.

In connection with the second aspect, in some implementations of the second aspect, determining whether to generate an electric drive signal according to the attenuation value includes: amplifying the first electric signal to generate a second electric signal. When the second electric signal is greater than the first electric signal, When a threshold is reached, the electric drive signal is generated based on the attenuation value. Alternatively, when the second electrical signal is less than the first threshold, it is determined according to the attenuation value that the electrical drive signal is not generated or that the electrical drive signal is a fixed value.

In this implementation, the relationship between the second electrical signal and the first threshold is judged based on the digital circuit method, and it is determined whether to generate the electrical drive signal, that is, the attenuation value and the electrical drive signal are controlled by the second electrical signal, thereby achieving control of the received light. Efficient control of the dynamic range of power.

Combined with the second aspect, in some implementations of the second aspect, the first electrical signal is amplified to generate an electric drive Signal. In this implementation, the first electrical signal is amplified based on the analog circuit method to generate an electrical drive signal, which can realize continuous adjustment of the input optical power.

In connection with the second aspect, in some implementations of the second aspect, generating a second optical signal according to the attenuation value and the first optical signal includes: determining and generating an electric drive signal according to the attenuation value, and adjusting the first optical signal according to the electric drive signal. power to generate a second optical signal. In this implementation, the attenuation value is used to control the output of the electric drive signal, and then adjust the power of the first optical signal to achieve dynamic attenuation of the received optical power.

In a third aspect, an optical line terminal OLT is provided. The OLT includes a photodetector, a trans-impedance amplifier (TIA) and an optical power control device. The photodetector is connected to the third port of the adjustable light attenuator and is used for photoelectric conversion of the second optical signal to generate a third electrical signal. The TIA is connected to the photodetector and is used to amplify the third electrical signal to generate an output electrical signal. The optical power control device is used to perform the method in the above second aspect or any possible implementation manner of the second aspect.

The fourth aspect provides a passive optical network system. The passive optical network system includes ONU, ODN and OLT. The ONU is used to send input optical signals to the ODN. ODN is used to transmit the input optical signal received from the ONU to the OLT. OLT is used to receive input optical signals.

Description of the drawings

Figure 1 is a schematic structural diagram of a traditional OLT.

Figure 2 is a schematic structural diagram of the first OLT provided by the embodiment of the present application.

FIG. 3 is a schematic structural diagram of two implementation methods of the power detector provided by the embodiment of the present application.

Figure 4 is a schematic structural diagram of two implementation methods of the electric driver provided by the embodiment of the present application.

Figure 5 is a schematic flowchart of an optical power control method provided by an embodiment of the present application.

Figure 6 is a schematic structural diagram of a second OLT provided by an embodiment of the present application.

FIG. 7 is a schematic diagram of the first correspondence between output optical power and input optical power provided by an embodiment of the present application.

Figure 8 is a schematic structural diagram of a third OLT provided by an embodiment of the present application.

FIG. 9 is a schematic diagram of the second correspondence between output optical power and input optical power provided by the embodiment of the present application.

Figure 10 is a schematic structural diagram of a fourth OLT provided by an embodiment of the present application.

Figure 11 is a schematic structural diagram of a passive optical network system provided by an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

Optical fiber access network refers to an application form that uses optical fiber as the main transmission medium in the access network to realize user information transmission, or an access method that uses optical fiber communication or partially uses optical fiber communication between business nodes and users. With the continuous development of communication technology, PON plays an increasingly important role in optical fiber access networks with its characteristics of saving optical fiber resources, being transparent to network protocols, easy to maintain, and easy to expand.

PON is generally composed of OLT, ODN and multiple ONUs. Among them, OLT is the terminal equipment used to connect optical fiber trunk lines. The OLT is generally placed at the central office and provides an optical fiber interface for the user-side passive optical fiber network. OLT mainly implements control, management, ranging, etc. of ONU. ONU is a user-end device in an optical network. It is generally placed on the user-end and provides users with voice, data and multimedia services. The ONU mainly selectively receives the downlink data broadcasted by the OLT, and sends the buffered data in the upstream direction in the sending window allocated by the OLT. ODN is an FTTH optical cable network based on PON equipment, which mainly provides optical transmission channels between OLT and ONU.

Exemplarily, a PON based on time division multiplexing (TDM) (TDM-PON) adopts Point-to-multipoint multiple access protocol. In the upstream direction, different ONUs burst upstream data to the OLT in time-divided time slots assigned by themselves, and the OLT needs to receive and process a large optical dynamic range. This is because:

First, the passive optical splitter in ODN can be one optical splitter or multiple cascaded optical splitters. Therefore, different ONUs may be at different optical splitting levels, resulting in huge differences in optical path losses connecting ONUs and OLTs.

Second, ONUs of the same optical splitting level may have different transmission distances, and link losses will also vary.

Third, ONU transmit power has a certain range limit, and the difference in transmit power will eventually be superimposed on the link.

Currently, as OLT needs to process a large optical dynamic range, avalanche photodiode (APD) and TIA are generally used for burst reception automatic gain control, and a preamble of a certain length is added before the uplink data to make the uplink burst Data is received stably.

As users' demand for access rates increases, Combo PON technology emerged as the times require, that is, one PON interface supports multiple technologies, such as: supporting gigabit PON (gigabit PON, GPON), 10 gigabit PON (10 gigabit- capable PON, XGPON) and 10 gigabit-capable symmetric PON (XGSPON) rates, enabling independent transmission and reception of GPON, XGPON and It should be understood that Combo PON may support a mixture of two or more PON interface rates, which is not limited in this application.

Standard G.984.5 stipulates that for C+ level OLTs in Combo PON, such as GPON, XGPON and XGSPON, the dynamic range of received power is -12 to -32dBm, -10 to -30.5dBm and -8 to -29dBm respectively. In the case of OLT multi-channel reception, link channels with high optical reception power may cause strong interference to link channels with low optical reception power, leading to crosstalk on each channel and deterioration of reception sensitivity.

As an example, the following solutions are provided to solve the problem of large dynamic range of received light of XGSPON OLT.

Figure 1 is a schematic structural diagram of a traditional OLT. As shown in Figure 1, the OLT includes: an optical amplifier 110, a filter 120 for separating upstream wavelength channels, a power splitter 130, photoelectric receivers 140a and 140b for each wavelength channel, a comparator 150, and an electrical switch 160 .

In a possible implementation, the optical signal 1 that passes through the optical amplifier 110 and the filter 120 is divided into two optical signals (for example, optical signal 2) after passing through the power splitter 110 . Among them, the ratio of the two optical signals can be configured arbitrarily, but it needs to be ensured that the power of the optical signal 2 on each branch is lower than the damage threshold of the photoelectric receiver on the corresponding branch.

Illustratively, taking 90% and 10% as an example, 90% of the optical signal 2 is transmitted to the photoelectric receiver 140a and converted into an electrical signal 1, and 10% of the optical signal 2 is transmitted to the photoelectric receiver 140b and converted into is the electrical signal 2. The electrical signal 1 and the electrical signal 2 are then sequentially input into the comparator 150 for comparison with a predetermined threshold. Finally, the electrical switch 160 selects the largest electrical signal of the two electrical signals that is lower than the predetermined threshold for further processing. For example, assume that the predetermined threshold is a, and the currents of the electrical signal 1 and the electrical signal 2 are b and c respectively. If c<b<a, the electrical switch 160 finally selects the electrical signal 1 for processing.

It should be noted that the predetermined threshold is related to the overload optical power of the photoelectric receiver.

In this implementation, by selecting an appropriate splitting ratio of the optical splitter, damage to the receiver caused by high-power incident light caused by the optical amplifier can be avoided. However, the introduction of a splitter will introduce losses to all powers, resulting in a loss of OLT receiving sensitivity. In addition, at least one set of photoelectric receivers is required for each wavelength channel, which will increase the design and overhead costs of the overall device.

To sum up, the current technical solution cannot control the dynamic range of received optical power while reducing the index requirements for electrical devices, reducing introduced losses, and avoiding interference to business signals. Therefore, how to effectively dynamically attenuate the optical power received by the OLT is a technical problem that needs to be solved urgently.

In view of this, this application proposes an optical power control device and method that can realize dynamic attenuation of the optical power received by the OLT, thereby reducing the index requirements for burst TIA. The optical power control device disclosed in this application can also ensure that the adjustment time of the optical power is controlled at the level of 10 ns to avoid interference with service signals. At the same time, reduce the loss introduced, that is, introduce Minimize sensitivity as much as possible.

In order to facilitate understanding of the embodiments of the present application, the following points are explained.

In the various embodiments of this application, if there is no special explanation or logical conflict, the terms and/or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments are based on their inherent Logical relationships can be combined to form new embodiments.

In this application, "plurality" means two or more. "And/or" describes the relationship between associated objects, indicating that there can be three relationships. For example, A and/or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. Among them, A and B can be singular or plural. In the text description of this application, the character "/" generally indicates that the related objects are in an "or" relationship.

It can be understood that the “first”, “second” and various numerical numbers in the embodiments shown below are only for convenience of description and are not used to limit the scope of the embodiments of the present application. The sequence numbers of each process below do not mean the order of execution. The execution order of each process should be determined by its functions and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

In the embodiments of this application, descriptions such as "when...", "in the case of..." and "if" all mean that the device will perform corresponding processing under certain objective circumstances, and do not limit the time, and It does not require the device to perform judgment actions during implementation, nor does it mean that there are other restrictions.

The technical solution provided by this application will be described in detail below with reference to the accompanying drawings.

Figure 2 is a schematic structural diagram of the first OLT provided by the embodiment of the present application. As shown in Figure 2, the OLT includes: an optical power control device, a photodetector and a transimpedance amplifier. The optical power control device includes: a power detector, an electric driver and an adjustable optical attenuator.

The power detector is configured to generate a first electrical signal and a first optical signal based on the input optical signal, output the first electrical signal from the second port of the power detector, and output the first optical signal from the third port of the power detector. The electric driver is used to determine the attenuation value of the adjustable light attenuator according to the first electrical signal obtained from the electric driver, and the second port of the electric driver is connected to the first port of the adjustable light attenuator. The adjustable optical attenuator is configured to receive a first optical signal from a second port of the adjustable optical attenuator, generate a second optical signal based on the first optical signal and the attenuation value, and output the second light from a third port of the adjustable optical attenuator. Signal.

Among them, the power detector can be an optical power monitor (OPM) or include a photodetector and a spectrometer. FIG. 3 is a schematic structural diagram of two implementation forms of the power detector provided by the embodiment of the present application. As shown in (a) of Figure 3, the power detector is an optical power monitor. The optical power monitor itself can detect the current. Specifically, after the input optical signal is input into the optical power monitor, a part of the optical signal (for example, 10%) is absorbed for power detection, and a first electrical signal is generated. Another part of the optical signal (for example, 90%) continues to transmit along the optical path to generate a first optical signal. This implementation introduces a small amount of loss. As shown in (b) of Figure 3, the power detector includes a beam splitter and a photodetector. First, an optical splitter is used to split the input optical signal into two optical signals in proportion. For example, 2% and 98%. Among them, the 2% light signal enters the photodetector as a control signal for power detection to generate a first electrical signal. 98% of the optical signal continues to be transmitted, generating the first optical signal.

Specifically, the dynamic range of the received optical power of the C+ level OLT in Combo PON is approximately -8 to -32dBm. Taking the target setting of the received optical power range as -18 to -32.2dBm as an example, the technical solution of this application is refined respectively for the electric driver, and a digital circuit solution and an analog circuit solution are proposed.

For example, FIG. 4 is a schematic structural diagram of two implementations of the electric driver provided by the embodiment of the present application. In a digital circuit scheme, the electrical driver is a comparator. As shown in (a) of Figure 4 , the key point of this digital circuit solution is that the comparator pre-stores a first threshold, and the first threshold is used for comparison with the first electrical signal. Specifically, the first electrical signal generated by the power detector is transmitted to the comparator. The comparator is used to determine the value of the adjustable optical attenuator according to a comparison result between the first threshold value and the first electrical signal. The attenuation value is also used to determine whether to generate an electric drive signal based on the attenuation value.

Optionally, in a digital circuit scheme, the electric driver includes a comparator and an amplifier. The key point of this digital circuit solution is that the comparator pre-stores a first threshold, and the first threshold is used for comparison with the second electrical signal.

Specifically, the first electrical signal generated by the power detector is amplified by an amplifier to generate a second electrical signal, and the second electrical signal is input to the electric driver. The comparator is used to determine the attenuation value of the adjustable optical attenuator according to the comparison result of the first threshold value and the second electrical signal, and is also used to determine whether to generate an electric driving signal according to the attenuation value.

For example, the above-mentioned comparator can be a current comparator, a microcontroller unit (microcontroller unit, MCU) or a field programmable gate array (field programmable gate array, FPGA).

In the analog circuit scheme, the electric driver is an amplifier. As shown in Figure 4(b), the key point of this analog circuit solution is: after the input optical signal is amplified by the first electrical signal generated by the power detector, an electrical drive signal is generated, which acts on the adjustable optical attenuator. on, used to realize continuous adjustment of the power of the first optical signal.

It should be noted that the power of the electric drive signal and the input optical signal have a monotonically increasing relationship. Therefore, the attenuation of the first optical signal and the power of the input optical signal also have a monotonically increasing relationship. That is to say, a mode is formed in which the output optical power is strongly attenuated when the input optical power is large, and the output optical power is weakly attenuated or not attenuated when the input optical power is small, thereby achieving dynamic control of the power range of the input optical signal.

In the technical solution of this application, an adjustable optical attenuator refers to an optical attenuator that controls the attenuation value through an electrical signal. For example, the adjustable optical attenuator may be an MZI optical attenuator, a MEMS technology variable optical attenuator or a thin film optical attenuator.

In one possible implementation, the adjustable optical attenuator is set to no attenuation without driving.

It should be understood that no attenuation means that the attenuation value of the adjustable optical attenuator is zero, and the electric driver may not generate an electric drive signal, or may output an electric drive signal of a certain fixed value. For example, 0V or 5V.

It should be noted that the electric driving signal may be expressed in the form of a current signal or a voltage signal, which is not specifically limited in this application.

For example, when the power of the input optical signal is small, the first electrical signal output by the power detector is small, the electric driver does not generate an electric drive signal, or the electric drive signal output by the electric driver is 0V, and the dimmable light cannot be driven. Attenuator, at this time, the attenuation value of the adjustable optical attenuator is 0dB, so the first optical signal is kept not attenuated, that is, the power of the second optical signal and the first optical signal are the same. When the input optical signal is large, the first electrical signal output by the power detector is large, and the electric driver determines to generate and output an electric drive signal to drive the adjustable optical attenuator to attenuate the power of the first optical signal. At this time, The attenuation value of the dimming attenuator is 10 dB, that is, the power of the second optical signal decreases by 10 dB relative to the first optical signal.

For example, the electrical detector may be a photodiode (PD) or APD. A TIA can be a sudden TIA or a continuous TIA.

It should be noted that compared with burst TIA, continuous TIA design is easier and the cost is lower. The optical power control device disclosed in this application can meet scene requirements by using continuous TIA, reduce system costs, and achieve dynamic control of the dynamic range of received optical power.

In a possible implementation, the photodetector of the power detector is selected to be a device greater than 10 GHz, and the response speed is less than 0.1 ns. For the electric driver, choose a device with a response time of about 10ns. For ns-level optical attenuators, the electrically adjusted response time is generally at the sub-ns level, and the thermally adjusted response time using a special structure is at the 10ns level.

Therefore, the power adjustment time of the entire solution can be controlled on the order of 10ns, which can meet the needs of the scene.

To sum up, the optical power control device disclosed in this application can achieve strong attenuation when the input optical signal power is large, and weak attenuation or no attenuation when the input optical signal power is small, thereby effectively controlling the optical power dynamic range of the OLT and reducing the impact of bursts. The indicator requirements of transmitting TIA and the loss of optical receiving sensitivity are avoided to avoid interference with business signals.

Figure 5 is a schematic flowchart of an optical power control method 500 provided by an embodiment of the present application. Specifically, the method 500 may It can be used in the device shown in Figure 2. The method 500 is described with reference to FIG. 2 . As shown in Figure 5, the specific implementation steps include the following steps.

S510, receives the input optical signal.

Wherein, the input optical signal can be generated using a light source. Specifically, the light source may be a tunable continuous laser capable of continuously outputting lasers of different frequencies with stable power. Alternatively, the light source can also be a tunable pulse laser capable of outputting pulse lasers of different frequencies with stable power. This application does not specifically limit this.

Exemplarily, the first port of the power detector receives an input optical signal from the laser. The power of this input optical signal is -18dBm.

S520: Generate a first electrical signal and a first optical signal based on the input optical signal.

In a possible implementation, power detection is performed on the input optical signal to generate a first electrical signal and a first optical signal. For example, during the process of transmitting the input optical signal, the optical power monitor simultaneously detects the power of the input optical signal. For example, a small part (for example, 10%) of the input optical signal is absorbed by the optical power monitor and generates a first electrical signal, and the first electrical signal is output from the second port of the optical power monitor, and the remaining majority (for example, 90%) of the input optical signal is used as the first optical signal and is output from the third port of the optical power monitor.

Another possible implementation manner is to split the input optical signal to generate a third optical signal and a first optical signal, and perform power detection on the third optical signal to generate a first electrical signal. Exemplarily, receiving an input optical signal from a first port of the optical splitter, performing power detection on a third optical signal (for example, 10%) generated after splitting based on the input optical signal as a control signal to generate a first electrical signal, and The remaining majority of the input optical signal (for example, 90%) is output as the first optical signal from the third port of the optical splitter.

S530, obtain the attenuation value, which is obtained based on the first electrical signal.

It should be noted that the above-mentioned “attenuation value” may be zero or non-zero, and this application does not specifically limit this.

For example, when the attenuation value is not zero, the power of the output optical signal and the input optical signal are different. When the attenuation value is zero, the power of the output optical signal and the input optical signal are the same.

As an example and not a limitation, the method further includes: determining whether to generate an electric drive signal according to the attenuation value, the electric drive signal being used to perform power adjustment on the first optical signal.

For example, when the attenuation value is not zero, the electric driver generates an electric drive signal according to the attenuation value for adjusting the power of the first optical signal. When the attenuation value is zero, the electric driver does not generate an electric drive signal. In this implementation, the attenuation value is used to determine whether to generate or not generate an electric drive signal, thereby achieving power adjustment of the first optical signal and achieving the effect of effectively controlling the dynamic range of the received optical power.

In a possible implementation, when the first electrical signal is greater than the first threshold, the electrical driving signal is determined to be generated according to the attenuation value. Alternatively, when the first electrical signal is less than the first threshold, it is determined according to the attenuation value that the electrical drive signal is not generated or that the electrical drive signal is zero or a fixed value. The fixed value of the electric driving signal may be zero or a non-zero value, such as 5V. That is to say, when the attenuation value is zero, it can be determined that no electric driving signal is generated, or the output voltage of the electric driving signal is always 0V or 5V.

It should be understood that the output voltage value of the electric driving signal here is only an illustrative description, and this application does not specifically limit it.

For example, it is assumed that the first threshold current corresponding to the power of the input optical signal -18dBm is bμA, and the dynamic range of the input optical signal is -8~-32dBm. When the power of the input optical signal is greater than -18dBm, the current of the first electrical signal is greater than bμA, and the corresponding adjustable optical attenuator stably produces an attenuation value of 10dB, that is, an electric drive signal is generated. Then the power dynamic range of the input optical signal is - 8～-18dBm is limited to -18～-28dBm. When the power of the input optical signal is less than -18dBm, the current of the first electrical signal is less than bμA, and the corresponding adjustable optical attenuator does not produce an attenuation value, or steadily produces an attenuation value of 0dB, that is, no electrical drive signal is generated, then the input optical signal will The power dynamic range of the signal is limited to -18~-32dBm, and finally the dynamic range of the input optical signal is limited from -8~-32dBm to -18~-32dBm to achieve dynamic attenuation of the received optical power.

In another possible implementation, the first electrical signal is amplified to generate a second electrical signal. When the second electrical signal is greater than the first threshold, the electrical driving signal is determined to be generated according to the attenuation value. Alternatively, when the second electrical signal is less than the first threshold, it is determined according to the attenuation value that the electrical drive signal is not generated or that the electrical drive signal is zero or a fixed value.

Wherein, the fixed value of the electric driving signal may be zero or non-zero value, such as 2 μA. That is to say, when the attenuation value is zero, it can be determined that no electric driving signal is generated, or the output current of the electric driving signal is always 0 μA or 2 μA.

It should be understood that the output current value of the electric driving signal here is only an exemplary description, and this application does not specifically limit it.

For example, it is assumed that the first threshold current corresponding to the power of the input optical signal -18dBm is bμA, and the dynamic range of the input optical signal is -8~-32dBm. When the power of the input optical signal is greater than -18dBm, the first electrical signal is amplified, and the current of the generated second electrical signal is greater than bμA. The corresponding adjustable optical attenuator stably produces an attenuation value of 10dB, that is, an electric drive signal is generated. Then limit the power dynamic range of the input optical signal to -8~-18dBm to -18~-28dBm; when the power of the input optical signal is less than -18dBm, the first electrical signal is amplified, and the current of the generated second electrical signal is less than bμA , the corresponding adjustable optical attenuator does not produce an attenuation value, or stably produces an attenuation value of 0dB, that is, it does not generate an electrical drive signal, then the power dynamic range of the input optical signal is still limited to -18~-32dBm, Finally, the dynamic range of the input optical signal is limited from -8~-32dBm to -18~-32dBm to achieve dynamic attenuation of the received optical power.

As an example and not a limitation, the method further includes amplifying the first electrical signal to generate an electrical driving signal.

It should be noted that in this implementation, the power of the electric drive signal and the input optical signal are in a monotonically increasing relationship, and the corresponding attenuation value of the input optical signal and the power of the input optical signal are also in a monotonically increasing relationship, thus forming an input light The mode of strong attenuation when the signal is large and weak attenuation when the input optical signal is small realizes dynamic control of the power range of the input optical signal.

In this implementation, the first electrical signal is amplified based on the analog circuit method to generate an electrical drive signal, which can realize continuous adjustment of the power of the input optical signal.

S540: Generate a second optical signal according to the attenuation value and the first optical signal.

In a possible implementation, the electric driving signal is generated according to the attenuation value, and the power of the first optical signal is adjusted according to the electric driving signal to generate the second optical signal. In this implementation, the attenuation value is used to control the output of the electric drive signal, and then adjust the power of the first optical signal to achieve the effect of dynamic attenuation of the received optical power.

S550, output the second optical signal.

To sum up, in the technical solution of this application, through the self-feedback adjustment of the power of the input optical signal, the optical power range of the OLT can be effectively controlled, reducing the index requirements for burst TIA and the loss of optical reception sensitivity, and avoiding the impact on the business. The signal causes interference.

Figure 6 is a schematic structural diagram of a second OLT provided by an embodiment of the present application. As shown in Figure 6, the OLT includes: optical power control device, photodetector #1 and TIA. The optical power control device includes: optical splitter, photodetector #2, logarithmic amplifier and MZIn ns level optical attenuator. Specifically, photodetector #1 is APD, and photodetector #2 is PD.

For example, assuming that the splitting ratio of the optical splitter is a, and a is the splitting coefficient of the PD branch, then the splitting coefficient of the MZI ns-level optical attenuator branch is 1-a. For example, a=2%, then after the input optical signal passes through the optical splitter, 2% of the input optical signal (i.e., an example of the third optical signal) is input to the PD as a control signal, and 98% of the input optical signal (i.e., the first optical signal) The signal (an example) continues to be transmitted along the optical path to the MZIn ns level optical attenuator.

At this time, the current I _pd generated by PD is:
I _pd =P _in *a*R (1)

Among them, P _in is the power of the input optical signal, and R is the responsivity of the PD, in A/W.

Further, after the current output by the PD (that is, an example of the first electrical signal) is amplified by a logarithmic amplifier, the drive current I _drv of the generated electrical drive signal is:

Among them, I _bias is the reference value of the logarithmic amplifier.

Assuming that the MZI ns-level optical attenuator adopts thermal adjustment, the power of the output optical signal (ie, an example of the second optical signal) is:
P _out ＝P _in *(1-a)*0.5*(1+cos(π*I _drv ² /I _π ² )) (3)

Among them, P _out is the power of the output optical signal of the MZI ns-level optical attenuator, that is, the optical power received by the APD, and I _π is the driving current corresponding to the maximum attenuation value of the MZI ns-level optical attenuator.

Specifically, after incorporating the above formula (1) and formula (2) into formula (3), the corresponding relationship between the power P _in of the input optical signal and the power P _out of the output optical signal can be obtained, that is:

FIG. 7 is a schematic diagram of the corresponding relationship between the power P _out of the first output optical signal and the power P _in of the input optical signal provided by the embodiment of the present application. Assuming a = 0.02, R = 1A/W, I _bias = 3μA, I _π = 7.2mA, simulate according to formula (4), and the simulation results shown in Figure 7 can be obtained.

(a) of Figure 7 shows how the optical power received by the APD (ie, the power of the output optical signal) changes under different input optical signal powers. Among them, the abscissa is the power P _in of the input optical signal, and the ordinate is the power P _out of the output optical signal, and the unit is dBm. Specifically, when the power range of the input optical signal is approximately -32 to -8dBm, the optical power range received by the APD is approximately -32.1 to -18.72dBm. This solution can achieve dynamic attenuation of the input optical power and achieve the set target value. Among them, the additional loss introduced is about 0.1dB.

(b) of Figure 7 shows the change of the optical power ratio output by the MZI adjustable optical attenuator under different input optical signal powers. Among them, the abscissa is the power P _in of the input optical signal in dBm, and the ordinate is the output optical power ratio P _mz of the MZI adjustable optical attenuator. Specifically, when the power range of the input optical signal is approximately -32 to -8dBm, the MZI adjustable optical attenuator output optical power ratio range is approximately 1 to 0. When the power of the input optical signal is about -32dBm, the MZI adjustable optical attenuator produces almost no attenuation. As the power of the input optical signal continues to increase, the proportion of the output optical power of the MZI adjustable optical attenuator gradually decreases, thereby realizing strong attenuation when the power of the input optical signal is large, and weak attenuation or no attenuation when the power of the input optical signal is small. Dynamic control.

In this implementation, the dynamic range of optical power received by photodetector #1 (eg, APD) can be effectively controlled through self-feedback of the input optical signal power. The optical power control device disclosed in this application can also reduce the index requirements of the OLT uplink burst TIA and reduce the electrical crosstalk between each channel of the OLT.

Figure 8 is a schematic structural diagram of a third OLT provided by an embodiment of the present application. As shown in Figure 8, the OLT includes: PD, MZI ns-level optical attenuator, electrical logarithmic amplifier, APD and TIA and other devices. It should be noted that the difference between this device and the device described in Figure 6 is that the MZI ns-level optical attenuator used in this device can replace the two components of the optical splitter and the MZI ns-level optical attenuator in Figure 6. That is to say, in this implementation, one optical splitter can be reduced in the link, which can further reduce the Low link loss.

For example, assume that the initial state of the MZI ns-level optical attenuator is set to: when no driving is applied, the output port P1 outputs 98% of the power of the input optical signal, and the output port P2 outputs 2% of the power of the input optical signal, that is, the input The optical signal does not attenuate, and the power of the input optical signal and the output optical signal are the same. Equivalent to the fact that there is a driving current I ₀ on the MZI optical attenuator when there is no driving.

At this time, the power of the output optical signal (that is, an example of the second optical signal) of the MZI ns-level optical attenuator is:
P _out ＝P _in *0.5*(1+cos(π*(I _drv -I ₀ ) ² /I _π ² )) (5)

Specifically, after incorporating the above formula (1) and formula (2) into formula (5), the corresponding relationship between the power P _in of the input optical signal and the power P _out of the output optical signal can be obtained, that is:

FIG. 9 is a schematic diagram of the corresponding relationship between the power P _out of the second output optical signal and the power P _in of the input optical signal provided by the embodiment of the present application. Assuming R=1A/W, I _bias =1μA, I _π =6.9mA, I ₀ =1.4mA, simulate according to formula (6), and the simulation results shown in Figure 9 can be obtained.

(a) of Figure 9 shows how the optical power received by the APD (ie, the power of the output optical signal) changes under different input optical signal powers. Among them, the abscissa is the power P _in of the input optical signal, and the ordinate is the power P _out of the output optical signal, and the unit is dBm. Specifically, when the power range of the input optical signal is approximately -32 to -8dBm, the optical power range received by the APD is -32 to -18.35dBm. This solution can effectively achieve dynamic attenuation of input optical power and achieve the set target value. Compared with the device shown in FIG. 6 above, since there is one less optical splitter with a fixed splitting ratio, the optical power control device theoretically does not introduce additional losses.

Figure 9(b) shows the change of the optical power ratio output by the MZI adjustable optical attenuator under different input optical signal powers. Among them, the abscissa is the power P _in of the input optical signal in dBm; the ordinate is the output optical power ratio P _mz of the MZI adjustable optical attenuator. Specifically, when the power range of the input optical signal is approximately -32 to -8dBm, the MZI adjustable optical attenuator output optical power ratio range is approximately 1 to 0. When the power of the input optical signal is below -30dBm, the MZI adjustable optical attenuator produces almost no attenuation. As the power of the input optical signal continues to increase, the proportion of optical power output by the MZI adjustable optical attenuator gradually decreases, thereby achieving strong attenuation for large input optical signal powers, and weak attenuation or no attenuation for small input optical signal powers. dynamic control.

In this implementation, the optical power range received by the APD can be effectively controlled through self-feedback of the input optical signal power. The optical power control device disclosed in this application can also reduce the index requirements for the OLT uplink burst TIA and reduce the electrical crosstalk between each channel of the OLT.

It should be noted that the optical power control device provided above is only an illustrative description and should not constitute any limitation on the technical solution of the present application.

It should be understood that the optical power control device mainly includes a power detector, an electric driver and an adjustable optical attenuator. Among them, there are two implementations of power detectors (for example, optical power monitor; optical splitter and photodetector), two implementations of electric drivers (for example, digital circuit scheme; analog circuit scheme) and adjustable optical attenuator (For example, MZIn ns level optical attenuator) can be used in any combination, and this application does not specifically limit this. For details, please refer to the implementation methods of Figure 6 and Figure 8 mentioned above. For the sake of simplicity, details will not be described here.

Figure 10 is a schematic structural diagram of a fourth OLT provided by an embodiment of the present application. As shown in Figure 10, OLT 1000 includes: optical power control device, photodetector, transimpedance amplifier and limiting amplifier (limiting amplifier, LA).

Specifically, after the input optical signal passes through the optical power control device, the optical signal #1 is output. For specific implementation, please refer to the above method 500. For the sake of brevity, no further details will be given here. The photoelectric detector is connected to the optical power control device and is used to monitor the optical signal Signal #1 undergoes photoelectric conversion to generate electrical signal #1. The transimpedance amplifier is connected to the photodetector and is used to amplify the electrical signal #1 to generate the electrical signal #2. The limiting amplifier is connected to the transimpedance amplifier and is used to amplify the electrical signal #2 to a saturated state and output the electrical signal #3.

It should be noted that the above schematic structural diagram of the OLT is only an illustrative description. The OLT may also include components such as filters, decision makers, decoders, and decoders, which are not specifically limited in this application.

FIG. 11 is a schematic diagram of a passive optical network system provided by an embodiment of the present application. As shown in Figure 11, the passive optical network system 2000 includes: multiple ONUs (eg, ONU#1, ONU#2...ONU#n), ODN and OLT. The ONU is used to send input optical signals to the ODN. ODN is used to transmit the input optical signal received from the ONU to the OLT. OL is used to receive input optical signals.

It should be noted that this application does not specifically limit the number of ONUs, ODNs and OLTs.

Those skilled in the art will understand that embodiments of the present application may be provided as methods, devices, and systems. The present application is described with reference to flowcharts and/or block diagrams of methods, apparatuses and systems according to embodiments of the present application. Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the scope of the embodiments of the present application. In this way, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of this application and equivalent technologies, then this application is also intended to include these modifications and variations.

It should be understood that the specific examples in the embodiments of this application are only to help those skilled in the art better understand the technical solutions of this application. The above-mentioned specific implementations can be considered as the optimal implementations of this application, but do not limit the implementation of this application. range of examples.

Those of ordinary skill in the art will appreciate that the algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each specific application, and such implementations should not be considered beyond the scope of this application.

In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the coupling or direct coupling or communication connection between each other shown or discussed may be through some interfaces, and the indirect coupling or communication connection of the devices or units may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or they may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, each unit can exist physically alone, or two or more units can be integrated into one unit.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application. should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

An optical power control device, characterized by comprising: a power detector, an electric driver and an adjustable optical attenuator, wherein:

The power detector is configured to generate a first electrical signal and a first optical signal according to the optical signal received by the first port of the power detector, and is also configured to output the first electrical signal and the first optical signal from the second port of the power detector. a first electrical signal, and outputting the first optical signal from a third port of the power detector;

The electric driver is used to determine the attenuation value of the adjustable optical attenuator according to the first electrical signal input from the first port of the electric driver, and the second port of the electric driver is connected to the adjustable The first port connection of the optical attenuator;

The adjustable optical attenuator is configured to receive the first optical signal from the power detector from the second port of the adjustable optical attenuator, and based on the first optical signal and the attenuation value A second optical signal is generated and further used to output the second optical signal from a third port of the adjustable optical attenuator.
The device according to claim 1, wherein the power detector is an optical power monitor.
The device according to claim 1, wherein the power detector includes: a beam splitter and a photodetector, wherein:

The optical splitter is configured to receive the input optical signal from a first port of the optical splitter and generate the first optical signal and a third optical signal based on the input optical signal, from a third optical signal of the optical splitter. Two ports output the third optical signal, and the third port of the optical splitter outputs the first optical signal;

The photodetector is configured to receive the third optical signal from the optical splitter from the first port of the photodetector, generate the first electrical signal based on the third optical signal, and generate the first electrical signal from the first port of the photodetector. The second port of the photodetector outputs the first electrical signal.
The device according to any one of claims 1 to 3, characterized in that the electric driver is a comparator, wherein:

The comparator pre-stores a first threshold, and the first threshold is used for comparison with the first electrical signal,

The comparator is configured to determine an attenuation value of the adjustable light attenuator based on a comparison result between the first threshold and the first electrical signal, and is further configured to determine whether to generate an electric drive signal based on the attenuation value.
The device according to any one of claims 1 to 3, characterized in that the electric driver includes: an amplifier and a comparator, wherein:

The first port of the amplifier is connected to the second port of the power detector, and is used to amplify the first electrical signal to generate a second electrical signal;

The first port of the comparator is connected to the second port of the amplifier, the second port of the comparator is connected to the first port of the adjustable optical attenuator, and the comparator pre-stores a first threshold, so The first threshold is used for comparison with the second electrical signal,

The comparator is used to determine the attenuation value of the adjustable light attenuator according to the comparison result of the first threshold and the second electrical signal, and is also used to determine whether to generate the electric drive according to the attenuation value. Signal.
The device according to any one of claims 1 to 3, characterized in that the electric driver is an amplifier, wherein:

The amplifier is used to amplify the first electrical signal, determine the attenuation value of the adjustable optical attenuator based on the amplified electrical signal, and is also used to generate the electric drive signal according to the attenuation value.
The device according to any one of claims 1 to 6, characterized in that the adjustable optical attenuator is a Mach-increasing Del interferometer MZI optical attenuator, microelectromechanical system MEMS technology variable optical attenuator or thin film optical attenuator.
An optical power control method, characterized by including:

Receive input optical signal;

generating a first electrical signal and a first optical signal based on the input optical signal;

Obtain an attenuation value, the attenuation value is obtained based on the first electrical signal;

Generate a second optical signal based on the attenuation value and the first optical signal;

Output the second optical signal.
The method of claim 8, further comprising:

Whether to generate an electric drive signal is determined according to the attenuation value, and the electric drive signal is used to perform power adjustment on the first optical signal.
The method according to claim 8 or 9, characterized in that generating a first electrical signal based on the input optical signal includes:

Power detection is performed on the input optical signal to generate the first electrical signal.
The method according to claim 8 or 9, characterized in that generating the first electrical signal and the first optical signal based on the input optical signal includes:

Spectroscopically split the input optical signal to generate a third optical signal and the first optical signal;

The third optical signal is power detected to generate the first electrical signal.
The method of claim 9, wherein determining whether to generate an electric drive signal based on the attenuation value includes:

When the first electrical signal is greater than a first threshold, it is determined to generate the electrical drive signal according to the attenuation value; or,

When the first electrical signal is less than a first threshold, it is determined according to the attenuation value that the electrical drive signal is not generated or that the electrical drive signal is a fixed value.
The method of claim 9, wherein determining whether to generate an electric drive signal based on the attenuation value includes:

Amplify the first electrical signal to generate a second electrical signal;

When the second electrical signal is greater than the first threshold, it is determined to generate the electrical drive signal according to the attenuation value; or,

When the second electrical signal is less than the first threshold, it is determined according to the attenuation value that the electrical drive signal is not generated or that the electrical drive signal is a fixed value.
The method of claim 9, further comprising:

The first electrical signal is amplified to generate the electrical drive signal.
The method according to any one of claims 9 to 14, characterized in that generating a second optical signal according to the attenuation value and the first optical signal includes:

Determine and generate the electric drive signal according to the attenuation value;

The power of the first optical signal is adjusted according to the electrical drive signal to generate the second optical signal.
An optical line terminal OLT, characterized in that it includes: a photodetector, a transimpedance amplifier TIA, and an optical power control device according to any one of claims 1 to 7, wherein:

The photodetector is connected to the third port of the adjustable light attenuator for photoelectric conversion of the second optical signal to generate a third electrical signal;

The TIA is connected to the photodetector and used to amplify the third electrical signal to generate an output electrical signal.
A passive optical network system, characterized by including: optical network unit ONU, optical distribution network ODN and And the OLT as claimed in claim 16, wherein:

The ONU is used to send input optical signals to the ODN;

The ODN is used to transmit the input optical signal received from the ONU to the OLT;

The OLT is used to receive the input optical signal.