WO2013091190A1

WO2013091190A1 - Adjustable optical transceiver, passive optical network system and device

Info

Publication number: WO2013091190A1
Application number: PCT/CN2011/084348
Authority: WO
Inventors: 钱银博; 周小平; 欧鹏; 彭桂开; 付生猛
Original assignee: 华为技术有限公司
Priority date: 2011-12-21
Filing date: 2011-12-21
Publication date: 2013-06-27
Also published as: CN102511138B; CN102511138A

Abstract

Disclosed in an embodiment of the present invention is an adjustable optical transceiver, comprising a laser amplifier, a first filter, a second filter, a receiver and a wavelength control module. The resonant cavity of a laser oscillation is formed between the laser amplifier and the first filter, and the uplink optical signal transmitted by the laser amplifier oscillates in the resonant cavity forming laser output. The second filter is disposed in the resonant cavity and transmits the first optical signal in the resonant cavity to the first filter, and reflects the second optical signal having passed through the first filter to the receiver. The wavelength control module is used to select wavelength for the first optical signal and the second optical signal respectively. The adjustable optical transceiver can simultaneously adjust the uplink wavelength and the downlink wavelength, and has a simple structure. Further provided in the embodiment of the present invention are a passive optical network system and device.

Description

Dimmable transceiver, passive optical network system and equipment

The present invention relates to the field of optical fiber communication technologies, and in particular, to a tunable optical transceiver, and a passive optical network system and device. Background technique

In a PON (Passive Optical Network) system, a number of channels originally carried by a single optical fiber are multiplexed into the same root by introducing WDM (Wavelength Division Multiplexing) technology in an optical transmission network. Transmission in the fiber greatly reduces the number of fibers required, making full use of the wavelength resources in a single fiber.

Applying WDM technology to the access network can effectively improve the communication capacity of the access system, and its advantages are obvious. However, the WDM technology is widely used in the access network. The first thing that needs to be solved is the low-cost optical transceiver device that can be used for wavelength division multiplexing, especially the optical transceiver device that can be used in an ONU (Optical Network Unit). .

The tunable laser and tunable receiver are key components of the WDM technology in the backbone network. They can be adjusted to a specified wavelength in a certain transmission window without using multiple transmitters and receivers of different wavelengths. Wavelength division multiplexing transmission can be realized by the machine. The appearance of tunable devices can be adjusted to the required wavelengths as needed, greatly increasing the flexibility of the network, and eliminating the need for device manufacturers to make a large number of devices of different wavelengths, reducing the inventory cost and operation and maintenance cost of the device.

Current illuminating devices for wavelength division multiplexing generally use tunable lasers. The tunable laser operates at a specific wavelength, and the wavelength can be tuned by an auxiliary means, using a laser to emit different wavelengths. For example, a tunable DFB (Distributed Feed Back) laser has a mirror in the gain region of the cavity. The thermoelectric cooler is used to change the temperature (or input current) of the cavity to tune the wavelength, resulting in better power output. And the frequency response characteristics are fast enough, and the technology is mature.

Currently, tunable receivers for wavelength division multiplexing generally use a combination of a tunable filter and a photodetector, which is selected by a tunable filter to pass through a specified wavelength and then received by a photodetector. The transmitter and the receiver are integrated to form an optical transceiver device usable in the access network, and the optical component is required to have a simple structure, easy assembly, and simple controller. However, existing tunable lasers require the use of expensive chillers, and the adjustment speed is slow and the adjustment range is small; as the tuning temperature increases, the effective output power decreases. The optical transceiver device has low integration degree and complicated structure, and the transmission and reception need to be separately controlled, and the uplink wavelength and the downlink wavelength cannot be simultaneously adjusted, and the cost is high. Summary of the invention

The embodiment of the invention provides a tunable optical transceiver, which simultaneously adjusts the uplink wavelength and the downlink wavelength, and has a simple structure. Embodiments of the present invention also provide a passive optical network system and device.

The tunable optical transceiver provided by the embodiment of the invention includes a laser amplifier, a first filter, a second filter, a receiver and a wavelength control module; the laser amplifier is used for amplifying the first optical signal, and transmitting the An enlarged first optical signal; the first filter is located at an emission path of the laser amplifier, and the first filter is configured to reflect the first optical signal back to the laser amplifier according to a first reflectance, so that The first optical signal oscillates back and forth between a resonant cavity formed between the laser amplifier and the first filter, and transmits the laser light according to a first transmittance to form a laser; the second filtering Between the laser amplifier and the first filter for transmitting a first optical signal within the resonant cavity to the first filter and to pass a second of the first filter An optical signal is reflected to the receiver; the receiver is located in a reflected optical path of the second filter, and is configured to receive a second optical signal reflected by the second filter; Control means for said first optical signal and said second optical wavelength selection signal, respectively, to the emission wavelength and the wavelength tunable light receiving transceivers are locked to the target wavelength and the target emission wavelength reception.

The passive optical network system provided by the embodiment of the present invention includes an optical line terminal and a plurality of optical network units, wherein the optical line terminal is connected to the plurality of optical network units in a point-to-multipoint manner through an optical distribution network. Wherein the optical line termination and/or the optical network unit respectively comprise a tunable optical transceiver as described above.

The passive optical network device provided by the embodiment of the present invention includes: an optical transceiver and a data processing module, where the optical transceiver is configured to transmit a first data signal by using a target transmit wavelength, and receive a second data signal by using a target receive wavelength; The data processing module is configured to provide the first data signal to the light Transceiver, and processing a second data signal received by the optical transceiver; wherein the optical transceiver is a tunable optical transceiver as described above.

The wavelength control module selects the wavelength of the first optical signal and the received second optical signal that are allowed to be transmitted, so that the upstream wavelength and the downstream wavelength can be simultaneously adjusted, and an expensive refrigerator is not required, and the thermal stability is high. The tunable optical transceiver has a simple structure and low cost, and is suitable for an access network application scenario. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any inventive labor.

1 is a structural diagram of a passive optical network system according to an embodiment of the present invention;

2 is a structural diagram of a tunable optical transceiver according to Embodiment 1 of the present invention;

3 is a structural diagram of a tunable optical transceiver according to Embodiment 2 of the present invention;

Figure 4 is a filter characteristic curve of the filter 11 shown in Figure 3;

Figure 5 is a filter characteristic curve of the filter 12 shown in Figure 3;

Figure 6 is a filter characteristic curve of the filter 13 shown in Figure 3;

Figure 7 is a filter characteristic curve of the filter 14 shown in Figure 3;

8 is a structural diagram of a tunable optical transceiver according to Embodiment 3 of the present invention;

Figure 9 is a filter characteristic curve of the filter 21 shown in Figure 8;

Figure 10 is a filter characteristic curve of the filter 22 shown in Figure 8;

Figure 11 is a filter characteristic curve of the filter 23 shown in Figure 8;

12 is a structural diagram of a tunable optical transceiver according to Embodiment 4 of the present invention;

Figure 13 is a filter characteristic curve of the upper surface of the filter 32 shown in Figure 12;

Figure 14 is a filter characteristic curve of the lower surface of the filter 32 shown in Figure 12;

Figure 15 is an overall filter characteristic curve of the filter 32 shown in Figure 12;

16 is a structural diagram of a tunable optical transceiver according to Embodiment 5 of the present invention;

Figure 17 is a filter characteristic curve of the filter 41 shown in Figure 16; Fig. 18 is a filter characteristic curve of the filter 42 shown in Fig. 16. detailed description

BRIEF DESCRIPTION OF THE DRAWINGS The technical solutions in the embodiments of the present invention will be described in detail with reference to the accompanying drawings. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative work are within the scope of the present invention.

Please refer to FIG. 1 , which is a schematic diagram of a network architecture of a passive optical network (PON ) system to which an optical transceiver provided by the present application is applicable. The passive optical network system 100 includes at least one optical line terminal (OLT) 110, a plurality of optical network units (ONUs) 120, and an optical distribution network (ODN) 130. The terminal 110 is connected to the plurality of optical network units 120 in a point-to-multipoint manner through the optical distribution network 130. TDM (Time Division Multiplex and can be used between the optical line terminal 110 and the optical network unit 120 Multiplexer, time division multiplexing) mechanism, WDM mechanism or TDM/WDM hybrid mechanism for communication. The direction from the optical line terminal 110 to the optical network unit 120 is defined as a downlink direction, and from the optical network unit 120. The direction to the optical line terminal 110 is the upward direction.

The passive optical network system 100 can be a communication network that does not require any active devices to implement data distribution between the optical line terminal 110 and the optical network unit 120. In a specific embodiment, the optical line Data distribution between the terminal 110 and the optical network unit 120 can be implemented by passive optical devices (such as optical splitters) in the optical distribution network 130. The passive optical network system 100 may be an Asynchronous Transfer Mode Passive Optical Network (ATM PON) system or a Broadband Passive Optical Network (BPON) system defined by the ITU-T G.983 standard, ITU-T. Gigabit Passive Optical Network (GPON) system defined by the G.984 series of standards, Ethernet Passive Optical Network (EPON) defined by the IEEE 802.3ah standard, and wavelength division multiplexing passive optical network (WDM PON) System or next-generation passive optical network (NGA PON system, such as XGPON system defined by ITU-T G.987 series standard, 10G EPON system defined by IEEE 802.3av standard, TDM/WDM hybrid PON system, etc.). The entire contents of the various passive optical network systems defined by the above-mentioned standards are incorporated herein by reference. The optical line terminations 110 are typically located at a central location (e.g., Central Office, CO) that can collectively manage the plurality of optical network units 120. The optical line terminal 110 may serve as a medium between the optical network unit 120 and an upper layer network (not shown), and forward data received from the upper layer network to the optical network unit 120 as downlink data, and The uplink data received from the optical network unit 120 is forwarded to the upper layer network. The specific configuration of the optical line terminal 110 may vary depending on the specific type of the passive optical network 100. In an embodiment, the optical line terminal 110 may include an optical transceiver 200, and the optical transceiver The modulating device 200 can be a tunable optical transceiver provided by the embodiment of the present invention, and the transmitting wavelength and the receiving wavelength can be adjusted according to actual application requirements. The optical transceiver 200 can transmit a downlink data signal having a specific transmission wavelength to the optical network unit 120 through the optical distribution network 130, and receive the optical network unit 120 through the optical distribution network by using a specific receiving wavelength. 130 uplink data signal transmitted. Moreover, in a specific embodiment, the optical line terminal 110 may further include a data processing module, configured to provide the downlink data signal to the optical transceiver 200, and receive the uplink received by the optical transceiver 200. The data signal is processed.

The optical network unit 120 can be distributedly disposed at a user side location (such as a customer premises). The optical network unit 120 may be a network device for communicating with the optical line terminal 110 and a user. Specifically, the optical network unit 120 may serve as the optical line terminal 110 and the user. The medium, for example, the optical network unit 120 may forward the downlink data received from the optical line terminal 110 to the user, and forward the data received from the user to the optical line terminal 110 as uplink data. The specific configuration of the optical network unit 120 may be different depending on the specific type of the passive optical network 100. In an embodiment, the optical network unit 120 may include an optical transceiver 300, and the optical transceiver The modulating device 300 can be a tunable optical transceiver provided by the embodiment of the present invention, and the transmitting wavelength and the receiving wavelength can also be adjusted according to actual application requirements. The optical transceiver 300 can transmit an uplink data signal having a specific transmission wavelength to the optical line terminal 110 through the optical distribution network 130, and receive the optical line terminal 110 through the optical distribution network by using a specific receiving wavelength. 130 downlink data signal transmitted. Moreover, in a specific embodiment, the optical network unit 120 may further include a data processing module, configured to provide the uplink data signal to the optical transceiver 300, and receive the downlink received by the optical transceiver 300. The data signal is processed.

It should be understood that, in the present application, the structure of the optical network unit 120 and the optical network terminal (Optical Network Terminal, ONT) is similar, so in the solution provided in this application, the optical network unit and the optical network terminal can be interchanged.

The optical distribution network 130 can be a data distribution system that can include fiber optics, optical couplers, optical multiplexers/demultiplexers, optical splitters, and/or other devices. In one embodiment, the optical fiber, optical coupler, optical multiplexer/demultiplexer, optical splitter, and/or other device may be a passive optical device, specifically, the optical fiber, optical coupler, and photosynthetic The wave/demultiplexer, optical splitter, and/or other device may be a device that distributes data signals between the optical line terminal 110 and the optical network unit 120 without the need for power support. Additionally, in other embodiments, the optical distribution network 130 may also include one or more processing devices, such as optical amplifiers or relay devices. In the branching structure shown in FIG. 1, the optical distribution network 130 may specifically extend from the optical line terminal 110 to the plurality of optical network units 120, but may be configured as any other point-to-multipoint structure. . The implementation of the tunable optical transceiver provided by the present invention is described in detail below with reference to the accompanying drawings.

Referring to FIG. 2, it is a structural diagram of a tunable optical transceiver according to Embodiment 1 of the present invention.

The tunable optical transceiver provided in Embodiment 1 includes: a laser amplifier 1, an external filter 2, an uplink and downlink spectral filter 3, a receiver 4, and a wavelength control module. details as follows:

The laser amplifier 1 is for amplifying the optical signal and transmitting the amplified optical signal; the external filter 2 is located on the emission path of the laser amplifier 1 and coupled to the optical fiber or the optical fiber adapter.

When the tunable optical transceiver is used as an optical transceiver of an optical network unit in a passive optical network system, the external filter 2 may be coupled to a branch fiber of the optical distribution network; alternatively, when the dimming When the transceiver is an optical transceiver of an optical line termination in a passive optical network system, the external filter 2 can be coupled to a backbone optical fiber of the optical distribution network.

For ease of understanding, the following embodiment describes the tunable optical transceiver as an optical transceiver of an optical network unit in a passive optical network system. In this scenario, correspondingly, the laser amplifier 1 can be uplinked. The optical signal is amplified and the amplified upstream optical signal is transmitted, and the receiver 4 can receive the downstream optical signal transmitted by the optical line terminal and transmitted through the optical distribution network. It should be understood that those skilled in the art can understand the structure of the tunable optical transceiver provided by the following embodiments. The working principle can be applied to the optical transceiver of the optical line terminal. The main difference is that when applied to the optical transceiver of the optical line terminal, the laser amplifier 1 transmits a downlink optical signal, and the receiver 4 receives the optical network unit. The transmitted upstream optical signal.

In a specific embodiment, a resonant cavity of laser oscillation may be formed between the laser amplifier 1 and the external filter 2; the external filter 2 is configured to reflect the upstream optical signal back to the laser amplifier 1 according to the first reflectance, so that the upstream optical signal is a resonant cavity formed between the laser amplifier 1 and the external filter 2 reciprocates; and transmits the upstream optical signal according to the first transmittance to form a laser output to the optical fiber; on the other hand, the external filter 2 can also be used for transmission from Downstream optical signal from optical fiber transmission;

In an optional embodiment, the first reflectance ranges from 80% to 90%; the first transmittance ranges from 10% to 20%, that is, the first transmittance is approximately equal to 1 minus First reflectivity.

The uplink and downlink spectral filter 3 is located between the laser amplifier 1 and the external filter 2 for transmitting the upstream optical signal in the resonant cavity to the external filter 2, and reflecting the downstream optical signal passing through the external filter 2 to the receiver. 4;

In an alternative embodiment, the light receiving surface of the upstream and downstream spectral filters 3 and the optical path of the laser amplifier 1 are at a first angle. The first angle may be 45 degrees or the like, and the specific angle may be set according to actual needs.

The receiver 4 is located on the reflected optical path of the uplink and downlink spectral filter 3, and is configured to receive the downlink optical signal reflected by the uplink and downlink spectral filter 3;

The wavelength control module can be used on the one hand to select a wavelength of the upstream optical signal in the resonant cavity to lock the emission wavelength of the tunable optical transceiver to the target emission wavelength; and on the other hand to input the dimming light to the dimming The downstream optical signal of the transceiver is wavelength selected such that the optical receiver 4 receives only the downstream optical signal having the target receiving wavelength, that is, the receiving wavelength of the tunable optical transceiver is locked to the target receiving wavelength.

In a particular embodiment, the wavelength control module can include an upstream wavelength adjuster 5, a downstream wavelength adjuster 6 and a controller 7.

The upstream wavelength adjuster 5 is configured to perform wavelength selection on the uplink optical signal emitted by the laser amplifier 1, and lock the upstream optical signal oscillating in the resonant cavity to the target emission wavelength;

The downstream wavelength adjuster 6 is configured to perform wavelength selection on a downlink optical signal input to the tunable optical transceiver. Locking the downstream optical signal having the target receiving wavelength into the receiver 4;

The controller 7 is configured to issue a frequency selective control signal, and control the upstream wavelength adjuster 5 and the downstream wavelength adjuster 6 to perform wavelength selection.

Further, the tunable optical transceiver provided in this embodiment also performs the lock wave on the uplink wavelength by detecting the downlink received optical power, as follows:

The receiver 4 is further configured to feed back the optical power information of the received downlink optical signal to the controller 7;

The controller 7 is further configured to receive the optical power information fed back by the receiver 4, and control the upstream wavelength adjuster 5 to perform wavelength locking on the upstream optical signal by detecting the peak power of the downlink optical signal.

In an alternative embodiment, the laser amplifier 1 is a Reflective Semiconductor Optical Amplifier (RSOA), the upstream wavelength adjuster 5 is a tunable filter, and the downstream wavelength adjuster 6 is a tunable filter.

The tunable optical transceiver provided by the embodiment of the invention controls the upstream wavelength adjuster and the downlink wavelength adjuster to select the wavelength of the optical signal that is allowed to pass, and can simultaneously adjust the uplink wavelength and the downlink wavelength, and does not need to be expensive. The chiller has high thermal stability; and by detecting the peak power of the downstream optical signal, the wavelength of the upstream optical signal can be locked, avoiding the use of expensive lock-wave devices. The tunable optical transceiver has a simple structure and low cost, and is suitable for an access network application scenario. The structure of the tunable optical transceiver provided by the embodiment of the present invention is described in detail below with reference to FIG. 3 to FIG.

3 is a structural diagram of a tunable optical transceiver according to Embodiment 2 of the present invention.

In this embodiment, the laser amplifier of the tunable optical transceiver employs a reflective semiconductor amplifier RSOA. The external filter of the tunable transceiver uses a fixed filter, such as filter 11 shown in Figure 3. Among them, the fixed filter means that the wavelength of the optical signal allowed to pass is fixed and not adjustable. A resonant cavity of laser oscillation is formed between the RSOA and the filter 11.

In addition, the filter 11 is also coupled to an optical fiber or fiber optic adapter for transmitting an upstream optical signal to the optical fiber, such as the upstream band λ shown in FIG. Moreover, the filter 11 is also used to transparently transmit the downstream optical signal input through the optical fiber, as shown in the downlink bands _dl to _d4 shown in FIG. , collectively referred to as the downlink band _d .

The upper and lower splitting filters of the tunable optical transceiver are implemented by using a fixed filter, as shown in FIG. Filter 12. The filter 12 is located on the transmitting optical path of the RSOA and is placed between the RSOA and the filter 11. The filter 12 is for transmitting the upstream optical signal in the resonant cavity to the filter 11, and reflecting the downstream optical signal passing through the filter 11 to the receiver Rx. In a specific implementation, the light receiving surface of the filter 12 and the emitting optical path of the RSOA are at a first angle. The first angle may be 45 degrees or the like, and the specific angle may be set according to actual needs, and each angle corresponds to a certain transmittance.

The upstream wavelength adjuster of the tunable transceiver is implemented using a tunable filter, such as filter 13 shown in FIG. The filter 13 is located on the transmitting optical path of the RSOA and is placed between the RSOA and the filter 12. In a specific implementation, the filter 13 is controlled by the controller to select a frequency, select a wavelength of the uplink optical signal emitted by the RSOA, and lock the upstream optical signal oscillated in the resonant cavity to the target emission wavelength.

The downstream wavelength adjuster of the tunable optical transceiver is implemented using a tunable filter, such as filter 14 shown in FIG. The filter 14 is located on the reflected light path of the filter 12 and is placed between the filter 12 and the receiver Rx. The filter 14 is used to lock the downstream optical signal of the target reception wavelength into the receiver Rx.

Referring to Fig. 4, it is a filter characteristic curve of the filter 11. The filter 11 has a reflectivity of 80% to 90% for the upstream band λ, so the filter 11 can reflect most of the upstream optical signal back to the RSOA, forming an oscillation in the resonant cavity. Only 10% to 20% of the upstream optical power is transmitted from the filter 11 to form a laser output.

Referring to FIG. 5, it is a filter characteristic curve of the filter 12. The reflectance of the filter 12 for the upstream band λ is zero, that is, the upstream optical signals are all passed. The reflectivity of the filter 12 to the downlink band _d is 100%, that is, the downlink optical signals are all reflected, and the downlink optical signal is prevented from entering the RSOA, thereby implementing the uplink and downlink splitting functions.

See Fig. 6, which is the filter characteristic curve of the filter 13. The filter 13 is a tunable filter that selects the wavelength of the upstream optical signal that is allowed to pass under the control of the controller, for example, selecting the upstream band λ to form an oscillation in the resonant cavity.

Referring to Figure 7, is a filter characteristic curve of the filter 14. The filter 14 is a tunable filter that, under the control of the controller, selects the wavelength of the downstream optical signal that is allowed to pass, for example, selecting the downstream band _{dl to} enter the receiver Rx.

The working principle of the tunable optical transceiver provided by this embodiment for transmitting an uplink optical signal is as follows:

The RSOA emits a beam of light with a wide range of wavelengths, ie broad spectrum light. After the wide spectrum light is wavelength-selected by the filter 13, only the upstream band λ is transmitted to the filter 12. Upstream band λ all passed filter The wave filter 12 is transmitted to the filter 11. The filter 11 reflects 80% to 90% of the upstream optical signal to form an oscillation in the resonant cavity, and the remaining upstream optical power is transmitted from the filter 11 to form a laser output.

The upstream optical signal reflected from the filter 11 passes through the filter 12, enters the filter 13 for wavelength selection, returns to the RSOA for self-injection optical power amplification, and the amplified upstream optical signal is transmitted from the RSOA to the filter. The filter 13 repeats the above-described filter 13 for wavelength selection, passes through the filter 12, and reaches the filter 11 to perform partial reflection, thereby outputting laser light having the target emission wavelength from the filter 11.

Tunable optical transceiver provided in the present embodiment, which receives the downstream optical signals works as follows: by downlink band tunable optical input to the optical transceiver person ₍₁ through a filter 11 to reach the filter 12. The filter 12 The downlink band _{d is} totally reflected and transmitted to the filter 14; the filter 14 selects the wavelength of the downstream optical signal, and selects the downlink band λ _dl having the target receiving wavelength to enter the receiver Rx.

In a specific implementation, the tunable optical transceiver provided in this embodiment controls the adjustment filter 13 and the filter 14 by the controller, and can simultaneously adjust the uplink wavelength and the downlink wavelength. Since the wavelength adjustment is independent of the laser temperature, it is not necessary to use an expensive refrigerator, which not only reduces the cost but also has high thermal stability.

In addition, in the tunable optical transceiver provided by the embodiment, the wavelength of the downlink optical signal allowed by the filter 14 is adjusted by the controller, and the peak value of the downlink optical signal is found by detecting the change of the optical power received by the receiver Rx. The optical power can ensure the wavelength alignment of the upstream optical signal, thereby locking the wavelength of the upstream optical signal by using the downlink optical signal power, thereby avoiding the use of an expensive lock wave device and saving cost. FIG. 8 is a structural diagram of a tunable optical transceiver according to Embodiment 3 of the present invention.

The tunable optical transceiver provided in the third embodiment is based on the second embodiment described above, and the filter is integrated to simplify the structure of the device.

The tunable optical transceiver provided in the third embodiment has a laser amplifier using a reflective semiconductor amplifier RSOA. The external filter of the tunable transceiver uses a fixed filter, such as filter 21 shown in FIG. A resonant cavity of laser oscillation is formed between the RSOA and the filter 21. In addition, the filter 21 is also coupled to an optical fiber or fiber optic adapter. The filter 21 has the same function as the filter 11 of the second embodiment described above, and is no longer Description.

The upper and lower splitting filters of the tunable transceiver are implemented using a fixed filter, such as filter 23 shown in Figure 8. The installation position and working principle of the filter 23 are the same as those of the filter 12 of the second embodiment described above, and will not be described here.

Compared with the second embodiment, the third embodiment has the following differences: the upstream wavelength adjuster and the downstream wavelength adjuster are integrated to form an integrated first tunable filter, as shown in FIG. twenty two. The filter 22 is located on the transmitting optical path of the RSOA and is placed between the filter 21 and the filter 23.

See Fig. 9, which is the filter characteristic curve of the filter 21. The filter 21 has a reflectivity of 80% to 90% for the upstream band λ, so the filter 21 can reflect most of the upstream optical signal back to the RSOA, forming an oscillation in the resonant cavity. Only 10% to 20% of the upstream optical power is transmitted from the filter 21 to form a laser output.

Referring to Fig. 10, it is a filter characteristic curve of the filter 22. In this embodiment, an upstream wavelength adjuster and a downstream wavelength adjuster are integrated on the filter 22 to form a tunable filter. Filter 22 has two transmission peaks corresponding to the target emission wavelength (i.e., the upstream wavelength) and the target reception wavelength (i.e., the downstream wavelength). When the filter 22 is adjusted, the two transmission peaks are simultaneously moved to ensure the consistency of the adjustment of the upstream wavelength and the downstream wavelength, so that the upstream wavelength is locked by the downlink received optical power.

Referring to Fig. 11, it is a filter characteristic curve of the filter 23. The filter 23 has a reflectance of 0 for the upstream band λ, that is, the entire upstream optical signal passes. The reflectivity of the filter 23 to the downlink band λ _ύ is 100%, that is, all the downlink optical signals are reflected, and the downstream optical signal is prevented from entering the RSOA, thereby realizing the uplink and downlink splitting functions.

The tunable optical transceiver provided in the third embodiment integrates the upstream wavelength adjuster and the downstream wavelength adjuster in a tunable filter, further simplifying device structure and circuit control, and ensuring consistency of uplink and downlink wavelength adjustment. By detecting the peak power of the downlink optical signal, the wavelength of the upstream optical signal can be aligned, and the wavelength of the upstream optical signal is locked by the downlink optical signal power. Referring to FIG. 12, it is a structural diagram of a tunable optical transceiver according to Embodiment 4 of the present invention.

The tunable optical transceiver provided in the fourth embodiment is further integrated on the filter based on the third embodiment to simplify the structure of the device. The tunable optical transceiver provided in the fourth embodiment has a laser amplifier using a reflective semiconductor amplifier

RSOA. The external filter of the tunable transceiver uses a fixed filter, such as filter 31 shown in Figure 12. A resonant cavity of laser oscillation is formed between the RSOA and the filter 31. In addition, filter 31 is also coupled to an optical fiber or fiber optic adapter. The filter 31 has the same function as the filter 21 of the above-described third embodiment and will not be described here.

Compared with the third embodiment, the fourth embodiment is different in that: the uplink wavelength adjuster and the downlink wavelength adjuster are integrated on the uplink and downlink splitting filters to form an integrated second tunable filter, as shown in FIG. 12 . Filter 32 is shown. The filter 32 is located on the transmitting path of the RSOA and is placed between the RSOA and the filter 31. The installation position of the filter 32 is the same as that of the filter 23 of the above-described third embodiment, and will not be described here.

Referring to Fig. 13, is a filter characteristic curve of the upper surface of the filter 32. The upper surface of the filter 32 is plated with a transmissive film, and its filtering characteristics are as shown in FIG. In this embodiment, the filter 32 is controlled by the controller, and the wavelength of the transmission is changed by the adjustment filter 32 to adjust the emission wavelength to realize the function of the adjustable transmitter.

Referring to Fig. 14, is a filter characteristic curve of the lower surface of the filter 32. The lower surface of the filter 32 is plated with a reflective film, and its filtering characteristics are as shown in Fig. 14. In this embodiment, the filter 32 is controlled by the controller, and the reflected wavelength is changed by the adjustment filter 32 to reflect the downstream optical signal of the specified wavelength into the receiver to realize the function of the tunable receiver.

Referring to Figure 15, is the overall filter characteristic of filter 32.

The tunable optical transceiver provided in the fourth embodiment integrates the upstream wavelength adjuster and the downlink wavelength adjuster on the uplink and downlink splitting filters to form an integrated tunable filter, which further simplifies the structure of the device and reduces the light. The complexity of device assembly and further reduced costs. In the fourth embodiment, by detecting the peak power of the downlink optical signal, the wavelength of the uplink optical signal can be locked by using the downlink optical signal power, and the principle is the same as that of the third embodiment. Referring to FIG. 16, FIG. 16 is a structural diagram of a tunable optical transceiver according to Embodiment 5 of the present invention.

The tunable optical transceiver provided in the fifth embodiment is further integrated on the basis of the above-mentioned third embodiment to further simplify the structure of the device.

Compared with the third embodiment, the difference of the fifth embodiment is as follows: the upstream wavelength adjuster and the lower The line wavelength adjuster is integrated onto the external filter to form an integrated third tunable filter, such as filter 41 shown in FIG.

The tunable optical transceiver provided in the fifth embodiment has a laser amplifier using a reflective semiconductor amplifier RSOA; a resonant cavity for forming a laser oscillation between the RSOA and the filter 41.

In the tunable optical transceiver provided in the fifth embodiment, the uplink and downlink optical splitting filters are implemented by using a fixed filter, such as the filter 42 shown in FIG. The installation position and working principle of the filter 42 are the same as those of the filter 23 of the third embodiment described above, and will not be described here.

See Fig. 17, which is the filter characteristic curve of the filter 41. The filter 41 is a tunable filter that selects the wavelength of the upstream optical signal that is allowed to pass under the control of the controller. Moreover, the filter 41 performs wavelength selection on the upstream optical signal, and has a reflectance of 80% to 90% for the upstream band λ, and reflects most of the upstream optical signal back to the RSOA, thereby forming an oscillation in the resonant cavity. The remaining upstream optical power is transmitted from filter 41 to form a laser output. In addition, for the downstream wavelength, the filter 41 also selects the wavelength of the downstream optical signal that is allowed to pass under the control of the controller, and only transmits the downstream optical signal having the target receiving wavelength.

Referring to Fig. 18, it is a filter characteristic curve of the filter 42. The reflectance of the filter 42 for the upstream band λ is 0, that is, the upstream optical signals are all passed. The reflectivity of the filter 42 to the downlink band λ _ύ is 100%, that is, all the downlink optical signals are reflected, and the downstream optical signal is prevented from entering the RSOA, thereby implementing the uplink and downlink splitting functions.

The tunable optical transceiver provided in the fifth embodiment integrates the upstream wavelength adjuster and the downstream wavelength adjuster on the external filter to form an integrated tunable filter, which further simplifies the structure of the device and reduces the assembly of the optical device. The complexity and further reduced costs. In the fifth embodiment, by detecting the peak power of the downlink optical signal, the wavelength of the uplink optical signal can also be locked by using the downlink optical signal power, and the principle is the same as that of the foregoing implementation 3. The tunable optical transceiver provided by the embodiment of the invention selects a laser amplifier and an external filter to form a resonant cavity of the laser oscillation, and the upstream optical signal locked by the upstream wavelength adjuster oscillates in the resonant cavity, and finally forms a laser. Output. An uplink and downlink spectral filter is inserted in the resonant cavity to separate the uplink and downlink optical signals, and the downstream optical modulator locks the downstream optical signal of a specific wavelength into the receiver. In the embodiment of the present invention, the controller controls the uplink wavelength adjuster and the downlink wavelength adjuster to allow passage. The wavelength of the optical signal is selected to enable simultaneous adjustment of the upstream wavelength and the downstream wavelength, without using an expensive refrigerator, and having high thermal stability; and by detecting the peak power of the downstream optical signal, the wavelength of the upstream optical signal can be locked. Avoid using expensive lock-wave devices. The tunable optical transceiver has a simple structure and low cost, and is suitable for an access network application scenario. The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. These improvements and retouchings are also considered. It is the scope of protection of the present invention.

Claims

Rights request

A tunable optical transceiver, comprising: a laser amplifier, a first filter, a second filter, a receiver, and a wavelength control module;

The laser amplifier is configured to amplify the first optical signal and emit the amplified first optical signal;

The first filter is located at an emission path of the laser amplifier, and the first filter is configured to reflect the first optical signal back to the laser amplifier according to a first reflectance, so that the first optical signal is a resonant cavity formed between the laser amplifier and the first filter oscillates back and forth, and transmits the first optical signal according to a first transmittance to form a laser;

The second filter is located between the laser amplifier and the first filter for transmitting a first optical signal in the resonant cavity to the first filter, and will pass the first A second optical signal of the filter is reflected to the receiver;

The receiver is located at a reflected optical path of the second filter, and configured to receive a second optical signal reflected by the second filter;

The wavelength control module is configured to separately perform wavelength selection on the first optical signal and the second optical signal to lock the transmit wavelength and the receive wavelength of the tunable optical transceiver to a target transmit wavelength and target reception, respectively. wavelength.

2. The tunable optical transceiver of claim 1, wherein the wavelength control module comprises a first wavelength adjuster, a second wavelength adjuster, and a controller;

The first wavelength adjuster is configured to perform wavelength selection on an uplink optical signal emitted by the laser amplifier, and lock a first optical signal oscillated in the resonant cavity at a target emission wavelength;

The second wavelength adjuster is configured to perform wavelength selection on a downlink optical signal input to the tunable optical transceiver, and lock a second optical signal having a target receiving wavelength into the receiver;

The controller is configured to send a frequency selective control signal, and control the first wavelength adjuster and the second wavelength adjuster to perform wavelength selection.

The tunable optical transceiver according to claim 2, wherein the receiver is further configured to feed back optical power information of the received downlink optical signal to the controller;

The controller is further configured to receive optical power information fed back by the receiver, and control the first wavelength adjuster to perform wavelength locking on the uplink optical signal by detecting a peak power of the downlink optical signal.

4. The tunable optical transceiver of claim 3, wherein the first wavelength adjuster and the second wavelength adjuster are both tunable filters.

5. The tunable optical transceiver of claim 4, wherein the first filter is a fixed filter;

The first wavelength adjuster is located at an emission path of the laser amplifier and is disposed between the laser amplifier and the second filter;

The second wavelength adjuster is located in a reflected optical path of the second filter and is disposed between the second filter and the receiver.

The tunable optical transceiver according to claim 4, wherein the first filter is a fixed filter; the first wavelength adjuster and the second wavelength adjuster are integrated into one, and the Integrated first tunable filter;

The first tunable filter is located in an emission path of the laser amplifier and is disposed between the first filter and the second filter.

7. The tunable optical transceiver of claim 4, wherein the first filter is a fixed filter; the first wavelength adjuster, the second wavelength adjuster, and the second The filters are integrated into one and form an integrated second tunable filter.

8. The tunable optical transceiver of claim 4, wherein the first wavelength adjuster and the second wavelength adjuster are integrated on the first filter to form an integrated third Adjustable filter.

A passive optical network system, comprising: an optical line terminal and a plurality of optical network units, wherein the optical line terminal is connected to the plurality of optical networks in a point-to-multipoint manner through an optical distribution network The unit, wherein the optical line terminal and/or the optical network unit respectively comprise the tunable optical transceiver of any of claims 1-8.

A passive optical network device, comprising: an optical transceiver and a data processing module, wherein the optical transceiver is configured to transmit a first data signal by using a target transmission wavelength, and receive a second data signal by using a target receiving wavelength; The data processing module is configured to provide the first data signal to the optical transceiver, and process a second data signal received by the optical transceiver; wherein the optical transceiver is as claimed The tunable optical transceiver of any of 1 to 8.