CN102511138B - Dimmable transceiver, passive optical network system and device - Google Patents

Abstract

The embodiment of the invention discloses an adjustable optical transceiver, which includes a laser amplifier, a first filter, a second filter, a receiver and a wavelength control module. A resonant cavity for laser oscillation is formed between the laser amplifier and the first filter, and an uplink optical signal emitted by the laser amplifier oscillates in the resonant cavity to form a laser output. The second filter is placed in the resonant cavity, transmits the first optical signal in the resonant cavity to the first filter, and reflects the second optical signal passing through the first filter to the receiver. The wavelength control module is used for performing wavelength selection on the first optical signal and the second optical signal respectively. The adjustable optical transceiver can realize simultaneous adjustment of uplink wavelength and downlink wavelength, and has a simple structure. The embodiment of the present invention also provides a passive optical network system and equipment.

Description

Dimmable transceiver, passive optical network system and equipment

technical field

The present invention relates to the technical field of optical fiber communication, in particular to an adjustable optical transceiver, and a passive optical network system and equipment.

Background technique

In the PON (Passive Optical Network, Passive Optical Network) system, by introducing the WDM (Wavelength Division Multiplexing, Wavelength Division Multiplexing) technology in the optical transmission network, several channels originally carried by separate optical fibers are multiplexed into the same root The transmission in the optical fiber greatly reduces the number of required optical fibers, so that the wavelength resources in a single optical fiber can be fully utilized.

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

Tunable lasers and tunable receivers are the key components of the wavelength division multiplexing technology in the backbone network. They can be adjusted to a specified wavelength in a certain transmission window without using multiple transmitters and receivers with different wavelengths. Machine can realize wavelength division multiplexing transmission. The emergence of tunable devices can be adjusted to the required wavelength according to needs, which greatly improves the flexibility of the network, and prevents device manufacturers from making a large number of devices with different wavelengths, reducing the inventory cost and operation and maintenance cost of equipment.

Currently, tunable lasers are generally used as transmitting devices for wavelength division multiplexing. The tunable laser works at a specific wavelength, and the wavelength can be tuned by auxiliary means, and the laser can be used to emit different wavelengths. For example, a tunable DFB (Distributed Feed Back, distributed feedback) laser is equipped with a reflector in the gain region of the resonator, and uses a thermoelectric cooler to change the temperature (or input current) of the resonator to tune the wavelength, which has better power output And fast enough frequency response characteristics, the technology is mature.

Currently, tunable receivers used for wavelength division multiplexing generally use a combination of tunable filters and photodetectors. The tunable filters select and pass specified wavelengths, and then the photodetectors receive them.

Integrating the transmitter and receiver together to become an optical transceiver device available in the access network requires that the optical component has a simple structure, easy assembly, and a simple controller. However, the existing tunable lasers need to use expensive refrigerators, and the adjustment speed is slow and the adjustment range is small; as the tuning temperature rises, its effective output power will decrease. Optical transceiver devices have a low integration level and a complex structure. The transmission and reception need to be controlled separately, and the uplink wavelength and downlink wavelength cannot be adjusted at the same time, and the cost is high.

Contents of the invention

An embodiment of the present invention proposes a tunable optical transceiver, which realizes simultaneous adjustment of uplink wavelength and downlink wavelength, and has a simple structure. The embodiment of the present invention also provides a passive optical network system and equipment.

The adjustable optical transceiver provided by the embodiment of the present invention includes a laser amplifier, a first filter, a second filter, a receiver, and a wavelength control module; the laser amplifier is used to amplify the first optical signal, and transmit the an amplified first optical signal; the first filter is located in the emission path of the laser amplifier, and the first filter is used to reflect the first optical signal back to the laser amplifier according to a first reflectivity, so that The first optical signal oscillates back and forth in the resonant cavity formed between the laser amplifier and the first filter, and transmits the first optical signal according to the first transmittance to form laser light; the second filter The device is located between the laser amplifier and the first filter, and is used to transmit the first optical signal in the resonant cavity to the first filter, and pass through the second optical signal of the first filter. The optical signal is reflected to the receiver; the receiver is located in the reflection optical path of the second filter, and is used to receive the second optical signal reflected by the second filter; the wavelength control module is used for Wavelength selection is performed on the first optical signal and the second optical signal, so as to lock the emission wavelength and the reception wavelength of the tunable optical transceiver to target emission wavelengths and target reception wavelengths respectively.

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 terminal and/or the optical network unit respectively include the above-mentioned adjustable optical transceiver.

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

The wavelength selection of the first optical signal allowed to be transmitted and the second optical signal received by the wavelength control module can realize the simultaneous adjustment of the uplink wavelength and the downlink wavelength without using an expensive refrigerator and has high thermal stability. The adjustable optical transceiver has a simple structure and low cost, and is suitable for an application scenario of an access network.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a structural diagram of a passive optical network system provided by an embodiment of the present invention;

Fig. 2 is a structural diagram of a dimmable transceiver provided by Embodiment 1 of the present invention;

FIG. 3 is a structural diagram of a dimmable optical transceiver provided in Embodiment 2 of the present invention;

Fig. 4 is the filter characteristic curve of filter 11 shown in Fig. 3;

Fig. 5 is the filtering characteristic curve of filter 12 shown in Fig. 3;

Fig. 6 is the filtering characteristic curve of filter 13 shown in Fig. 3;

Fig. 7 is the filter characteristic curve of filter 14 shown in Fig. 3;

Fig. 8 is a structural diagram of a dimmable optical transceiver provided by Embodiment 3 of the present invention;

Fig. 9 is the filtering characteristic curve of filter 21 shown in Fig. 8;

Fig. 10 is the filter characteristic curve of filter 22 shown in Fig. 8;

Fig. 11 is the filter characteristic curve of filter 23 shown in Fig. 8;

Fig. 12 is a structural diagram of a dimmable optical transceiver provided in Embodiment 4 of the present invention;

Fig. 13 is the filter characteristic curve of the upper surface of filter 32 shown in Fig. 12;

Fig. 14 is the filter characteristic curve of the lower surface of filter 32 shown in Fig. 12;

Fig. 15 is the overall filtering characteristic curve of the filter 32 shown in Fig. 12;

Fig. 16 is a structural diagram of a dimmable transceiver provided in Embodiment 5 of the present invention;

Fig. 17 is the filter characteristic curve of filter 41 shown in Fig. 16;

FIG. 18 is a filter characteristic curve of the filter 42 shown in FIG. 16 .

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection 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 the optical transceiver provided in this application can be applied. The passive optical network system 100 includes at least one optical line terminal (OLT, Optical Line Terminal) 110 , multiple optical network units (ONU) 120 and an optical distribution network (ODN, Optical Distribution Network) 130 . The optical line terminal 110 is connected to the plurality of optical network units 120 in a point-to-multipoint manner through the optical distribution network 130 . The optical line terminal 110 and the optical network unit 120 may use a TDM (Time Division Multiplex and Multiplexer, time division multiplexing) mechanism, a WDM mechanism, or a TDM/WDM hybrid mechanism for communication. Wherein, the direction from the OLT 110 to the ONU 120 is defined as the downlink direction, and the direction from the ONU 120 to the OLU 110 is defined as the uplink direction.

The passive optical network system 100 may be a communication network that does not require any active device to implement data distribution between the optical line terminal 110 and the optical network unit 120. In a specific embodiment, the optical line The data distribution between the terminal 110 and the optical network unit 120 may be implemented through a passive optical device (such as an optical splitter) 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, Broadband Passive Optical Network) system defined by the ITU-T G.983 standard, an ITU-T Gigabit passive optical network (GPON) system defined by G.984 series standards, Ethernet passive optical network (EPON, Ethernet Passive Optical Network) defined by IEEE 802.3ah standard, wavelength division multiplexing passive optical network (WDM PON) ) system or next-generation passive optical network (NGAPON system, such as XGPON system defined by ITU-T G.987 series standards, 10G EPON system defined by IEEE 802.3av standard, TDM/WDM hybrid PON system, etc.). The entire contents of various passive optical network systems defined by the above standards are incorporated in this application document by reference.

The OLT 110 is usually located at a central location (such as a Central Office, CO), which can manage the multiple ONUs 120 in a unified manner. The optical line terminal 110 may act as an intermediary between the optical network unit 120 and an upper-layer network (not shown), forwarding data received from the upper-layer network to the optical network unit 120 as downlink data, and forwarding the uplink data received from the optical network unit 120 to the upper layer network. The specific structural configuration of the optical line terminal 110 may vary depending on the specific type of the passive optical network 100. In one embodiment, the optical line terminal 110 may include an optical transceiver 200, and the optical transceiver The optical transceiver 200 may be a tunable optical transceiver provided by an embodiment of the present invention, and its emission wavelength and reception wavelength can be adjusted according to actual application requirements. The optical transceiver 200 can send a downlink data signal with a specific emission wavelength to the optical network unit 120 through the optical distribution network 130, and receive the signal from the optical network unit 120 through the optical distribution network with a specific receiving wavelength. 130 sends an uplink data signal. 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 process the uplink data signal received by the optical transceiver 200 data signal processing.

The optical network unit 120 may be disposed in user-side locations (such as a user premises) in a distributed manner. The optical network unit 120 may be a network device for communicating with the optical line terminal 110 and the user, specifically, the optical network unit 120 may act as a link between the optical line terminal 110 and the user The medium, for example, the ONU 120 may forward the downlink data received from the OLT 110 to the user, and forward the data received from the user to the OLT 110 as uplink data. The specific structural configuration of the optical network unit 120 may vary due to the specific type of the passive optical network 100. In one embodiment, the optical network unit 120 may include an optical transceiver 300, and the optical transceiver The optical transceiver 300 may be a tunable optical transceiver provided by an embodiment of the present invention, and its emission wavelength and reception wavelength may also be adjusted according to actual application requirements. The optical transceiver 300 can send the uplink data signal with a specific emission 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 with a specific receiving wavelength. The downlink data signal sent by 130 . 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 process the downlink data signal received by the optical transceiver 300 data signal processing.

It should be understood that in this application document, the structure of the optical network unit 120 is similar to that of an optical network terminal (Optical Network Terminal, ONT), so in the solution provided by this application document, the optical network unit and the optical network terminal can be mutually Change.

The optical distribution network 130 may be a data distribution system, which may include optical fibers, 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 equipment may be passive optical devices, specifically, the optical fiber, optical coupler, optical combiner The wave/demultiplexer, optical splitter and/or other devices may be devices that distribute data signals between the OLT 110 and the ONU 120 without power support. In addition, in other embodiments, the optical distribution network 130 may further include one or more processing devices, for example, optical amplifiers or relay devices (Relay devices). In the branch structure shown in Figure 1, the optical distribution network 130 can specifically extend from the optical line terminal 110 to the plurality of optical network units 120, but can also be configured as any other point-to-multipoint structure .

The implementation scheme of the dimmable optical transceiver provided by the present invention will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 2 , it is a structural diagram of a dimmable optical transceiver provided by 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 splitting filter 3, a receiver 4 and a wavelength control module. details as follows:

The laser amplifier 1 is used to amplify the optical signal and emit the amplified optical signal;

The external filter 2 is located on the emission path of the laser amplifier 1 and is coupled with an optical fiber or an optical fiber adapter.

When the adjustable optical transceiver is used as the optical transceiver of the optical network unit in the passive optical network system, the external filter 2 can be coupled to the branch optical fiber of the optical distribution network; alternatively, when the adjustable optical When the transceiver is used as the optical transceiver of the optical line terminal in the passive optical network system, the external filter 2 can be coupled to the main optical fiber of the optical distribution network.

For ease of understanding, the following embodiments are described by taking the tunable optical transceiver as an optical transceiver of an optical network unit in a passive optical network system as an example. Under this scenario, correspondingly, the laser amplifier 1 can control the uplink The optical signal is amplified, and the amplified uplink optical signal is transmitted, and the receiver 4 can receive the downlink 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 know that the structure and working principle of the adjustable optical transceiver provided in the following embodiments can be applied to the optical transceiver of the optical line terminal. In the case of a transceiver, the laser amplifier 1 transmits a downlink optical signal, while the receiver 4 receives an uplink optical signal transmitted by an optical network unit.

In a specific embodiment, a resonant cavity for laser oscillation can be formed between the laser amplifier 1 and the external filter 2; the external filter 2 is used to reflect the uplink optical signal back to the laser amplifier 1 according to the first reflectivity, so that the uplink optical signal is The resonant cavity formed between the laser amplifier 1 and the external filter 2 oscillates back and forth; and transmits the uplink 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 Downlink optical signal transmitted by optical fiber;

In an optional embodiment, the value range of the first reflectance is: 80%-90%; the value range of the first transmittance is 10%-20%, that is, the first transmittance is approximately equal to 1 minus first reflectivity.

The uplink and downlink splitting filter 3 is located between the laser amplifier 1 and the external filter 2, and is used to transmit the uplink optical signal in the resonator to the external filter 2, and reflect the downlink optical signal passing through the external filter 2 to the receiver 4;

In an optional implementation manner, the light receiving surface of the uplink and downlink splitting filter 3 and the light emitting path of the laser amplifier 1 form 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 reflection optical path of the uplink and downlink splitting filter 3, and is used to receive the downlink optical signal reflected by the uplink and downlink splitting filter 3;

On the one hand, the wavelength control module can be used to select the wavelength of the uplink optical signal in the resonant cavity, so as to lock the emission wavelength of the tunable optical transceiver to the target emission wavelength; The downlink optical signal of the transceiver is wavelength-selected so that the optical receiver 4 only receives the downlink optical signal with the target receiving wavelength, that is, the receiving wavelength of the tunable optical transceiver is locked to the target receiving wavelength.

In a specific embodiment, the wavelength control module may include an uplink wavelength adjuster 5 , a downlink wavelength adjuster 6 and a controller 7 .

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

The downlink wavelength adjuster 6 is used to select the wavelength of the downlink optical signal input to the adjustable optical transceiver, and lock the downlink optical signal with the target receiving wavelength to enter the receiver 4;

The controller 7 is used to send a frequency selection control signal to control the uplink wavelength adjuster 5 and the downlink wavelength adjuster 6 to perform wavelength selection.

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

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

The controller 7 is also used for receiving the optical power information fed back by the receiver 4, and controlling the uplink wavelength adjuster 5 to perform wavelength locking on the uplink optical signal by detecting the peak power of the downlink optical signal.

In an optional embodiment, the laser amplifier 1 is a reflective semiconductor amplifier (Reflective Semiconductor Optical Amplifier, RSOA), the uplink wavelength adjuster 5 is a tunable filter, and the downlink wavelength adjuster 6 is a tunable filter.

In the adjustable optical transceiver provided by the embodiment of the present invention, the controller controls the uplink wavelength adjuster and the downlink wavelength adjuster to select the wavelength of the optical signal that is allowed to pass through, and can realize the simultaneous adjustment of the uplink wavelength and the downlink wavelength without using expensive The refrigerator has high thermal stability; and by detecting the peak power of the downlink optical signal, the wavelength of the uplink optical signal can be locked, avoiding the use of expensive wave locking devices. The adjustable optical transceiver has a simple structure and low cost, and is suitable for an application scenario of an access network.

The structure of the dimmable optical transceiver provided by the embodiment of the present invention will be described in detail below with reference to FIGS. 3 to 18 .

Referring to FIG. 3 , it is a structural diagram of a dimmable optical transceiver provided by Embodiment 2 of the present invention.

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

In addition, the filter 11 is also coupled with an optical fiber or an optical fiber adapter, and the filter 11 is used to send an uplink optical signal to the optical fiber, such as the uplink wavelength band λ _u shown in FIG. 3 . Moreover, the filter 11 is also used to transparently transmit the downlink optical signal input through the optical fiber, such as the downlink wavelength band λ _d1 -λ _d4 shown in FIG. 3 . , collectively referred to as the downlink band λ _d .

The uplink and downlink spectroscopic filters of the adjustable optical transceiver are implemented by using fixed filters, such as the filter 12 shown in FIG. 3 . The filter 12 is located on the emission light path of the RSOA, and placed between the RSOA and the filter 11 . The filter 12 is used to transmit the uplink optical signal in the resonant cavity to the filter 11, and reflect the downlink optical signal passing through the filter 11 to the receiver Rx. During specific implementation, the light receiving surface of the filter 12 and the emitting light path of the RSOA form a first angle. The first angle may be 45 degrees, etc., and the specific angle may be set according to actual needs, and each angle corresponds to a certain transmittance.

The uplink wavelength adjuster of the tunable optical transceiver is realized by using a tunable filter, such as the filter 13 shown in FIG. 3 . The filter 13 is located on the emission path of the RSOA, and placed between the RSOA and the filter 12 . During specific implementation, the frequency selection of the filter 13 is controlled by the controller to select the wavelength of the uplink optical signal emitted by the RSOA, and lock the uplink optical signal oscillating in the resonant cavity to the target emission wavelength.

The downlink wavelength adjuster of the tunable optical transceiver is realized by using a tunable filter, such as the filter 14 shown in FIG. 3 . The filter 14 is located on the reflected optical path of the filter 12 and placed between the filter 12 and the receiver Rx. The filter 14 is used to lock the downlink optical signal of the target receiving wavelength into the receiver Rx.

Referring to FIG. 4 , it is a filtering characteristic curve of the filter 11 . The filter 11 has a reflectivity of 80% to 90% for the uplink band _λu , so the filter 11 can reflect most of the uplink optical signals back to the RSOA to form an oscillation in the resonant cavity. Only 10%-20% of the upstream optical power is transmitted through the filter 11 to form laser output.

Referring to FIG. 5 , it is a filtering characteristic curve of the filter 12 . The reflectance of the filter 12 to the uplink wavelength band _λu is 0, that is, all uplink optical signals pass through. The filter 12 has a reflectivity of 100% for the downlink wavelength band _λd , that is, all downlink optical signals are reflected to prevent the downlink optical signals from entering the RSOA, thereby realizing the uplink and downlink light splitting function.

Referring to FIG. 6 , it is a filtering characteristic curve of the filter 13 . The filter 13 is an adjustable filter. Under the control of the controller, the wavelength of the uplink optical signal that is allowed to pass is selected, for example, the uplink wavelength band _λu is selected to form an oscillation in the resonant cavity.

Referring to FIG. 7 , it is a filtering characteristic curve of the filter 14 . The filter 14 is an adjustable filter. Under the control of the controller, the wavelength of the downlink optical signal allowed to pass is selected, for example, the downlink wavelength band _λd1 is selected to enter the receiver Rx.

The working principle of the adjustable optical transceiver provided in this embodiment for transmitting uplink optical signals is as follows:

RSOA emits a beam of light with a wide range of wavelengths, that is, broadband light. After the broadband light passes through the filter 13 for wavelength selection, only the uplink band λ _u is transmitted to the filter 12 . The uplink band λ _u all passes through the filter 12 and is transmitted to the filter 11 . The filter 11 reflects 80% to 90% of the uplink optical signal to form an oscillation in the resonant cavity, and the rest of the uplink optical power is transmitted through the filter 11 to form a laser output.

The uplink optical signal reflected from the filter 11 all passes through the filter 12, enters the filter 13 for wavelength selection, and then returns to the RSOA for self-injection optical power amplification, and the amplified uplink optical signal is then transmitted from the RSOA to the filter The filter 13 repeats the above-mentioned process of wavelength selection by the filter 13, all passing through the filter 12, and then reaching the filter 11 for partial reflection, so that the laser light with the target emission wavelength is output from the filter 11.

The working principle of the adjustable optical transceiver provided in this embodiment for receiving downlink optical signals is as follows:

The downlink wavelength band λ _d input to the tunable optical transceiver through the optical fiber all passes through the filter 11 and reaches the filter 12 . The filter 12 reflects all the downlink band _λd and transmits it to the filter 14; the filter 14 selects the wavelength of the downlink optical signal, and selects the downlink band _λd1 with the target receiving wavelength to enter the receiver Rx.

During specific implementation, the adjustable optical transceiver provided in this embodiment can realize simultaneous adjustment of uplink wavelength and downlink wavelength by controlling and adjusting the frequency selection of the filter 13 and the filter 14 through the controller. Since the wavelength adjustment has nothing to do with the laser temperature, there is no need to use an expensive refrigerator, which not only reduces the cost, but also has high thermal stability.

In addition, in the adjustable optical transceiver provided in this embodiment, the controller adjusts the wavelength of the downlink optical signal allowed to pass through the filter 14, and finds the peak value of the downlink optical signal by detecting the change of the optical power received by the receiver Rx The optical power can ensure the wavelength alignment of the uplink optical signal, so that the downlink optical signal power can be used to lock the wavelength of the uplink optical signal, avoiding the use of expensive wave locking devices and saving costs.

Referring to FIG. 8 , it is a structural diagram of a dimmable optical transceiver provided by Embodiment 3 of the present invention.

The dimmable optical transceiver provided in the third embodiment integrates filters on the basis of the second embodiment above, so as to simplify the structure of the device.

In the adjustable optical transceiver provided in the third embodiment, the laser amplifier adopts the reflective semiconductor amplifier RSOA. The external filter of the adjustable optical transceiver adopts a fixed filter, such as the filter 21 shown in FIG. 8 . A resonant cavity for laser oscillation is formed between the RSOA and the filter 21 . In addition, the filter 21 is also coupled with an optical fiber or an optical fiber adapter. The function of the filter 21 is the same as that of the filter 11 in the second embodiment above, and will not be described again here.

The uplink and downlink spectroscopic filters of the adjustable optical transceiver are implemented by using fixed filters, such as the filter 23 shown in FIG. 8 . The installation position and working principle of the filter 23 are the same as those of the filter 12 in the second embodiment above, and will not be described here again.

Compared with the above-mentioned second embodiment, the difference of this third embodiment is that: the uplink wavelength adjuster and the downlink wavelength adjuster are integrated to form an integrated first tunable filter, as shown in FIG. 8 twenty two. The filter 22 is located on the emission light path of the RSOA, and placed between the filter 21 and the filter 23 .

Referring to FIG. 9 , it is a filtering characteristic curve of the filter 21 . The filter 21 has a reflectivity of 80% to 90% for the uplink wavelength band _λu , so the filter 21 can reflect most of the uplink optical signal back to the RSOA to form an oscillation in the resonant cavity. Only 10%-20% of the upstream optical power is transmitted through the filter 21 to form laser output.

Referring to FIG. 10 , it is a filtering characteristic curve of the filter 22 . In this embodiment, the uplink wavelength adjuster and the downlink wavelength adjuster are integrated on the filter 22 to form a tunable filter. The filter 22 has two transmission peaks, which respectively correspond to the target emission wavelength (ie, uplink wavelength) and the target reception wavelength (ie, downlink wavelength). When the filter 22 is adjusted, the two transmission peaks move simultaneously, which ensures the adjustment consistency of the uplink wavelength and the downlink wavelength, so that the uplink wavelength can be locked by the downlink received optical power.

Referring to FIG. 11 , it is a filtering characteristic curve of the filter 23 . The reflectance of the filter 23 to the uplink wavelength band _λu is 0, that is, all uplink optical signals pass through. The filter 23 has a reflectivity of 100% for the downlink band _λd , that is, all downlink optical signals are reflected, preventing the downlink optical signals from entering the RSOA, thereby realizing the uplink and downlink light splitting function.

The tunable optical transceiver provided in the third embodiment integrates the uplink wavelength adjuster and the downlink wavelength adjuster into one tunable filter, further simplifies the device structure and circuit control, and ensures the consistency of uplink and downlink wavelength adjustment. By detecting the peak power of the downlink optical signal, the wavelength alignment of the uplink optical signal can be ensured, so that the wavelength of the uplink optical signal can be locked by using the power of the downlink optical signal.

Referring to FIG. 12 , it is a structural diagram of a dimmable optical transceiver provided by Embodiment 4 of the present invention.

The dimmable optical transceiver provided in the fourth embodiment is based on the third embodiment above, and the filter is further integrated to simplify the structure of the device.

In the adjustable optical transceiver provided in the fourth embodiment, the laser amplifier adopts the reflective semiconductor amplifier RSOA. The external filter of the adjustable optical transceiver adopts a fixed filter, such as the filter 31 shown in FIG. 12 . A resonant cavity for laser oscillation is formed between the RSOA and the filter 31 . In addition, the filter 31 is also coupled with an optical fiber or an optical fiber adapter. The function of the filter 31 is the same as that of the filter 21 in the third embodiment above, and will not be described again here.

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

Referring to FIG. 13 , it is a filter characteristic curve of the upper surface of the filter 32 . The upper surface of the filter 32 is coated with a transmissive film, and its filtering characteristics are shown in FIG. 13 . In this embodiment, the controller controls the filter 32, and by adjusting the filter 32 to change the transmitted wavelength, the emission wavelength can be adjusted to realize the function of an adjustable transmitter.

Referring to FIG. 14 , it is a filter characteristic curve of the lower surface of the filter 32 . The lower surface of the filter 32 is coated with a reflective film, and its filtering characteristics are shown in FIG. 14 . In this embodiment, the controller controls the filter 32, and by adjusting the filter 32 to change the reflected wavelength, the downlink optical signal of a specified wavelength can be reflected into the receiver, realizing the function of an adjustable receiver.

Referring to FIG. 15 , it is the overall filtering characteristic curve of the filter 32 .

In the tunable optical transceiver provided in Embodiment 4, the uplink wavelength adjuster and downlink wavelength adjuster are integrated on the uplink and downlink optical splitting filters to form an integrated tunable filter, which further simplifies the structure of the device and reduces the optical The complexity of device assembly, and further reduce the cost. In Embodiment 4, by detecting the peak power of the downlink optical signal, the power of the downlink optical signal can also be used to lock the wavelength of the uplink optical signal. The principle is the same as that of Embodiment 3 above.

Referring to FIG. 16 , it is a structural diagram of a dimmable optical transceiver provided by Embodiment 5 of the present invention.

The dimmable optical transceiver provided in the fifth embodiment is based on the third embodiment above, and the filter is further integrated to simplify the structure of the device.

Compared with the third embodiment above, the fifth embodiment differs in that: the uplink wavelength adjuster and the downlink wavelength adjuster are integrated into the external filter to form an integrated third tunable filter, as shown in Figure 16 filter 41.

In the adjustable optical transceiver provided in the fifth embodiment, the laser amplifier adopts a reflective semiconductor amplifier RSOA; a resonant cavity for laser oscillation is formed between the RSOA and the filter 41 .

In the adjustable optical transceiver provided in Embodiment 5, the uplink and downlink splitting filters are implemented by fixed filters, such as the filter 42 shown in FIG. 16 . The installation position and working principle of the filter 42 are the same as those of the filter 23 in the third embodiment above, and will not be described here again.

Referring to FIG. 17 , it is a filtering characteristic curve of the filter 41 . The filter 41 is an adjustable filter, and under the control of the controller, the wavelength of the uplink optical signal that is allowed to pass is selected. Moreover, while the filter 41 performs wavelength selection on the uplink optical signal, the reflectivity for the uplink wavelength band _λu is 80% to 90%, reflecting most of the uplink optical signal back to the RSOA, thereby forming an oscillation in the resonant cavity, The rest of the uplink optical power is transmitted through the filter 41 to form laser output. In addition, for the downlink wavelength, under the control of the controller, the filter 41 selects the wavelength of the downlink optical signal that is allowed to pass through, and only transmits the downlink optical signal with the target receiving wavelength.

Referring to FIG. 18 , it is a filtering characteristic curve of the filter 42 . The reflectance of the filter 42 to the uplink wavelength band _λu is 0, that is, all uplink optical signals pass through. The filter 42 has a reflectivity of 100% for the downlink wavelength band _λd , that is, all downlink optical signals are reflected to prevent the downlink optical signals from entering the RSOA, thereby realizing the uplink and downlink optical splitting function.

In the tunable optical transceiver provided in Embodiment 5, the uplink wavelength adjuster and downlink wavelength adjuster are integrated on the external filter to form an integrated tunable filter, which further simplifies the structure of the device and reduces the cost of optical device assembly. complexity and further reduce costs. In Embodiment 5, by detecting the peak power of the downlink optical signal, the power of the downlink optical signal can also be used to lock the wavelength of the uplink optical signal. The principle is the same as that of Embodiment 3 above.

In the adjustable optical transceiver provided by the embodiment of the present invention, a laser amplifier and an external filter are selected to form a resonant cavity for laser oscillation, and an upstream optical signal of a specific wavelength is locked by an upstream wavelength adjuster to oscillate in the resonant cavity, and finally a laser is formed. output. The uplink and downlink optical splitting filters are inserted into the resonant cavity to separate the uplink and downlink optical signals, and the downlink optical signals of a specific wavelength are locked by the downlink wavelength adjuster to enter the receiver. In the embodiment of the present invention, the controller controls the uplink wavelength adjuster and the downlink wavelength adjuster to select the wavelength of the optical signal that is allowed to pass through, so that the uplink wavelength and the downlink wavelength can be adjusted simultaneously without using expensive refrigerators, and the thermal stability is high. ; And by detecting the peak power of the downlink optical signal, the wavelength of the uplink optical signal can be locked, avoiding the use of expensive wave locking devices. The adjustable optical transceiver has a simple structure and low cost, and is suitable for an application scenario of an access network.

The above description is a preferred embodiment of the present invention, and it should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also considered Be the protection scope of the present invention.

Claims (10)

1. 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 used to amplify the first optical signal and emit the amplified first optical signal; The first filter is located in the emission optical path of the laser amplifier, and the first filter is used to reflect the first optical signal back to the laser amplifier according to the first reflectivity, so that the first optical signal is The 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 laser light; The second filter is located between the laser amplifier and the first filter, and is used to transmit the first optical signal in the resonant cavity to the first filter, and will pass through the first optical signal reflecting the second optical signal of the filter to the receiver; The receiver is located in the reflection optical path of the second filter, and is used to receive the second optical signal reflected by the second filter; The wavelength control module is used to perform wavelength selection on the first optical signal and the second optical signal, so as to lock the emission wavelength and reception wavelength of the tunable optical transceiver to the target emission wavelength and target reception wavelength respectively. wavelength. 2. The tunable optical transceiver according to claim 1, wherein the wavelength control module comprises a first wavelength adjuster, a second wavelength adjuster and a controller; The first wavelength adjuster is used to perform wavelength selection on the uplink optical signal emitted by the laser amplifier, and lock the first optical signal oscillating in the resonant cavity to the target emission wavelength; The second wavelength adjuster is used to select the wavelength of the downlink optical signal input to the tunable optical transceiver, and lock the second optical signal with the target receiving wavelength to enter the receiver; The controller is used to send a frequency selection control signal to control the first wavelength adjuster and the second wavelength adjuster to perform wavelength selection. 3. The adjustable optical transceiver according to claim 2, wherein the receiver is further configured to feed back the optical power information of the received downlink optical signal to the controller; The controller is further configured to receive the 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 the peak power of the downlink optical signal. 4. The tunable optical transceiver according to claim 3, wherein both the first wavelength adjuster and the second wavelength adjuster are tunable filters. 5. The adjustable optical transceiver according to claim 4, wherein the first filter is a fixed filter; The first wavelength adjuster is located in the emission path of the laser amplifier and placed between the laser amplifier and the second filter; The second wavelength adjuster is located in the reflected optical path of the second filter, and is placed between the second filter and the receiver. 6. The adjustable 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 to form a Integrated first adjustable filter; The first tunable filter is located in the emission path of the laser amplifier, and placed between the first filter and the second filter. 7. The adjustable optical transceiver according to 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 to form an integrated second adjustable filter. 8. The tunable optical transceiver according to claim 4, wherein the first wavelength adjuster and the second wavelength adjuster are integrated into the first filter to form an integrated third Adjustable filter. 9. A passive optical network system, characterized in that it includes 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 unit, wherein the optical line terminal comprises the dimmable optical transceiver according to claim 1, and the optical network unit comprises the dimmable optical transceiver according to any one of claims 1-8. 10. A passive optical network device, characterized in that it includes an optical transceiver and a data processing module, the optical transceiver is used to transmit a first data signal using a target transmitting wavelength, and to receive a second data signal using a target receiving wavelength; The data processing module is used to provide the first data signal to the optical transceiver, and process the second data signal received by the optical transceiver; wherein, the optical transceiver is as claimed in the claims The dimmable transceiver described in any one of 1 to 8.