WO2009012699A1

WO2009012699A1 - An apparatus and a method for amplifying optical signals in a passive optical network and an optical line terminal

Info

Publication number: WO2009012699A1
Application number: PCT/CN2008/071674
Authority: WO
Inventors: Limin Dong; Chan Zhao
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-07-20
Filing date: 2008-07-17
Publication date: 2009-01-29
Also published as: CN101350670A; CN101350670B

Abstract

An apparatus and a method for remote amplification in a passive optical network and an optical line terminal are provided in this invention, with regard to optical communication field, and comprise: generating a control message to control the amplification of upstream optical signals according to the delay of optical signals from optical network units to the upstream optical signal amplifier and different arrival time of upstream optical signals from optical network units to the upstream optical signal amplifier; transmitting the downstream optical signal composed of a downstream service signal and the said control message; receiving the said downstream optical signal, extracting the said control message and generating a pump current to control the said upstream optical signal amplifier according to the said control message; amplifying upstream optical signals arriving at different time according to the said pump current. Monitoring and managing remote amplification in a PON as well as dynamically adjusting the gain of the said upstream burst signals for equalization are realized in this invention. The scheme of this invention enjoys a lower cost compared to the existent gain stabilization technique of amplifiers.

Description

Amplifying device and method for optical signal in passive optical network and optical line terminal

The present invention relates to the field of optical communications, and more particularly to an amplifying apparatus and method for optical signals in a passive optical network and an optical line termination.

Background technique

With the rise of emerging services such as video on demand, high definition television, and online games, users are increasingly demanding bandwidth, and the development of fiber-to-the-home can effectively guarantee the bandwidth of the "last mile" access network. The PON (Passive Optical Network) technology eliminates the active nodes in the traditional access network and helps reduce the maintenance cost of operators. It is one of the most widely used fiber-to-the-home technologies. The existing PON system includes BPON (Broadband Passive Optical Network) and GPON (Gigabit Passive Optical Network) developed by the full service access network organization; and IEEE (Institution of Electrical) And Electronics Engineers, Institute of Electrical and Electronics Engineers, EPON (Ethernet Passive Optical Network). At present, the coverage of ΡΟΝ is 20km, and the downlink and uplink rates are on the order of gigabit.

The PON of various systems has basically the same network architecture. As shown in Figure 1, the OLT (Optical Line Terminal) is located in the central office, and the Optical Network Unit (ONU) is located in the user's home (or roadside, building, etc.). The OLT and the ONU are passive. The ODN (Optical Distribution Network) is connected. The OLT and the passive optical splitter are connected by a trunk fiber, and the optical splitter realizes point-to-multipoint optical power distribution and is connected to multiple ONUs through multiple branch fibers. The direction from the OLT to the ONU is called the downlink direction, and the direction from the ONU to the OLT is called the uplink direction.

The point-to-multipoint tree topology of PON determines that each ONU must communicate with the OLT in a shared medium. The downlink signal of the OLT is sent to all ONUs through TDM (Time Division Multiplexing) broadcast, and uses specific identifiers, such as virtual channels for BPON. The identifier, the EPON logical link identifier, the GPON virtual channel identifier, and the allocation identifier indicate which ONU each time slot belongs to. The optical signal power of all the information of all ONUs is divided into several parts at the optical splitter to reach each ONU via each branch fiber. Each ONU collects its own data according to the corresponding identifier, and the data of other time slots are discarded. The uplink direction of the ONU is accessed by time division multiple access. Under the control of the OLT, each ONU transmits its own uplink signal only in the time slot designated by the OLT, and the time slots of the ONUs meet at the optical splitter. The PON system ensures that the uplink signals of the ONUs do not collide through the ranging and multiple access control. Since each ONU reaches the optical splitter along different branch fibers, the distances of different branch fibers are different. For example, the maximum distance difference between the ONUs of GPON is 20 km. Therefore, the attenuation of the optical power is different, and the optical power of the ONU optical transmitter is also inconsistent. The optical power of the uplink signals of different ONUs reaches the optical splitter by up to 10 dB, and is rapidly changing (near two The protection interval between the uplink signals of the ONUs is only 25 ns), which is called the burst uplink signal.

The rise of next-generation optical access networks raises the need for PONs to be extended, so that optical transmission achieves a system target of 10 Gbps symmetric rate, 100 km transmission distance, and 512 split ratio. The remoteness of the PON is conducive to the integration of the access network and the metropolitan area network, reducing the number of network nodes, and further reducing maintenance costs.

In order to achieve the PON's remoteness, it has been proposed to add an optical amplifier to the remote node of the PON to improve the power budget. Referring to FIG. 2, the OLT adds a wavelength division multiplexer WDM to the backbone fiber at the remote node optical splitter for separating the uplink signal with a wavelength of 1310 nm and the downlink signal with a wavelength of 1490 nm, and one for each of the uplink and downlink signals. The EDFA (erbium doped fiber amplifier) is separately amplified. From the perspective of improving the power budget, the OLT of the architecture can be located at the core network node, and the distance from the ONU reaches 100 km.

The advantage of using an optical amplifier is that the delay to the signal is small. The downlink signal of the PON is in continuous mode, and it is more suitable to use EDFA amplification. However, the problem with this technology is that the uplink signal of the PON is in burst mode, and the transmitted optical powers of different ONUs are different, and the branch fibers of different distances reach the optical splitter, and experience different link attenuation. Therefore, the uplink signals of different ONUs are The optical power of the splitter is different, the difference is up to 10dB, and the guard interval between the uplink signals of two adjacent ONUs is only 25ns. The typical transient effect response time constant of an EDFA is on the order of microseconds. The sudden rise of the uplink signal after the EDFA is amplified will cause a surge, resulting in signal distortion.

In order to overcome the transient effect of EDFA and make the EDFA suitable for amplifying the burst uplink signal, it has been proposed to introduce an amplifier gain clamp technique. Referring to FIG. 3, the upstream signal of the wavelength λ _来自 from the ONU arrives before the EDFA located at the remote node, and firstly passes a small part of the optical power input optical receiver through a coupler, and the controller determines a light according to the received optical power. The compensation value drives a laser with a wavelength of λ _ε , and λ _ε and λ _ΡΟΝ are two different wavelengths. The signal light of λ _ΡΟΝ is input to the EDFA together with the control light of λ _ε for amplification, and λ _{e is} filtered out at the output end of the EDFA, and the amplified λ _ΡΟΝ signal light is transmitted to the OLT. The principle of gain clamping is that the signal light of λ _ΡΟΝ and the control light of λ _ε share the gain of the EDFA, while the pump power of the EDFA remains unchanged, so the EDFA is λ _ΡΟΝ the signal light and λ. The amount of gain provided by the control light remains the same. The optical receiver (PD) detects the signal light power of λ _,, and dynamically changes the magnitude of the control light power of λ c emitted by the laser (LD ) through the controller, so that both the signal light and the control light are input to the optical power of the EDFA. And keep constant, so the gain of the λ _ΡΟΝ signal light is kept constant, thus eliminating the surge caused by the EDFA transient effect.

A problem with the above techniques is that the use of gain-clamped amplifiers introduces additional cost increases, requires the addition of lasers, receivers, and the addition of optical filters at the output of the EDFA. In addition, a series of processing procedures such as uplink optical power reception, decision, and adjustment of the laser output power need to be completed in the instant when the uplink optical power arrives, which is technically difficult.

Summary of the invention

The embodiment of the invention provides an amplifying device, an amplifying method and an optical line terminal for an optical signal in a PON, so as to solve the amplification problem of the uplink burst signal, that is, dynamically adjusting the upstream optical signal amplifier by using the control information in the downlink optical signal. The pump current is sized to achieve equalized gain of the upstream burst optical signals of different powers. The technical solutions are as follows:

In order to solve the above technical problem, an embodiment of the present invention provides an optical line terminal, where the light Road terminals include:

a ranging unit, configured to measure a delay of the optical signals of the plurality of optical network units to the upstream optical signal amplifier, and calculate, according to the delay, different time times when the optical signals sent by the multiple optical network units reach the upstream optical signal amplifier;

a control information generating unit, configured to generate control information for controlling amplification of the uplink optical signal according to the ranging result; the control information includes a list of amplification gain values corresponding to the different times;

a combiner, configured to synthesize a service signal and the control information into an electrical signal;

The optical transceiver module is configured to convert the electrical signal into an optical signal as a downlink optical signal output. An embodiment of the present invention further provides an amplifying device for an optical signal in a passive optical network, where the amplifying device includes:

a control information extracting unit, configured to receive a downlink optical signal from the optical line terminal, and extract control information from the downlink optical signal;

a pumping unit, configured to generate a pump current of the upstream optical signal amplifier according to the control information; an upstream optical signal amplifier, configured to receive the pump current, and amplify the uplink optical signal according to the pump current.

An embodiment of the present invention further provides an amplifying method for a passive optical network, where the method includes: obtaining, according to a delay of an optical signal of each optical network unit to an upstream optical signal amplifier, and an uplink optical signal sent by each optical network unit. Generating control information for controlling amplification of the upstream optical signal at different times of the upstream optical signal amplifier;

Combining the downlink service signal and the control information into a downlink optical signal output;

Receiving the downlink optical signal and extracting the control information, and generating, according to the control information, a pump current for controlling the upstream optical signal amplifier;

The upstream optical signals arriving at different times are amplified according to the pump current.

The above embodiments of the present invention are applicable to the remote amplification problem of the passive optical network, and can effectively solve the amplification problem of the uplink burst signal. Through the gain control of the upstream optical signal amplifier, the problem that the upstream burst signal generates a surge phenomenon after passing the upstream optical signal amplifier is solved, and finally the balance is increased. The remote amplifier can be monitored and managed by the control information including the uplink time information of the upstream optical signals of the optical network units. Compared with the existing amplifier gain clamping technology, the technical solution of the embodiment of the invention is reduced in cost.

DRAWINGS

1 is a structural diagram of a PON system in the prior art;

2 is a schematic diagram of implementation of using an optical amplifier in a PON in the prior art;

3 is a schematic diagram of an amplifier gain clamping technique used in the prior art 2;

4 is a schematic structural diagram of an optical line terminal according to Embodiment 1 of the present invention;

6 is a schematic structural diagram of a system for amplifying an optical signal in a PON according to Embodiment 3 of the present invention; FIG. 7 is a flowchart of a method for amplifying an optical signal in a PON according to Embodiment 4 of the present invention; A flow chart of measuring the distance of the remote amplifier to the optical line terminal OLT provided in Embodiment 4;

Figure 9 is a flow chart showing the generation of pump current for controlling an upstream optical signal amplifier based on control information according to Embodiment 4 of the present invention.

detailed description

The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

Embodiments of the present invention provide an amplifying device, an amplifying method, and an optical line terminal for an optical signal in a PON, and dynamically adjusting a pumping current of an upstream optical signal amplifier by using control information in a downlink optical signal to implement different power uplinks. The purpose of the equalization gain of the signal.

Example 1

Referring to FIG. 4, Embodiment 1 of the present invention provides an optical line terminal, where the optical line terminal includes: a ranging unit 101, which is connected to the control information generating unit 102, the combiner 103, and the optical transceiver module 104, and is used for measurement. a delay of the optical signals from the plurality of optical network units to the upstream optical signal amplifier, and calculating, according to the delay, the different times when the optical signals sent by the plurality of optical network units reach the upstream optical signal amplifier Engraved

The ranging unit 101 performs ranging at the initial time, including measuring the delay of the optical signals of all the ONUs to the OLT and the delay of the optical signals of the upstream optical signal amplifiers to the OLT, thereby calculating the optical signals of the respective ONUs to the upstream optical signal amplifiers. Delay.

At the same time, the ranging unit 101 allocates an uplink time slot to all the ONUs according to the dynamic bandwidth allocation algorithm, and writes the uplink time slot allocation result of all the ONUs into the downlink frame to notify each ONU of the time slot of the uplink optical signal, and The ranging result obtained by copying one ranging and the uplink time slot allocation result are output to the control information generating unit 102.

Therefore, according to the delay time of the uplink time slot and the optical signal of each optical network unit to the upstream optical signal amplifier, different timings of the uplink optical signals sent by the optical network units to the upstream optical signal amplifier are calculated.

The control information generating unit 102 is connected to the ranging unit 101, the optical transceiver module 104, and the combiner 103, and configured to generate control information for controlling amplification of the uplink optical signal according to the ranging result;

The control information is generated according to the delay of the optical signal of each ONU to the upstream optical signal amplifier and the different time when the uplink optical signal sent by each optical network unit reaches the upstream optical signal amplifier. The control information includes a list of amplification gain values corresponding to the different times. The amplification gain value corresponds to a timing at which the uplink optical signal reaches the upstream optical signal amplifier, and the delay of the optical signal corresponding to the uplink optical signal to the upstream optical signal amplifier is larger, the greater the gain value is. The smaller the delay, the smaller the gain value. For example, if the distance of ONU1 is far, and the uplink signal of ONU1 reaches the upstream optical signal amplifier at the ith time, the amplification gain value is a larger value at the i-th time. On the other hand, if the distance of the ONU2 is relatively close and the uplink signal of the ONU2 reaches the upstream optical signal amplifier at the jth time, the amplification gain value is a small value at the jth time. It is worth noting that since the OLT knows in advance the uplink time slots of all ONUs, the control information is not sent until the i or jth time, but is sent out in advance enough time.

a combiner 103, connected to the control information generating unit 102 and the ranging unit 101, for synthesizing the service signal and the control information into an electrical signal; In the actual optical signal transmission process, in the downlink direction, the combiner 103 converts the control information, for example, performing time division multiplexing to generate an electrical signal for outputting to the ranging unit; and in the uplink direction, the combiner 103 is for ranging. The signal output by the unit passes directly without any processing;

The optical transceiver module 104 is connected to the ranging unit 101 and the control information generating unit 102, and is configured to convert the electrical signal into an optical signal for output as a downlink optical signal.

In the actual service transmission, the power information extraction module in the optical transceiver module 104 can also extract the uplink optical signal, in order to achieve the equalization gain of the uplink optical signal, because the uplink power of the different ONUs is different. The power information is used to dynamically adjust control information for controlling the amplification of the upstream optical signal, thereby performing equalization gain on the uplink optical signal.

Therefore, the control information generating unit 102, in addition to generating the control information for controlling the amplification of the upstream optical signal according to the ranging result, initially, after the actual service transmission starts, the control information adjusting module in the control information generating unit 102 will also be The uplink direction receives the power information in the uplink optical signal output by the power information extraction module to dynamically adjust the control information.

Example 2:

Referring to FIG. 5, the embodiment 2 provides an amplifying device for an uplink optical signal in a PON, including:

The control information extracting unit 201 is connected to the pumping unit 202, receives the downlink optical signal from the optical line terminal, and extracts control information from the downlink optical signal to the pumping unit 202; the pumping unit 202, and the uplink The optical signal amplifier 203 is connected to receive the control information output by the control information extracting unit 201 to generate a pump current of the upstream optical signal amplifier 203;

The upstream optical signal amplifier 203 is connected to the pumping unit 202, receives the pump current generated by the pumping unit 202, and amplifies the upstream optical signal according to the pumping current.

The control information extracting unit 201 specifically includes:

The optical receiver 204 is connected to the control unit 205, receives the downlink optical signal from the optical line terminal, and converts the downlink optical signal into an electrical signal;

The control unit 205 is connected to the pump unit 202 and receives an electrical signal from the optical receiver 204. And extracting control information from the electrical signal.

The upstream optical signal is sent from the optical network unit ONU and is a burst mode signal. After being separated by WDM, it is input into the uplink optical amplifier.

Due to the difference in the transmitted optical power of different ONUs, and the branched optical fibers passing through different distances reach the optical splitter, different link attenuations are experienced. Therefore, the optical power of the uplink signals of different ONUs reaching the splitter is different. In order to achieve the equalization gain of the uplink optical signal, the power information of the uplink optical signal can be extracted to dynamically adjust the control information for controlling the amplification of the uplink optical signal, thereby performing equalization gain on the uplink optical signal. For example, after the upstream optical signal amplifier, the uplink signal output optical power of ONU1 and ONU2 is substantially flat to achieve effective amplification of the uplink burst signal of the PON.

Further, the upstream optical signal amplifier described in Embodiment 2 of the present invention may use an EDFA (Doped Fiber Catenary Amplifier), a TDFA (Ytterbium Doped Fiber Amplifier) or an SOA (Semiconductor Optical Amplifier). Embodiments of the invention do not limit the optical amplifiers used.

In addition, in the second embodiment, an amplifying device for an uplink optical signal in a PON is provided. The amplifying device can be separately used for amplifying an uplink optical signal, and can also be combined with a downstream optical signal amplifier to form an integrated amplifying device. The amplification of the upstream optical signal and the downstream optical signal, any embodiment that uses the spirit of the present invention and does not depart from the essence of the present invention is within the scope of the present invention.

Example 3:

Referring to FIG. 6, the present invention provides an amplifying system for optical signals in a PON in which an amplifying device and an optical line terminal are applied in the embodiment of the present invention, including:

The optical line terminal 301 is configured to generate control information to be output in the downlink optical signal, or extract power information in the uplink optical signal in an uplink direction to dynamically adjust the control information;

The remote amplifying device 302 is configured to receive the downlink optical signal, and extract the control information to amplify the uplink optical signal.

Therefore, in the down direction:

In the optical line terminal 301, the service signal becomes a data signal after being processed by mapping, multiplexing, framing, and the like. Number output. The control information generating unit issues control information, and the control information and the data signal input combiner perform time division multiplexing, and the multiplexed control signal and the data signal input ranging unit perform framing and the like, and perform electro-optical conversion through the optical transceiver module. 1490nm downstream optical signal, input into PON fiber;

Before entering the remote amplifying device 302, the WDM is separated using a wavelength division multiplexer.

In the remote amplifying device 302, the downstream optical signal (including the control information) from the OLT splits a small portion of the optical power and most of the optical power, and most of the optical power is amplified by the downstream optical signal amplifier, and a small portion of the optical power is input to the optical receiver. After being converted into an electrical signal, the control unit is input, and the control unit extracts the control information and generates a pump current adjustment amount to the pump unit, and the pump unit adjusts the pump current of the upstream optical signal amplifier according to the adjustment amount.

In the upward direction:

The 1310 nm upstream optical signal from one or more ONUs is separated using a wavelength division multiplexer WDM.

In the remote amplifying device 302, the upstream optical signal is amplified by the upstream optical signal amplifier and output from the PON optical fiber;

After the upstream optical signal passes through the wavelength division multiplexer WDM, it enters the optical line terminal 301.

In the optical line terminal 301, the signal amplified by the upstream optical signal amplifier is input to the optical transceiver module for photoelectric conversion into an electrical signal, and the optical transceiver module extracts power information input control information of the burst signal from a small portion of the electrical signal. The generating unit, the control information generating unit dynamically adjusts the control information according to the power information; the majority of the input ranging unit of the electrical signal performs processing such as deframing, and finally performs processing such as demultiplexing and demapping, and restores to a service signal.

Example 4:

Referring to FIG. 7, Embodiment 4 of the present invention provides a method for amplifying an optical signal in a PON, and the specific steps are as follows:

Step 101. According to the delay of the optical signal of each optical network unit to the upstream optical signal amplifier, and the uplink optical signal sent by each optical network unit calculated according to the delay, the uplink optical signal amplifier is obtained. At different times, generating control information for controlling amplification of the upstream optical signal;

After the network equipment connection is completed, the initial time ranging is performed, including measuring the delay of the optical signals of all the ONUs to the OLT and the delay of the optical signals of the upstream optical signal amplifiers to the OLT, thereby calculating each ONU to the upstream optical signal amplifier. The delay of the optical signal.

Wherein, the upstream optical signal amplifier is located in the remote amplifier device.

All the ONUs are allocated an uplink time slot according to the dynamic bandwidth allocation algorithm, and the uplink time slot allocation result of all the ONUs is written into the downlink frame, and each optical network unit is notified to issue a time slot of the uplink optical signal.

Therefore, according to the time slot of the optical signal sent by each optical network unit and the optical signal of each optical network unit to the upstream optical signal amplifier, different times when the uplink optical signal sent by each optical network unit reaches the uplink optical signal amplifier is calculated.

The control information is generated according to the delay of the optical signal of each ONU to the upstream optical signal amplifier and the different time that the upstream optical signal transmitted by each optical network unit reaches the upstream optical signal amplifier. The control information includes a list of amplification gain values corresponding to the different times. The amplification gain value corresponds to a timing at which the uplink optical signal reaches the upstream optical signal amplifier, and the delay of the optical signal corresponding to the uplink optical signal to the upstream optical signal amplifier is larger, the greater the gain value is. The smaller the delay, the smaller the gain value.

Step 102: Synthesize the downlink service signal and the control information into a downlink optical signal output. Step 103: Receive the downlink optical signal and extract the control information, and generate, according to the control information, a control for the uplink optical signal amplifier. Pump current

It is worth noting that since the OLT knows in advance the uplink time slots of all ONU upstream optical signals, the amplifier control signal is not sent until the i or jth time, but is sent out in advance enough time.

Therefore, the control information is extracted and stored in an internal memory before the upstream optical signal reaches the upstream optical signal amplifier.

Step 104: Amplify the upstream optical signals arriving at different times according to the pump current. The prior art only provides the ranging technology of the OLT to the ONU, which is completed by the ranging unit of the OLT, but the ranging of the remote amplifier is not available in the prior art. The embodiment of the present invention provides the technical solution according to the present invention. The OLT measures the distance measurement of the remote amplifier, as shown in FIG. 8. The step of measuring the delay of the optical signal from the remote amplifier to the optical line terminal OLT specifically includes:

Step a: The optical line terminal notifies an optical network unit to send uplink continuous light, and turns off all other optical network units;

Step b: The optical line terminal sends a downlink ranging grant signal, and records the initial time T1; Step c: The remote amplifier receives the downlink ranging grant signal and converts it into an electrical signal;

Step d: parsing the outgoing ranging grant signal, and suddenly changing the pumping current significantly, so that the continuous continuous light of the uplink generates a sudden rising edge or falling edge;

Step e, when the optical line terminal detects that the continuous continuous light of the uplink generates a sudden rising edge or a falling edge, the time T2 at this time is recorded;

Step f: Calculate the round-trip time of the remote amplifier to the optical line terminal is T2-T1, and obtain the delay of the optical signal as (Τ2-Τ1) /2, and calculate the distance from the remote amplifier to the optical line terminal by the round-trip time.

As shown in FIG. 9, in step 103, the step of receiving the downlink optical signal and extracting the control information, and generating a pump current for controlling the upstream optical signal amplifier according to the control information specifically includes:

Step 103a. Receive the downlink optical signal and convert the downlink optical signal into an electrical signal; Step 103b. Extract the control information from the electrical signal, and store the information in an internal memory;

Step 103c. Generate a pump current adjustment amount output according to the electrical signal;

Step 103d. Adjust the pump current of the upstream optical signal amplifier according to the pump current adjustment amount. For example, in the protection time before the upstream optical signal from the ONUi reaches the upstream optical signal amplifier at the i-th time, the control unit extracts the gain value of the control information at the ith time to generate a pump current. The adjustment amount is sent to the pump unit, and the pump unit increases the pump current so that the pump current of the upstream optical signal amplifier increases at the ith time; the upstream optical signal from the ONUj reaches the upstream optical signal at the jth time. During the protection time before the amplifier, the control unit extracts the gain value of the control information at the jth time, generates a pump current adjustment amount and sends it to the pump unit, and the pump unit reduces the pump current so that the upstream optical amplifier is at the jth The pump current at each moment is reduced.

In the actual service transmission, the optical power of the uplink signals of different ONUs arrives at different levels of the splitter. In order to achieve the equalization gain of the uplink optical signal, the power information of the uplink optical signal can be extracted to dynamically adjust the method control signal. , thereby equalizing the gain of the upstream optical signal.

The initial gain value is not dynamically adjusted, so using the initial gain value to amplify the upstream optical signal may not achieve the desired result. In the embodiment of the present invention, the power information of the uplink optical signal is used to dynamically adjust the amplifier control signal, and each of the uplink optical signals is repeatedly extracted. Since the control signal is also repeatedly extracted, the dynamic adjustment is repeated until stable. Working status: The upstream light of all ONUs is the same optical power after amplification.

Therefore, after the remote amplifier, the uplink signal output optical power of ONU1 and ONU2 is substantially flat, thereby realizing effective amplification of the uplink burst signal of the PON.

The above embodiments of the present invention are applicable to the remote amplification problem of the passive optical network, and can effectively solve the amplification problem of the uplink burst signal, and solve the gain control of the uplink optical signal amplifier to solve the problem that the uplink burst signal passes through the upstream optical signal amplifier. The problem of the surge phenomenon is finally realized, and the equalization gain is finally realized. The control information includes the uplink time information of the uplink optical signals of the network elements, and the remote amplifier can be monitored and managed. Compared with the existing amplifier gain clamping technology, the present invention is implemented. The technical solution costs are reduced.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., which are within the spirit and scope of the present invention, should be included in the protection of the present invention. Within the scope.

Claims

Claim

An optical line terminal, wherein the optical line terminal comprises:

The ranging unit (101) is configured to measure a delay of the optical signals of the plurality of optical network units to the upstream optical signal amplifier, and calculate, according to the delay, different time times when the optical signals sent by the multiple optical network units reach the upstream optical signal amplifier ;

a control information generating unit (102), configured to generate, according to the ranging result, control information for controlling amplification of the uplink optical signal; the control information includes a list of amplification gain values corresponding to the different time instants;

a combiner (103) for synthesizing the traffic signal and the control information into an electrical signal;

The optical transceiver module (104) is configured to convert the electrical signal into an optical signal as a downlink optical signal output.

The optical line terminal according to claim 1, wherein the optical line terminal further comprises: a power information extraction module, configured to extract power information of an uplink optical signal from the optical network unit, and use the power The information is output to the control information adjustment module;

And a control information adjustment module, configured to receive the power information, to adjust the control information used to control amplification of the uplink optical signal.

3. An amplifying device for an optical signal in a passive optical network, characterized in that the amplifying device comprises:

a control information extracting unit (201), configured to receive a downlink optical signal from the optical line terminal, and extract control information from the downlink optical signal;

a pumping unit (202), configured to generate a pumping current of the upstream optical signal amplifier according to the control information;

An upstream optical signal amplifier (203) is configured to receive the pump current and amplify the upstream optical signal according to the pump current.

The amplifying device according to claim 3, wherein the control information extracting unit (201) specifically comprises:

An optical receiver (204), configured to receive the downlink optical signal and convert the downlink optical signal into an electrical signal; The control unit (205) is configured to receive the electrical signal and extract control information from the electrical signal.

5. A method for amplifying a passive optical network, the method comprising: obtaining, according to a delay of an optical signal of each optical network unit to an upstream optical signal amplifier, and an uplink optical signal sent by each optical network unit Generating control information for controlling amplification of the upstream optical signal at different times of the upstream optical signal amplifier;

The method according to claim 5, wherein the method further comprises: allocating an uplink time slot to an uplink optical signal of each optical network unit according to a dynamic bandwidth allocation algorithm, according to the uplink time slot and each optical network The delay of the optical signal from the unit to the upstream optical signal amplifier is calculated at different times when the upstream optical signal sent by each optical network unit reaches the upstream optical signal amplifier.

The method according to claim 5, wherein the method further comprises: storing the control information in a list of gain values corresponding to different times when the upstream optical signal reaches the upstream optical signal amplifier, The gain value is proportional to the delay of the optical network unit corresponding to the upstream optical signal to the optical signal of the upstream optical signal amplifier.

The method according to any one of claims 5 to 7, wherein the method further comprises: extracting the control information before the uplink optical signal arrives at a corresponding time.

The method according to claim 5, wherein the method further comprises:

When the uplink optical signal arrives at the optical line terminal, the power information in the uplink optical signal is extracted, and the control information is adjusted according to the power information.

10. The method according to claim 5, wherein the step of receiving the downlink optical signal and extracting the control information, and generating a pump current for controlling the upstream optical signal amplifier according to the control information Specifically include: Receiving the downlink optical signal and converting the downlink optical signal into an electrical signal;

Extracting the control information from the electrical signal and storing it in an internal memory; generating a pump current regulation output according to the electrical signal;

The pump current of the upstream optical signal amplifier is adjusted according to the pump current adjustment amount.

11. A method of measuring a delay of an optical signal from a remote amplifier to an optical line termination, comprising the steps of:

The optical line terminal notifies an optical network unit to send uplink continuous light, and turns off all other optical network units;

The optical line terminal sends a downlink ranging authorization signal, and records an initial time T1;

The remote amplifier receives the downlink ranging grant signal and converts it into an electrical signal;

Parsing the outgoing ranging grant signal and suddenly changing the pump current significantly such that the upstream continuous light produces a burst of significant rising or falling edges;

When the optical line terminal detects that the continuous continuous light of the uplink generates a sudden rising edge or a falling edge, the time T2 at this time is recorded;

Calculate the round trip time of the remote amplifier to the optical line terminal as T2-T1, and the delay of the optical signal is (T2-T1) 12.