Optical system, optical transmitter and optical network equipment

Abstract

The utility model provides an optical system, an optical transmitter and optical network equipment, and belongs to the technical field of optical communication. The optical system comprises a plurality of lasers, a laser driving unit and a modulation unit; the working wavelengths of at least two of the plurality of lasers are different, and each working wavelength corresponds to one working mode of the optical system; the plurality of lasers are electrically connected with the laser driving unit, the laser driving unit is used for receiving a mode selection signal, and the mode selection signal is used for indicating the current working mode of the optical system. The laser driving unit is also used for driving the laser corresponding to the working mode indicated by the mode selection signal to work; the plurality of lasers are also electrically connected with the modulation unit, and the modulation unit is used for modulating light emitted by the working lasers into optical signals carrying information. According to the invention, the internal structure of the ONU can be simplified.

Description

Technical Field

[0001] The present disclosure relates to the field of optical communication technologies, and particularly to an optical system, an optical transmitter, and an optical network device. Background Art

[0002] A passive optical network (PON) is a fiber-based communication technology widely used in scenarios such as fiber to the building (FTTB), fiber to the home (FTTH), and fiber to the room (FTTR). Its core feature is that an optical line terminal (OLT) arranged in a central computer room establishes an optical communication connection with an optical network unit (ONU) arranged on the user side through an optical distribution network (ODN).

[0003] Currently, in large-scale network deployments based on PON technology, there are situations where multiple generations of network communications coexist, such as the coexistence of network communications such as GPON, 10GPON, and 50GPON. Some users want to upgrade to higher-bandwidth network communications, while some users do not want to upgrade to higher-bandwidth network communications. Then, the ONU arranged on the user side needs to have multiple working modes. Such an ONU is called a multi-mode ONU and internally integrates multiple sets of optical transceiver systems.

[0004] There are multiple sets of optical transceiver systems in the multi-mode ONU, which makes the multi-mode ONU include more components and greatly increases its complexity. Therefore, how to simplify the internal structure of the multi-mode ONU is an urgent problem to be solved. Summary of the Utility Model

[0005] The present disclosure provides an optical system, an optical transmitter, and an optical network device. The optical system is specifically a multi-mode optical system, which includes a smaller number of components and is applied in an ONU, which is beneficial to simplifying the internal structure of the ONU.

[0006] In a first aspect, the present disclosure provides an optical system, the optical system includes a plurality of lasers, a laser driving unit, and a modulation unit;

[0007] The operating wavelengths of at least two of the plurality of lasers are different, and each operating wavelength corresponds to a working mode of the optical system;

[0008] The multiple lasers are all electrically connected to the laser driving unit. The laser driving unit is configured to receive a mode selection signal, where the mode selection signal is used to indicate the working mode in which the optical system is currently operating. The laser driving unit is further configured to drive the lasers corresponding to the working mode indicated by the mode selection signal to operate;

[0009] The multiple lasers are also all electrically connected to the modulation unit. The modulation unit is configured to modulate the light emitted by the operating lasers into an optical signal carrying information.

[0010] In the solution shown in the present disclosure, the lasers corresponding to different working modes of the multi-mode optical system use the same laser driving unit to start operating and also use the same modulation unit to modulate the emitted light into an optical signal carrying information. Compared with the lasers corresponding to different working modes using different laser driving units to start operating and different modulation units to modulate the emitted light into an optical signal, it is beneficial to reduce the components in the optical system and simplify the internal structure of the optical system. Then, when this optical system is applied in an ONU, it is beneficial to simplify the internal structure of the ONU and reduce its complexity.

[0011] Among them, the fact that the operating wavelengths of at least two of the above-mentioned lasers are different means that at least two of the lasers belong to different working modes, rather than the difference in operating wavelengths caused by errors.

[0012] In a possible implementation manner, the optical system further includes a multiplexer. Lasers with different operating wavelengths are located on the demultiplexing optical paths of the multiplexer, and an optical port of the optical system is located on the multiplexing optical path of the multiplexer.

[0013] In the solution shown in the present disclosure, lasers with different operating wavelengths transmit optical signals outward through a single optical port of the optical system, and each operating wavelength represents a working mode of the optical system. Therefore, different working modes use the same optical port for signal transmission. Then, when a user changes the working mode of the optical system, there is no need to plug and unplug the optical fiber to change the optical port. Thus, the multi-mode switching function of the optical system can be achieved without plugging and unplugging the optical fiber to change the optical port, improving the application flexibility of the optical network device where the optical system is located.

[0014] In a possible implementation manner, the laser driving unit and the modulation unit are integrated in the same driving chip.

[0015] In the solution shown in the present disclosure, since the laser driving unit is used to provide a DC voltage to the laser to excite the laser to operate, and the modulation unit is used to provide a high-speed AC voltage to the laser to load the transmitted information in the laser emitted by the laser, therefore, both the laser driving unit and the modulation unit input voltage to the laser. Then, the laser driving unit and the modulation unit can be integrated into the same driving chip, and this driving chip can be called an optophysical chip.

[0016] In a possible implementation, the laser driving unit includes a plurality of first connection terminals, a second connection terminal, and a first switch;

[0017] The first switch has a plurality of input terminals and a plurality of output terminals. The plurality of first connection terminals are electrically connected to the plurality of input terminals of the first switch one by one. The plurality of output terminals of the first switch are electrically connected to the first poles of the plurality of lasers one by one. The second poles of the plurality of lasers are all electrically connected to the second connection terminal;

[0018] The plurality of first connection terminals are all used to input DC voltage. The second connection terminal is used to output DC voltage. And among the plurality of first connection terminals, there are a target connection terminal and non-target connection terminals. The laser electrically connected to the target connection terminal can operate, and the laser electrically connected to the non-target connection terminal cannot operate;

[0019] The first switch is used to receive a mode selection signal and, based on the operating mode indicated by the mode selection signal, control the first pole of the corresponding laser to be electrically connected to the target connection terminal, and control the first poles of other lasers to be electrically connected to the non-target connection terminals.

[0020] In the solution shown in the present disclosure, the voltage applied across the two ends of the laser electrically connected to the target connection terminal is greater than the turn-on voltage of this laser. Therefore, the laser electrically connected to the target connection terminal can operate, that is, can emit light. The voltage applied across the two ends of the laser electrically connected to the non-target connection terminal is less than the turn-on voltage of this laser. Therefore, the laser electrically connected to the non-target connection terminal cannot emit light. Therefore, the first switch can realize the excitation and light emission of lasers in multiple operating modes by switching which laser is electrically connected to the target connection terminal, and share a laser driving unit.

[0021] In a possible implementation, the laser driving unit further includes a third connection terminal and a second switch;

[0022] The third connection terminal is electrically connected to the input terminal of the second switch. The plurality of output terminals of the second switch are electrically connected to the first poles of the plurality of lasers one by one;

[0023] The second switch is configured to receive the mode selection signal and control the first pole of the corresponding laser to be electrically connected to the third connection terminal based on the operating mode indicated by the mode selection signal;

[0024] When the optical system does not emit an optical signal, the first connection terminal is used to input a DC voltage, and the third connection terminal is used to output a DC voltage; when the optical system emits an optical signal, both the first connection terminal and the third connection terminal are used to input a DC voltage, and the second connection terminal is used to output a DC voltage.

[0025] Wherein, the multiple output terminals of the second switch are electrically connected to the first poles of the multiple lasers one by one. For example, each output terminal of the second switch is electrically connected to the line between the first pole of a laser and an output terminal of the first switch.

[0026] In the solution shown in the present disclosure, when the laser does not need to emit light, the first switch is also in the closed state, and there is current passing through the circuit. When the laser needs to emit light, because there is always current in the circuit where the first switch is located, the current can be quickly delivered to the laser connected to the target connection terminal, so that the laser can be quickly turned on to emit light. Conversely, the laser can also be quickly turned off.

[0027] In a possible implementation manner, after the second poles of the multiple lasers are connected in sequence, they are connected to the second connection terminal.

[0028] In the solution shown in the present disclosure, the second pole of the laser can be the cathode of the laser. The connection method in which the cathodes of multiple lasers are connected in sequence and then electrically connected to the second connection terminal belongs to the common cathode connection. Of course, the cathodes of multiple lasers can also be electrically connected to the second connection terminal respectively.

[0029] In a possible implementation manner, the second pole of the laser can also be the anode of the laser. The connection method in which the anodes of multiple lasers are connected in sequence and then electrically connected to the second connection terminal belongs to the common anode connection. Of course, the anodes of multiple lasers can also be electrically connected to the second connection terminal respectively.

[0030] In a possible implementation manner, after the first poles of the multiple lasers are connected in sequence, they are connected to the modulation unit, and a capacitor is arranged on the line between the first poles of two lasers; after the second poles of the multiple lasers are connected in sequence, they are connected to the modulation unit; the modulation unit is configured to input an AC voltage to the multiple lasers to modulate the light emitted by the working lasers into an optical signal carrying information.

[0031] Among them, the first terminal is a DC terminal, and the terminals on the modulation unit are AC terminals. The current between the laser and the first terminal belongs to a DC circuit. The circuit between the laser and the modulation unit belongs to an AC circuit.

[0032] In the solution shown in the present disclosure, since the first poles of multiple lasers are electrically connected to multiple first terminals one by one through first switches, and the first poles of multiple lasers are electrically connected in sequence, in this way, the first poles of all lasers can be electrically connected to the same first terminal. For this reason, a capacitor is arranged on the connection line between the first poles of any two lasers. Based on the characteristic of the capacitor that blocks DC and allows AC to pass through, thus, in the DC circuit, multiple lasers are isolated from each other, and in the AC circuit, multiple lasers are connected in parallel to two terminals of the modulation unit.

[0033] In a possible implementation manner, the optical system further includes multiple detectors and a transimpedance amplifier;

[0034] At least two detectors among the multiple detectors have different operating wavelengths, and each operating wavelength corresponds to an operating mode of the optical system;

[0035] The transimpedance amplifier includes an output terminal, multiple input terminals, and a third switch. The output terminal of the third switch is electrically connected to the output terminal of the transimpedance amplifier. The multiple input terminals of the third switch are electrically connected to the multiple input terminals of the transimpedance amplifier one by one. The multiple input terminals of the transimpedance amplifier are also electrically connected to the multiple detectors one by one;

[0036] The third switch is used to receive the mode selection signal, and based on the operating mode indicated by the mode selection signal, control the corresponding detector to be electrically connected to the output terminal of the transimpedance amplifier, so that the transimpedance amplifier amplifies and outputs the electrical signal of the detector corresponding to the operating mode indicated by the mode selection signal.

[0037] In the solution shown in the present disclosure, multiple detectors share one transimpedance amplifier. Compared with one detector using one transimpedance amplifier, the number of transimpedance amplifiers can be reduced, thereby reducing the electronic components in the optical transceiver system and simplifying the internal structure of the optical transceiver system. When this optical transceiver system is applied in an ONU, it is beneficial to simplify the internal structure of the ONU.

[0038] In a second aspect, an optical transmitter is provided, and the optical transmitter can be applied in the optical system described in the first aspect or any one of the first aspect;

[0039] The optical transmitter includes multiple lasers, multiple fourth terminals, a fifth terminal, and a sixth terminal;

[0040] The first poles of the multiple lasers are electrically connected to the multiple fourth connection terminals one by one, and the multiple fourth connection terminals are used to be electrically connected to a laser driving unit;

[0041] The first poles of the multiple lasers are also all electrically connected to the fifth connection terminal, and the fifth connection terminal is used to be electrically connected to a modulation unit;

[0042] The second poles of the multiple lasers are all electrically connected to the sixth connection terminal, and the sixth connection terminal is used to be respectively electrically connected to the laser driving unit and the modulation unit.

[0043] In the solution shown in the present disclosure, the optical transmitter can be applied to the optical system described above. Then, the multiple fourth connection terminals are electrically connected to the multiple output terminals of the first switch of the laser driving unit one by one, so as to realize the one-to-one electrical connection between the first poles of the multiple lasers and the multiple output terminals of the first switch. The sixth connection terminal is electrically connected to the second connection terminal of the laser driving unit, so as to realize that the second poles of the multiple lasers are all electrically connected to the second connection terminal. The fifth connection terminal and the sixth connection terminal are also both connected to the modulation unit, so as to realize that the first poles of the multiple lasers are all electrically connected to one connection terminal of the modulation unit, and the second poles of the multiple lasers are all electrically connected to another connection terminal of the modulation unit.

[0044] In the solution shown in the present disclosure, encapsulating multiple lasers on one optical transmitter, making the multiple lasers as one component, and connecting them to the optical system through the external connection terminals of the optical transmitter further simplifies the circuit layout inside the optical system, making the circuit inside the optical system more concise. The optical system including such an optical transmitter is applied to an ONU, further simplifying the internal structure of the ONU.

[0045] In a possible implementation manner, after the first poles of the lasers are connected in sequence, they are electrically connected to the fifth connection terminal, and a capacitor is arranged on the connection line between the first poles of two lasers.

[0046] In the solution shown in the present disclosure, the capacitor used to isolate multiple lasers from each other in the DC circuit and connect them in parallel with each other in the AC circuit is also integrated on the optical transmitter.

[0047] In a possible implementation manner, an inductor is arranged on the line between the first pole of the laser and the fourth connection terminal and at a position close to the fourth connection terminal.

[0048] In the solution shown in the present disclosure, based on the characteristics of the inductor of passing DC and blocking AC, passing low-frequency and blocking high-frequency, arranging an inductor on the DC circuit between the first pole of the laser and the fourth connection terminal can prevent the high-speed AC signal input from the fifth connection terminal from flowing into the DC circuit through the fourth connection terminal.

[0049] In a third aspect, an optical network device is provided. The optical network device includes a media access control chip and the optical system described in the first aspect. Both the laser driving unit and the modulation unit of the optical system are electrically connected to the media access control chip. Description of the Drawings

[0050] Figure 1 is a schematic diagram of the architecture of passive optical network communication provided by an exemplary embodiment of the present disclosure;

[0051] Figure 2 is a schematic diagram of an optical system provided by an exemplary embodiment of the present disclosure to achieve multiple working modes;

[0052] Figure 3 is a schematic circuit diagram of a laser operating in different working modes provided by an exemplary embodiment of the present disclosure, driven by the same laser driving unit and the same modulation unit;

[0053] Figure 4 is a schematic diagram of the current flowing in the circuit when the optical system provided by an exemplary embodiment of the present disclosure does not emit an optical signal;

[0054] Figure 5 is a schematic diagram of the current flowing in the circuit when the optical system provided by an exemplary embodiment of the present disclosure emits an optical signal;

[0055] Figure 6 is a schematic circuit diagram of detectors corresponding to different working modes provided by an exemplary embodiment of the present disclosure, with the electrical signals amplified by the same transimpedance amplifier;

[0056] Figure 7 is a schematic circuit diagram of an optical system provided by an exemplary embodiment of the present disclosure to achieve multiple working modes on the transmitting side and the receiving side;

[0057] Figure 8 is a schematic diagram of the architecture of passive optical network communication provided by another exemplary embodiment of the present disclosure;

[0058] Figure 9 is a partial schematic diagram of a multi-mode optical system provided by an exemplary embodiment of the present disclosure with a main optical port and a standby optical port;

[0059] Figure 10 is a schematic circuit diagram of an optical system provided by an exemplary embodiment of the present disclosure with a main optical port and a standby optical port to achieve multiple working modes;

[0060] Figure 11 is a schematic diagram of multiple lasers integrated on a silicon wafer provided by an exemplary embodiment of the present disclosure;

[0061] Figure 12Schematic diagram of multiple lasers integrated on a silicon wafer provided by another exemplary embodiment of the present disclosure;

[0062] Figure 13 Schematic diagram of multiple lasers and a multiplexer integrated on a silicon wafer provided by an exemplary embodiment of the present disclosure;

[0063] Figure 14 Schematic diagram of the structure of an optical transmitter formed by packaging multiple lasers provided by an exemplary embodiment of the present disclosure.

[0064] Description of reference numerals

[0065] 1. Laser; 11. First laser; 12. Second laser; 13. Third laser; 14. Fourth laser; 15. Fourth terminal; 16. Fifth terminal; 17. Sixth terminal. 2. Laser driving unit; 21. First terminal; 211. Target terminal; 212. Non-target terminal; 22. Second terminal; 23. Third terminal. 3. Modulation unit. 4. Detector; 41. First detector; 42. Second detector; 43. Third detector; 44. Fourth detector. 5. Transimpedance amplifier. 6. Limiting amplifier. 7. Multiplexer; 71. First multiplexer; 72. Second multiplexer. Detailed implementation manners

[0066] To make the objectives, technical solutions, and advantages of the present disclosure clearer, the following will further describe the embodiments of the present disclosure in detail with reference to the accompanying drawings.

[0067] This embodiment relates to an optical network device in a passive optical network (PON) system, and particularly to an optical transceiver system within the optical network device.

[0068] As Figure 1 shown, it is a schematic diagram of the architecture of PON network communication. Refer to Figure 1As shown in the figure, the optical line terminal (OLT) arranged in the central computer room establishes an optical communication connection with the optical network unit (ONU) arranged on the user side through the optical distribution network (ODN). The ODN includes a passive optical splitter for optical power distribution, a backbone optical fiber connected between the passive optical splitter and the OLT, and a branch optical fiber connected between the passive optical splitter and the ONU. When transmitting the downstream signal, the downstream signal sent by the OLT is transmitted to each ONU through the optical splitter, and the ONU selectively receives the downstream data belonging to itself in the downstream signal. When transmitting the upstream signal, the upstream signals sent by multiple ONUs are combined by the optical splitter into a single optical signal and transmitted to the OLT.

[0069] With the rapid upgrade of network bandwidth, there are currently situations where multiple generations of network communications such as GPON, 10GPON, and 50GPON coexist in PON network communications. Therefore, there are ONUs that implement GPON network communication, ONUs that implement 10GPON, and ONUs that implement 50GPON deployed on the user side.

[0070] In order to avoid the situation of having to replace the ONU when the user's network bandwidth is upgraded later, the functions of implementing multiple generations of network communications can be integrated into one ONU, making the ONU a multi-mode ONU. This kind of ONU includes multiple working modes, and each working mode corresponds to a type of PON network communication.

[0071] In this way, the multi-mode ONU needs to include multiple sets of optical transceiver systems inside to implement multiple working modes, increasing the complexity inside the ONU.

[0072] Therefore, this embodiment provides an optical system, specifically a multi-mode optical system. The lasers corresponding to different working modes use the same laser driving unit to start working, and also use the same modulation unit to modulate the emitted light into an optical signal carrying information. Compared with the lasers corresponding to different working modes using different laser driving units to start working and using different modulation units to modulate the emitted light into an optical signal, it is beneficial to reduce the components in the optical system and simplify the circuit relationship inside the optical system.

[0073] Among them, the optical system provided in this embodiment can be applied to the above-mentioned multi-mode ONU, can also be applied to a multi-mode optical module, and can also be applied to a multi-mode optical network terminal (ONT). This embodiment does not limit the application scenarios of the optical system, and the example in the text is the application in the ONU.

[0074] Among them, the optical system can be an optical emission system, which only includes the emission side and does not include the reception side. In this case, the optical system can be an optical emission system applied in an optical emission module. The optical system can also be an optical transceiver system, which not only includes the emission side but also the reception side. In this case, the optical system can be applied in the optical transceiver system of an optical transceiver module and can also be applied in the optical transceiver system of an ONU.

[0075] Next, the characteristics of the optical system will be introduced by taking the application of the optical system in the optical transceiver system of an ONU as an example.

[0076] As Figure 2 shown, it is a schematic structural diagram of the optical system. Referring to Figure 2 shown, the optical system includes a laser 1, a laser driving unit 2, and a modulation unit 3. Among them, the number of lasers 1 is multiple, and at least two of the multiple lasers 1 have different operating wavelengths, and each operating wavelength corresponds to an operating mode of the optical system.

[0077] Among them, the operating mode of the optical system refers to the transmission rate and bandwidth supported by the optical system in PON network communication.

[0078] For example, the optical system includes an operating mode supporting 10GPON network communication (denoted as the 10GPON operating mode) and an operating mode supporting 50GPON network communication (denoted as the 50GPON operating mode). Generally, the operating mode of the optical system and the operating wavelength of the laser (i.e., the wavelength of the light emitted by the laser) are in one-to-one correspondence. For example, in the 10GPON operating mode, the operating wavelength of the laser is 1270nm, and in the 50GPON operating mode, the operating wavelength of the laser is 1286nm.

[0079] Therefore, in a multimode optical system with multiple operating modes, the number of lasers 1 is multiple, and at least two of the multiple lasers have different operating wavelengths. In this embodiment, for the convenience of introduction, a dual-mode optical system is taken as an example. The number of lasers is two, which are respectively denoted as the first laser 11 and the second laser 12. The operating wavelengths of the first laser 11 and the second laser 12 are different. For example, the first laser 11 operates in the first operating mode, and the second laser 12 operates in the second operating mode.

[0080] It should be noted that the different operating wavelengths of the two lasers described in this embodiment mean that the operating modes to which the two lasers belong are different, rather than the different operating wavelengths of the two lasers caused by error conditions. Similarly, the same operating wavelengths of the two lasers described in this embodiment mean that the operating modes to which the two lasers belong are the same.

[0081] For example, if two lasers belong to the same operating mode, but their operating wavelengths are slightly different due to errors, they do not fall within the scope of different operating wavelengths described in this embodiment, but within the scope of the same operating wavelength. For example, if one laser has an operating wavelength of 1270 nm and another laser has an operating wavelength of 1271 nm, and both lasers operate in the 10GPON operating mode, then the difference in the operating wavelengths of these two lasers is caused by errors and does not fall within the scope of different operating wavelengths described in this embodiment, but within the scope of the same operating wavelength.

[0082] As an example, the first operating mode may be the 10GPON operating mode, and the second operating mode may be the 50GPON operating mode (of course, it may also be that the first operating mode is the GPON operating mode and the second operating mode is the 10GPON operating mode). Subsequently, in the scenario introduction, the first operating mode may be the 10GPON operating mode and the second operating mode may be the 50GPON operating mode for introduction.

[0083] To simplify the optical system, multiple lasers share a laser driving unit 2. For example, both poles of multiple lasers are connected to the same laser driving unit 2. The laser driving unit 2 is used to apply a DC voltage across the two poles of the laser to stimulate the laser to emit light. Therefore, the laser driving unit 2 can also be referred to as a direct current driver.

[0084] Generally, the optical system operates in one operating mode at the same time point. Therefore, as shown in Figure 2 , a switch is integrated inside the laser driving unit 2. The switch can control the lasers corresponding to the operating mode indicated by the mode selection signal to operate based on the received mode selection signal, and control the remaining lasers not to operate. Here, a laser operating means the laser emits laser light, and a laser not operating means the laser does not emit laser light.

[0085] Among them, the switch (such as the first switch M1 described later) inside the laser driving unit 2 controls some lasers to operate and some lasers not to operate based on the mode selection signal, which is implemented by hardware and does not involve software program improvement.

[0086] For example, the laser driving unit 2 receives a mode selection signal sent by the media access control (MAC) chip of the ONU or outside the ONU. The mode selection signal is used to indicate the current operating mode of the optical system. Then, the laser driving unit 2 makes the corresponding lasers operate based on the operating mode indicated by the mode selection signal.

[0087] Among them, the mode selection signal can be a level signal. For example, a high level represents the first working mode, and a low level represents the second working mode. The working mode in which the optical system is currently located is the user's choice. For example, when the user installs the network and requests to use 10GPON network communication, then the optical system is currently in the first working mode. Later, when the user wants to upgrade to 50GPON network communication, the operator only needs to update the current working mode of the optical system to the second working mode, without replacing the ONU.

[0088] In this way, the MAC chip or the external device sends a mode selection signal (i.e., a high level) to the laser driving unit. After the laser driving unit 2 receives the mode selection signal, it controls the laser corresponding to the working mode indicated by the mode selection signal to work.

[0089] Furthermore, multiple lasers also share a modulation unit 3. For example, both poles of multiple lasers are connected to the same modulation unit 3. The modulation unit 3 is used to apply a high-speed alternating current signal to both poles of multiple lasers to modulate the light emitted by the working laser into an optical signal carrying the information to be transmitted. Therefore, the modulation unit 3 can also be called an alternating current driver.

[0090] Similarly, if the optical system is an optical transceiver system, as shown in Figure 2 it will also include a detector 4 and a transimpedance amplifier 5. Usually, the working mode of the optical system and the working wavelength of the detector (i.e., the wavelength of the light received by the detector) are in one-to-one correspondence. For example, in the 10GPON working mode, the working wavelength of the detector is 1577nm, and in the 50GPON working mode, the working wavelength of the detector is 1342nm.

[0091] Therefore, in a multimode optical system with multiple working modes, the number of detectors 4 is multiple, and at least two of the multiple detectors have different working wavelengths. In this embodiment, for the convenience of introduction, a dual-mode optical system is taken as an example. The optical system includes the first working mode and the second working mode described above. Then, the number of detectors is two, which are respectively denoted as the first detector 41 and the second detector 42, and the working wavelengths of the first detector 41 and the second detector 42 are different. For example, the first detector 41 works in the first working mode, and the second detector 42 works in the second working mode.

[0092] It should be noted that the different operating wavelengths of the two detectors described in this embodiment refer to the different operating modes to which the two detectors belong, and the resulting different operating wavelengths are not due to errors. Similarly, the same operating wavelength of the two detectors described in this embodiment means that the two detectors belong to the same operating mode.

[0093] To simplify the optical system, multiple detectors share a transimpedance amplifier. For example, the electrical signals output by multiple detectors are all transmitted to the same transimpedance amplifier for electrical signal amplification. Usually, the optical system operates in one operating mode at the same time point. Therefore, referring to Figure 2 as shown, the transimpedance amplifier 5 integrates a switch inside. The switch can receive a mode selection signal and control the detector corresponding to the operating mode indicated by the mode selection signal to be electrically connected to the output end of the transimpedance amplifier 5, so that the transimpedance amplifier 5 amplifies the electrical signal of the detector corresponding to the operating mode indicated by the mode selection signal and outputs the amplified electrical signal to the next component (such as a limiting amplifier).

[0094] As can be seen from the above, in the multimode optical system of this embodiment, the lasers in different operating modes share a laser driving unit 2 and a modulation unit 3, and the detectors in different operating modes share a transimpedance amplifier, which can reduce the number of laser driving units 2, the number of modulation units 3, and the number of transimpedance amplifiers, thereby simplifying the circuit inside the optical system.

[0095] In one example, referring to Figure 2 as shown, the laser driving unit 2 is used to input a DC voltage to the laser to excite the laser to emit light, and the modulation unit 3 is used to input a high-speed AC voltage to the laser to generate an optical signal carrying information. Therefore, both the laser driving unit 2 and the modulation unit 3 input a driving voltage to the laser, so the two can be integrated into a driving chip, which can be denoted as an optical physical (PHY) chip.

[0096] As described above, usually the optical system operates in one operating mode at the same time point. Therefore, the lasers in different operating modes can share the same optical path. The optical system also includes a multiplexer. Two lasers with different operating wavelengths are respectively located on the demultiplexed optical paths of the multiplexer, and the multiplexed optical path of the multiplexer corresponds to the optical port. For example, referring to Figure 2 as shown, the first laser 11 belonging to the first operating mode and the second laser 12 belonging to the second operating mode share the same optical port. The detectors in different operating modes can also share the same optical path. Therefore, two detectors with different operating wavelengths are respectively located on the demultiplexed optical paths of the multiplexer, and the multiplexed optical path of the multiplexer corresponds to the optical port. For example, referring to Figure 2As shown, the first detector 41 belonging to the first working mode and the second detector 42 belonging to the second working mode share a single optical port.

[0097] In one example, the transmitter optical sub-assembly (TOSA) and the receiver optical sub-assembly (ROSA) in the optical system can be integrated together and called a bi-directional optical sub-assembly (BOSA). Then, referring to Figure 2 As shown, the laser and the detector in the optical system use the same optical fiber to transmit optical signals. Then, wavelength division multiplexing technology needs to be adopted to transmit optical signals. Therefore, the transmission optical path of the laser and the reception optical path of the detector are respectively located on the demultiplexed optical paths of the multiplexer, and the multiplexed optical path of the multiplexer corresponds to the optical port of the optical system. For example, continuing to refer to Figure 2 As shown, the first laser 11 and the first detector 41 belonging to the first working mode belong to the BOSA in the first working mode and share a single optical port. The second laser 12 and the second detector 42 belonging to the second working mode belong to the BOSA in the second working mode and share a single optical port.

[0098] For the above BOSA in different working modes, sharing a single optical port and transmitting optical signals through the same optical port, when the optical system updates the working mode, there is no need to plug and unplug the optical fiber. Thus, without the need to plug and unplug the optical fiber to replace the optical port, the multi-mode switching function of the optical system can be achieved, enhancing the application flexibility of the optical network device where the optical system is located.

[0099] Next, the circuit connection relationship between the laser driving unit 2 and multiple lasers 1, the circuit connection relationship between the modulation unit 3 and multiple lasers 1, and the circuit connection relationship between the transimpedance amplifier and multiple detectors 4 will be introduced.

[0100] For ease of explanation, in the following introduction, two working modes, two lasers, and two detectors are taken as examples, and it is assumed that the first laser 11 and the first detector 41 work in the first working mode, and the second laser 12 and the second detector 42 work in the second working mode.

[0101] As Figure 3 shown, it is a schematic diagram of the electrical connection between the laser driving unit 2 and the modulation unit 3 and two lasers respectively. Referring to Figure 3 As shown, the laser driving unit 2 includes a first terminal 21, a second terminal 22, and a first switch M1. The first switch M1 is specifically a multi-pole multi-throw electronic switch with multiple input terminals and multiple output terminals. Referring to Figure 3As shown, multiple input terminals of the first switch M1 are electrically connected to multiple first connection terminals 21 one by one, multiple output terminals of the first switch M1 are electrically connected to the first poles of multiple lasers one by one, and the second poles of the multiple lasers are all electrically connected to the second connection terminal.

[0102] Among them, the second poles of the multiple lasers are all electrically connected to the second connection terminal 22. For example, referring to Figure 3 As shown, after the second poles of the multiple lasers are electrically connected in sequence, they are then electrically connected to the second connection terminal 22. Another example is that the second poles of the multiple lasers are respectively electrically connected to the second connection terminal 22.

[0103] Among them, multiple first connection terminals 21 are all used to input DC voltage, and the second connection terminal 22 is used to output DC voltage. Referring to Figure 3 As shown, among the multiple first connection terminals 21, there are a target connection terminal 211 and non-target connection terminals 212. Among them, any laser electrically connected to the target connection terminal 211 can work, and any laser electrically connected to the non-target connection terminals 212 cannot work.

[0104] Among them, the first switch is used to receive a mode selection signal, and based on the working mode indicated by the mode selection signal, control the first pole of the corresponding laser to be electrically connected to the target connection terminal, and control the first poles of other lasers to be electrically connected to the non-target connection terminals. Among them, the corresponding laser is the laser that works in the working mode indicated by the mode selection signal, and other lasers are the lasers that do not work in the working mode indicated by the mode selection signal.

[0105] Then, in this way, the laser driving unit 2 can control the corresponding lasers to work based on the working mode indicated by the mode selection signal, and control the remaining lasers not to work, so that a single laser driving unit 2 can control the lasers in multiple working modes to work.

[0106] Continue to refer to Figure 3 As shown, the first poles of the multiple lasers are also all electrically connected to a connection terminal of the modulation unit 3, and the second poles of the multiple lasers are also all electrically connected to another connection terminal of the modulation unit 3.

[0107] Taking Figure 3 as an example, the first connection terminal 21 includes a target connection terminal 211 and a non-target connection terminal 212. The target connection terminal 211 is electrically connected to the input terminal a1 of the first switch M1, the non-target connection terminal 212 is electrically connected to the input terminal b1 of the first switch M1, the first pole of the first laser 11 is electrically connected to the output terminal d1 of the first switch M1, and the first pole of the second laser 12 is electrically connected to the output terminal c1 of the first switch M1.

[0108] Still taking the mode selection signal as a level signal, where a high level represents the first operating mode and a low level represents the second operating mode. For example, the first laser 11 operates in the first operating mode and the second laser 12 operates in the second operating mode.

[0109] If the current operating mode of the optical system is the first operating mode, the mode selection signal received by the first switch M1 is a high level. When the first switch M1 receives a high level, it controls its input terminal a1 to be electrically connected to the output terminal d1, and the input terminal b1 to be electrically connected to the output terminal c1. At this time, the first laser 11 is electrically connected to the target terminal 211, the first laser 11 emits light, the second laser 12 is electrically connected to the non-target terminal 212, and the second laser 12 does not emit light.

[0110] Continue to refer to Figure 3 As shown, the first poles of the first laser 11 and the second laser 12 are both electrically connected to a terminal of the modulation unit 3, and the second poles of the first laser 11 and the second laser 12 are both electrically connected to another terminal of the modulation unit 3.

[0111] Therefore, at this time, although the modulation unit 3 can apply a high-speed AC voltage to the two lasers as an AC driver, the voltage value of the high-speed AC voltage used to modulate the optical signal is not high, and the voltage across the second laser 12 is not sufficient to make it forward-biased, and even reverse-biased. Therefore, the impedance of the second laser 12 is very large and it still does not emit light. However, since the first laser 11 is electrically connected to the target terminal 211 and can emit light, the voltage applied across the first laser 11 is greater than the turn-on voltage (V0). Therefore, the modulation unit 3 can only modulate the transmitted information onto the laser emitted by the first laser 11. Thus, the modulation unit is a single-channel driving multiple lasers.

[0112] If the current operating mode of the optical system is the second operating mode, the mode selection signal received by the first switch M1 is a low level. When the first switch M1 receives a low level, it controls its input terminal a1 to be electrically connected to the output terminal c1, and the input terminal b1 to be electrically connected to the output terminal d1. At this time, the second laser 12 is electrically connected to the target terminal 211, the second laser 12 emits light, the first laser 11 is electrically connected to the non-target terminal 212, and the first laser 11 does not emit light.

[0113] At this time, although the modulation unit 3 acts as an AC driver and can apply a high-speed AC voltage across the two lasers, the voltage value of the high-speed AC voltage used to modulate the optical signal is not high. The voltage across the first laser 11 is not sufficient to forward bias it, and may even reverse bias it. Therefore, the impedance of the first laser 11 is very large and it still does not emit light. Since the second laser 12 is electrically connected to the target terminal 211, the voltage applied across the second laser 12 is greater than the turn-on voltage (V0), so it can emit light. Therefore, the modulation unit 3 can only modulate the transmitted information onto the laser emitted by the second laser 12.

[0114] The reason why the laser connected to the target terminal 211 can emit light while the laser connected to the non-target terminal 212 cannot is that the voltage across the laser connected to the target terminal 211 is greater than the turn-on voltage of this laser. Therefore, it can emit light, while the voltage across the laser connected to the non-target terminal 212 is less than the turn-on voltage of this laser. Therefore, it cannot emit light. For the convenience of introduction, the turn-on voltages of all lasers are considered to be equal, all being V0. Of course, the turn-on voltages of different lasers can also be unequal.

[0115] In order to prevent the laser connected to the non-target terminal 212 from emitting light, it is necessary to satisfy V2 - V3 < V0, where V2 is the voltage value input to the input terminal b1 of the first switch M1, V3 is the voltage value output from the second terminal 22, and V0 is the turn-on voltage of the laser.

[0116] In order to enable the laser connected to the target terminal 211 to emit light, it is necessary to satisfy V1 - V3 ≥ V0, where V1 is the voltage value input to the input terminal a1 of the first switch M1. Among them, V1 > V2.

[0117] To satisfy V1 > V2, one implementation is that the voltage input from the target terminal 211 to the input terminal a1 of the first switch M1 is V1, and the voltage input from the non-target terminal 212 to the input terminal b1 of the first switch M1 is V2, and V1 is greater than V2. That is, the target terminal 211 inputs a relatively high voltage to the input terminal a1 of the first switch M1, while the non-target terminal 212 inputs a relatively low voltage to the input terminal b1 of the first switch M1. Thus, V1 - V3 ≥ V0 and V2 - V3 < V0.

[0118] Another implementation is that the voltage input by the target terminal 211 to the input terminal a1 of the first switch M1 is equal to the voltage input by the non-target terminal 212 to the input terminal b1 of the first switch M1. However, there is a pull-up resistor between the target terminal 211 and the input terminal a1 of the first switch M1, and the pull-up resistor is connected to a power supply. Then, the voltage input to the input terminal a1 of the first switch M1 comes from the voltage provided by the target terminal 211 on the one hand and the voltage provided by the power supply connected to the pull-up resistor on the other hand. Therefore, the voltage V1 input to the input terminal a1 of the first switch M1 can be made relatively large. While the voltage input to the input terminal b1 of the first switch M1 only comes from the voltage provided by the non-target terminal 212, so the voltage V2 input to the input terminal b1 of the first switch M1 is relatively small, thus satisfying V1 > V2. Furthermore, V1 - V3 ≥ V0, V2 - V3 < V0.

[0119] As described above, the first poles of multiple lasers are all electrically connected to the modulation unit 3, and the second poles of multiple lasers are all electrically connected to the modulation unit 3. One connection method can be that the first poles of multiple lasers are respectively electrically connected to the modulation unit 3 through a line, and the second poles of multiple lasers are respectively electrically connected to the modulation unit 3 through a line. That is to say, the first poles of multiple lasers are respectively electrically connected to the modulation unit 3, the second poles of multiple lasers are respectively electrically connected to the modulation unit 3, the first poles of multiple lasers are not connected to each other, and the second poles of multiple lasers are not connected to each other.

[0120] In another example, to reduce the circuit layout, refer to Figure 3 As shown, the first poles of multiple lasers can be connected in sequence and then electrically connected to the modulation unit 3, and the second poles of multiple lasers can be connected in sequence and then electrically connected to the modulation unit 3. Since the second poles of multiple lasers are connected in sequence and are also connected to the second terminal 22, then, after the second poles of multiple lasers are connected in sequence, they can be both electrically connected to the second terminal 22 and electrically connected to the modulation unit 3. Therefore, refer to Figure 3 As shown, after the second pole of the first laser 11 and the second pole of the second laser 12 are electrically connected, they are respectively connected to the second terminal 22 and the modulation unit 3.

[0121] However, after the first poles of multiple lasers are connected in sequence, all the lasers will be electrically connected to the target terminal and also to the non-target terminal. For this reason, refer to Figure 3 As shown, a capacitor is arranged on the electrical connection line between the first poles of two connected lasers. Based on the characteristic of the capacitor blocking direct current and passing alternating current, thus, in the alternating current circuit, all the lasers are connected in parallel to the modulation unit 3, while in the direct current circuit, all the lasers are isolated from each other.

[0122] For example, continue to refer toFigure 3 As shown, after the first poles of the first laser 11 and the second laser 12 are connected, they are electrically connected to one terminal of the modulation unit 3. A capacitor is arranged on the line between the first poles of the first laser 11 and the second laser 12. After the second poles of the first laser 11 and the second laser 12 are connected in sequence, they are connected to the other terminal of the modulation unit 3.

[0123] In order to prevent the AC signal output by the modulation unit 3 from being serially connected into the DC circuit and flowing out through the first terminal 21 or the second terminal 22 in the DC circuit, an inductor can be arranged on the DC circuit. Based on the characteristics of the inductor of passing DC and blocking AC, passing low-frequency and blocking high-frequency, the high-speed AC signal can be blocked from flowing into the DC circuit.

[0124] For example, referring to Figure 3 As shown, for each laser: at least one inductor is arranged on the line between the electrically connected position of the first pole of the laser and the modulation unit 3 and the output terminal of the first switch M1 that is electrically connected to the first pole of the laser; at least one inductor is arranged on the line between the electrically connected position of the second pole of the laser and the modulation unit 3 and the second terminal 22. For example, referring to Figure 3 In [reference], at least one inductor is arranged on the circuit between position A and the output terminal d1 of the first switch M1, at least one inductor is arranged on the circuit between position B and the output terminal c1 of the first switch M1, and at least one inductor is arranged on the circuit between position C and the second terminal 22.

[0125] In this way, based on the characteristics of the inductor of passing DC and blocking AC, passing low-frequency and blocking high-frequency, the high-speed AC signal output by the modulation unit 3 can be blocked from flowing into the DC circuit.

[0126] Among them, some components can also be arranged on the electrically connected line between the first pole of each laser and the modulation unit 3, such as one or more of a resistor, an inductor, and a capacitor. Some components can also be arranged on the electrically connected line between the second pole of each laser and the modulation unit 3, such as one or more of a resistor, an inductor, and a capacitor. This embodiment does not limit this, as long as it ensures that the modulation unit 3 can input a high-speed AC signal to the laser.

[0127] Among them, Figure 3 the multi-throw first switch M1 in [reference] can also be replaced by a single-throw multi-throw switch. If the first switch M1 is a single-throw multi-throw switch, the number of the first terminals 21 is one, the number of the input terminals of the first switch M1 is one, and the number of the output terminals is equal to the number of lasers.

[0128] In one example, Figure 3The first pole of the laser shown is the anode, and the second pole of the laser is the cathode. The anodes of multiple lasers are electrically connected to the multiple output terminals of the first switch M1 one by one. The multiple input terminals of the first switch M1 are electrically connected to the multiple first connection terminals 21 one by one. The cathodes of the multiple lasers are connected and then connected to the second connection terminal 22. Among them, each first connection terminal 21 is used to input voltage, and the second connection terminal 22 is used to output voltage. This wiring method is called the common cathode wiring method of the laser.

[0129] In another example, vice versa, the first pole of the laser is the cathode, and the second pole of the laser is the anode. The cathodes of multiple lasers are electrically connected to the multiple output terminals of the first switch M1 one by one. The multiple input terminals of the first switch M1 are electrically connected to the multiple first connection terminals 21 one by one. The anodes of the multiple lasers are connected and then connected to the second connection terminal 22. Among them, each first connection terminal 21 is used to output voltage, and the second connection terminal 22 is used to input voltage. This wiring method belongs to the common anode wiring method of the laser.

[0130] In the common anode wiring of multiple lasers, in order to make the lasers electrically connected to the target connection terminal work, it is necessary to satisfy that the voltage output from the target connection terminal is the lowest. Then, a pull-down resistor can be arranged on the line between the target connection terminal 211 and the input terminal a1 of the first switch M1. The pull-down resistor can be grounded to pull down the voltage at the input terminal a1 of the first switch M1. The lower the voltage at this point, the greater the voltage applied across the connected lasers.

[0131] In another example, in the implementation where the second poles of multiple lasers are all electrically connected to the second connection terminal, it can also be that the second poles of multiple lasers are respectively electrically connected to the second connection terminal. Among them, this embodiment does not limit the implementation method of electrically connecting the second poles of multiple lasers to the second connection terminal. In the drawings, it is schematically shown that the second poles of multiple lasers are connected in sequence and then connected to the second connection terminal.

[0132] In one example, in order to enable the lasers corresponding to the current working mode to be quickly turned on and quickly turned off to reduce the delay of signal transmission, correspondingly, as Figure 4 shown, it is another electrical connection schematic diagram of the laser driving unit 2 and multiple lasers.

[0133] Refer to Figure 4 shown, the laser driving unit further includes a third connection terminal 23 and a second switch M2. The second switch M2 is a single-pole multi-throw switch, including one input terminal and multiple output terminals. The input terminal of the second switch M2 is electrically connected to the third connection terminal 23. The multiple output terminals of the second switch M2 are electrically connected to the first poles of multiple lasers one by one. For example, each output terminal of the second switch M2 is electrically connected to the line between the first pole of a laser and an output terminal of the first switch M1.

[0134] Taking Figure 4 as an example, one input terminal a2 of the second switch M2 is electrically connected to the third terminal 23, and the output terminal c2 of the second switch M2 is electrically connected to the line between the first pole of the first laser 11 and the output terminal d1 of the first switch M1. The output terminal b2 of the second switch M2 is electrically connected to the line between the first pole of the second laser 12 and the output terminal c1 of the first switch M1.

[0135] Among them, the second switch M2 is used to receive a mode selection signal and control the first pole of the corresponding laser to be electrically connected to the third terminal 23 based on the working mode indicated by the mode selection signal.

[0136] Among them, the second switch M2 controls the first pole of a certain laser to be electrically connected to the third terminal 23 based on the mode selection signal, which is achieved through hardware improvement and does not involve software program improvement.

[0137] In the case where the optical system emits an optical signal, referring to Figure 5 as shown, both the target terminal 211 and the third terminal 23 are used to input DC voltage, and the second terminal 22 is used to output DC voltage. In the case where the optical system does not emit an optical signal, referring to Figure 4 as shown, the target terminal 211 is used to input DC voltage, while the third terminal 23 is used to output DC voltage.

[0138] Still taking the mode selection signal as a level signal, where a high level represents the first working mode and a low level represents the second working mode as an example.

[0139] If the working mode of the optical system at present is the first working mode, then the mode selection signals received by the first switch M1 and the second switch M2 are both high levels. When the first switch M1 receives a high level, it controls its input terminal a1 to be electrically connected to the output terminal d1, and the input terminal b1 to be electrically connected to the output terminal c1. At the same time, the second switch M2 also receives a high level and controls its input terminal a2 to be electrically connected to the output terminal c2.

[0140] In the case where the optical system does not emit an optical signal, referring to Figure 4 as shown, the first terminal 21 is used to input DC voltage, and the third terminal 23 is used to output voltage. Then, the DC voltage input from the target terminal 211 is directly output via the third terminal 23 without passing through the laser electrically connected to the target terminal 211, so this laser does not work.

[0141] In the case where the optical system emits an optical signal, referring to Figure 5As shown, both the first terminal 21 and the third terminal 23 are used to input DC voltage, while the second terminal 22 is used to output DC voltage. Then, the DC voltage input from the target terminal 211 and the DC voltage input from the third terminal 23 are both applied to the laser electrically connected to the target terminal 211, prompting the laser to operate.

[0142] Reference Figure 4 and Figure 5 As shown, when the laser is not required to emit light, the first switch M1 and the second switch M2 are also in the closed state, and there is also current flowing through the circuit. When the laser is required to emit light, since there is always current in the circuit where the first switch M1 is located, the current can be quickly delivered to the laser connected to the target terminal 211, enabling the laser to be quickly turned on to emit light. Conversely, the laser can also be quickly turned off.

[0143] Figure 4 and Figure 5 That is, the current working mode of the optical system is the first working mode, which is the working schematic diagram of the first laser 11. Therefore, the first switch M1 controls the input terminal a1 to be electrically connected to the output terminal d1, and the input terminal b1 to be electrically connected to the output terminal c1, enabling the first laser 11 to operate. The second switch M2 controls the input terminal a2 to be electrically connected to the output terminal c2. If the current working mode of the optical system is the second working mode, the mode selection signals received by the first switch M1 and the second switch M2 are both low levels. Then, the first switch M1 controls the input terminal a1 to be electrically connected to the output terminal c1, and the input terminal b1 and the output terminal d1 to be electrically connected, enabling the second laser 12 to operate. The second switch M2 controls the input terminal a2 to be electrically connected to the output terminal b2.

[0144] The above are the circuit characteristics between the laser driving unit 2, the modulation unit 3 and multiple lasers. Next, the circuit characteristics between the transimpedance amplifier 5 and multiple detectors 4 will be introduced.

[0145] As Figure 6 shown, it is a schematic diagram of multiple detectors electrically connected to a single transimpedance amplifier 5. Reference Figure 6 As shown, the transimpedance amplifier 5 includes an output terminal, multiple input terminals and a third switch M3. The multiple input terminals of the transimpedance amplifier 5 are electrically connected to the multiple detectors 4 one by one. The third switch M3 includes multiple input terminals and one output terminal. The multiple input terminals of the transimpedance amplifier 5 are also electrically connected to the multiple input terminals of the third switch M3 one by one. The output terminal of the third switch M3 is electrically connected to the output terminal of the transimpedance amplifier 5.

[0146] Among them, the third switch M3 is used to receive a mode selection signal, and based on the operating mode indicated by the mode selection signal, control the corresponding detector, which is electrically connected to the output end of the transimpedance amplifier 5, so that the transimpedance amplifier 5 amplifies the electrical signals of the detector corresponding to the operating mode indicated by the mode selection signal, and outputs them to the next component (such as a limiting amplifier or a digital signal processor).

[0147] Among them, the third switch controls the corresponding detector to be electrically connected to the output end of the transimpedance amplifier 5 based on the mode selection signal, which is achieved through hardware improvement and does not involve software program improvement.

[0148] In one example, the receiving side of the optical system may include a limiting amplifier 6, then the output end of the transimpedance amplifier 5 is electrically connected to the limiting amplifier 6. The optical system may also include a digital signal processor (DSP), then the output end of the limiting amplifier 6 is electrically connected to the DSP, and the output end of the DSP is electrically connected to the MAC chip.

[0149] In other examples, the receiving side of the optical system may only include a limiting amplifier 6, then the output end of the transimpedance amplifier 5 is electrically connected to the limiting amplifier 6, and the output end of the limiting amplifier 6 is electrically connected to the MAC chip.

[0150] In other examples, the receiving side of the optical system may also only include a digital signal processor and not include a limiting amplifier 6, then the output end of the transimpedance amplifier 5 is electrically connected to the digital signal processor, and the output end of the digital signal processor is electrically connected to the MAC chip.

[0151] Among them, this embodiment does not limit which components the transimpedance amplifier 5 includes subsequently, and the limiting amplifier 6 may be included in the drawings as an example.

[0152] Take Figure 6 as an example, the first detector 41 is electrically connected to the input end a3 of the third switch M3 through an input end of the transimpedance amplifier 5, and the second detector 42 is electrically connected to the input end b3 of the third switch M3 through another input end of the transimpedance amplifier 5.

[0153] Still take the mode selection signal as a level signal, where a high level represents the first operating mode and a low level represents the second operating mode. The first detector 41 operates in the first operating mode and the second detector 42 operates in the second operating mode as an example.

[0154] If the current operating mode of the optical system is the first operating mode, the mode selection signal received by the third switch M3 is at a high level. When the third switch M3 receives a high level, it controls its output terminal c3 to be electrically connected to the input terminal a3. At this time, the first detector 41 is electrically connected to the output terminal of the transimpedance amplifier 5. The transimpedance amplifier 5 amplifies the electrical signal converted by the first detector 41 and outputs it to the limiting amplifier 6 for further processing.

[0155] If the current operating mode of the optical system is the second operating mode, the mode selection signal received by the third switch M3 is at a low level. When the third switch M3 receives a low level, it controls its output terminal c3 to be electrically connected to the input terminal b3. At this time, the second detector 42 is electrically connected to the output terminal of the transimpedance amplifier 5. The transimpedance amplifier 5 amplifies the electrical signal converted by the second detector 42 and outputs it to the limiting amplifier 6 for further processing.

[0156] Continue to refer to Figure 6 As shown, the optical signals entering the optical port of the optical system include an optical signal with a first wavelength (the first wavelength is the operating wavelength of the first detector 41) and an optical signal with a second wavelength (the second wavelength is the operating wavelength of the second detector 42). After the two-wavelength optical signals enter the multiplexer and are demultiplexed by the multiplexer 7, the optical signal with the first wavelength enters the first detector 41 for photoelectric conversion, and the optical signal with the second wavelength enters the second detector 42 for photoelectric conversion. Only the detector electrically connected to the output terminal of the transimpedance amplifier 5 can output the converted electrical signal to the limiting amplifier 6.

[0157] Refer to Figure 6 As shown, multiple detectors use the same transimpedance amplifier 5 for amplification processing, which can reduce the number of transimpedance amplifiers.

[0158] In one example, the transimpedance amplifier 5 not only integrates the third switch M3 but also an amplifier. By integrating the third switch M3 into the transimpedance amplifier 5, the electrical connection path between the amplifier and the third switch M3 in the transimpedance amplifier is short, and single-ended routing can be used to achieve electrical connection to reduce transmission delay.

[0159] Based on the above, taking the example of the MAC chip sending a mode selection signal to the laser driving unit 2 and the transimpedance amplifier 5, refer to Figure 7 As shown, the laser driving unit 2, the modulation unit 3, and the transimpedance amplifier 5 are all electrically connected to the MAC chip.

[0160] Refer to Figure 7As shown, if the current operating mode of the optical system is the first operating mode, the mode selection signals received by the first switch M1, the second switch M2, and the third switch M3 are high level. The first switch M1 controls the first laser 11 to be electrically connected to the target terminal 211 and controls the second laser 12 to be electrically connected to the non-target terminal 212. The second switch M2 controls the first laser 11 to be electrically connected to the third terminal 23. The third switch M3 controls the first detector 41 to be electrically connected to the output terminal of the transimpedance amplifier 5.

[0161] Reference Figure 7 As shown, if the current operating mode of the optical system is the second operating mode, the mode selection signals received by the first switch M1, the second switch M2, and the third switch M3 are low level. The first switch M1 controls the second laser 12 to be electrically connected to the target terminal 211 and controls the first laser 11 to be electrically connected to the non-target terminal 212. The second switch M2 controls the second laser 12 to be electrically connected to the third terminal 23. The third switch M3 controls the second detector 42 to be electrically connected to the output terminal of the transimpedance amplifier 5.

[0162] Among them, the above is introduced by taking a dual-mode optical system as an example. For a three-mode or even more-mode optical system, the principle is similar to that of the dual-mode optical system. It only needs to increase the number of lasers, increase the number of detectors, and increase the channels of the first switch M1, the second switch M2, and the third switch M3. The above dual-mode optical system can be referred to.

[0163] In one example, the optical system can also be applied to a solution with a main optical port and a standby optical port, such as Figure 8 As shown, both the OLT and the first ODN and the second ODN are electrically connected by optical fibers. For each ONU, it is electrically connected to the first ODN and the second ODN by optical fibers respectively. For the two optical fibers connected to the ONU, one optical fiber is used as the main optical fiber and is inserted into the main optical port of the ONU, and the other optical fiber is used as the standby optical fiber and is inserted into the standby optical port of the ONU ( Figure 8 In, the optical fiber shown by the solid line can be recorded as the main optical fiber, and the optical fiber shown by the dashed line can be recorded as the standby optical fiber). In this way, even when there is a link failure in the main optical fiber, communication can still be carried out between the ONU and the OLT through the standby optical fiber.

[0164] Then, in the scenario as shown in Figure 8 Reference Figure 9Partial schematic diagram of the optical system shown. The number of lasers is at least four. Taking four as an example, they are respectively denoted as the first laser 11, the second laser 12, the third laser 13, and the fourth laser 14. The operating wavelengths of the first laser 11 and the third laser 13 are the same, and they both operate in the first operating mode. The first laser 11 communicates through the main optical port, and the third laser 13 communicates through the standby optical port. The operating wavelengths of the second laser 12 and the fourth laser 14 are the same, and they both operate in the second operating mode. The second laser 12 communicates through the main optical port, and the fourth laser 14 communicates through the standby optical port.

[0165] Similarly, the number of detectors is also four, which are respectively denoted as the first detector 41, the second detector 42, the third detector 43, and the fourth detector 44. The operating wavelengths of the first detector 41 and the third detector 43 are the same, and they both operate in the first operating mode. The first detector 41 communicates through the main optical port, and the third detector 43 communicates through the standby optical port. The operating wavelengths of the second detector 42 and the fourth detector 44 are the same, and they both operate in the second operating mode. The second detector 42 communicates through the main optical port, and the fourth detector 44 communicates through the standby optical port.

[0166] Since the lasers and detectors in the same operating mode can transmit optical signals through one optical port, therefore, continue to refer to Figure 9 As shown, the first laser 11 and the first detector 41 that operate in the first operating mode, and the second laser 12 and the second detector 42 that operate in the second operating mode, transmit optical signals through the same main optical port. Then, the first laser 11, the first detector 41, the second laser 12, and the second detector 42 are respectively on the demultiplexing optical paths of the first multiplexer 71, and the multiplexing optical path of the first multiplexer 71 corresponds to the main optical port.

[0167] Similarly, the third laser 13 and the third detector 43 that operate in the first operating mode, and the fourth laser 14 and the fourth detector 44 that operate in the second operating mode, transmit optical signals through the same standby optical port. Then, the third laser 13, the third detector 43, the fourth laser 14, and the fourth detector 44 are respectively on the demultiplexing optical paths of the second multiplexer 72, and the multiplexing optical path of the second multiplexer 72 corresponds to the standby optical port.

[0168] Since the optical system transmits information in a working mode through a single optical fiber at a certain point in time, the laser driving unit 2 selects one of the four lasers to operate, and the transimpedance amplifier 5 amplifies the electrical signal output from one of the four detectors. In this case, the laser driving unit 2 needs to determine which laser corresponding to which optical port operates in which working mode based not only on the mode selection signal but also on the primary / backup selection signal. The transimpedance amplifier 5 needs to determine which electrical signal output from the detector corresponding to which optical port in which working mode is to be amplified based not only on the mode selection signal but also on the primary / backup selection signal.

[0169] Reference Figure 10 As shown, the number of the first connection terminals 21 is four, including one target connection terminal and three non-target connection terminals. The first switch M1 includes four input terminals and four output terminals. The four first connection terminals 21 are electrically connected to the four input terminals of the first switch M1 one by one. The first poles of the four lasers are electrically connected to the four output terminals of the first switch M1 one by one. The second switch M2 includes one input terminal and four output terminals, and the four output terminals of the second switch M2 are electrically connected to the first poles of the four lasers one by one. For example, each input terminal of the second switch M2 is electrically connected to the wire between the first pole of a laser and the output terminal of the first switch M1. The third switch M3 includes one output terminal and four input terminals, and the four input terminals of the third switch M3 are electrically connected to the output terminals of the four detectors one by one.

[0170] If the working mode indicated by the mode selection signal is the first working mode and the optical port indicated by the primary / backup selection signal is the primary optical port, the first laser 11 operates, and the other lasers do not operate. The transimpedance amplifier 5 amplifies the electrical signal converted by the first detector 41.

[0171] If the working mode indicated by the mode selection signal is the first working mode and the optical port indicated by the primary / backup selection signal is the backup optical port, the third laser 13 operates, and the other lasers do not operate. The transimpedance amplifier 5 amplifies the electrical signal converted by the third detector 43.

[0172] If the working mode indicated by the mode selection signal is the second working mode and the optical port indicated by the primary / backup selection signal is the primary optical port, the second laser 12 operates, and the transimpedance amplifier 5 amplifies the electrical signal converted by the second detector 42.

[0173] If the working mode indicated by the mode selection signal is the second working mode and the optical port indicated by the primary / backup selection signal is the backup optical port, the fourth laser 14 operates, and the transimpedance amplifier 5 amplifies the electrical signal converted by the fourth detector 44.

[0174] The features of the above-mentioned laser are introduced below. In one example, the laser can specifically be a direct modulation laser (DML), or an external modulation laser, and the external modulation laser can specifically be an Electro-absorption Modulated Laser (EML) or a Mach-Zehnder Modulator (MZ). The type of the laser is not limited in this embodiment.

[0175] As mentioned above, the number of lasers is multiple, and these multiple lasers can be multiple independent semiconductor laser chips, which are then packaged on the same circuit board to form an optical emission component.

[0176] In another example, multiple lasers can be integrated in one semiconductor laser chip. Then, the semiconductor laser chip has multiple resonant cavities, and one resonant cavity serves as one laser. As Figure 11 shown, it is a schematic diagram of two lasers integrated in one semiconductor laser chip. Refer to Figure 11 shown, the semiconductor laser chip has two resonant cavities. One of these two resonant cavities serves as the resonant cavity of the first laser, and the other serves as the resonant cavity of the second laser. Since the operating wavelengths of the first laser and the second laser are different, different gratings are etched on these two resonant cavities to achieve different emitted wavelengths.

[0177] For example, the operating wavelength of the laser corresponding to the 10GPON operating mode is 1270nm ± 10nm, and the operating wavelength of the laser corresponding to the 50GPON operating mode is 1286nm ± 2nm. These two operating wavelengths are relatively close. Therefore, the lasers corresponding to these two operating modes can be integrated in one semiconductor laser chip.

[0178] This solution of integrating multiple lasers in one semiconductor laser chip, that is, the solution of processing lasers with multiple different wavelengths on the same silicon wafer, can significantly reduce costs compared with processing semiconductor laser chips with multiple different wavelengths.

[0179] In the solution of integrating multiple lasers in one semiconductor laser chip, the multiple resonant cavities can be arranged parallel to each other as shown in Figure 11 shown, or can be arranged along the same center line (i.e., in series) as shown in Figure 12 shown.

[0180] As described above, lasers with different working wavelengths can share the same optical port of the optical system. Then, for multiple lasers with different working wavelengths, a multiplexer is still needed to deliver the optical signals emitted by the lasers with different working wavelengths to the same optical port.

[0181] In the solution where multiple lasers are integrated on the same semiconductor laser chip, the multiplexer can also be integrated on this semiconductor laser chip. Refer to Figure 13 As shown, the semiconductor laser chip integrates two lasers with different working wavelengths and a multiplexer.

[0182] In one example, whether multiple lasers are integrated on the same semiconductor laser chip or on different semiconductor laser chips, these lasers can be packaged together, that is, packaged on the same circuit board to form a multi-optical-path optical transmitter.

[0183] As Figure 14 shown, it is a schematic structural diagram of a multi-optical-path optical transmitter. Refer to Figure 14 As shown, the optical transmitter not only includes Laser 1, but also includes multiple fourth connection terminals 15, a fifth connection terminal 16, and a sixth connection terminal 17. Among them, the fourth connection terminal 15 is a DC connection terminal, the fifth connection terminal 16 is an AC connection terminal, and multiple lasers adopt a common cathode connection method, then the sixth connection terminal 17 serves as both a DC connection terminal and an AC connection terminal.

[0184] Then, refer to Figure 14 As shown, the first poles of multiple lasers 1 are electrically connected to multiple fourth connection terminals 15 one by one, and the fourth connection terminals 15 are used to be electrically connected to the laser driving unit 2. For example, multiple fourth connection terminals 15 are electrically connected to multiple output terminals of the first switch M1 of the laser driving unit 2 one by one.

[0185] The first poles of multiple lasers 1 are also all electrically connected to the fifth connection terminal 16, and the fifth connection terminal 16 is used to be electrically connected to the modulation unit 3.

[0186] The second poles of multiple lasers are all electrically connected to the sixth connection terminal 17, and the sixth connection terminal 17 is used to be electrically connected to the laser driving unit 2 and the modulation unit 3 respectively. For example, the sixth connection terminal 17 is used to be electrically connected to the second connection terminal 22 of the laser driving unit 2.

[0187] Continue to refer to Figure 14As shown, the capacitance on the connection line between the first poles of two adjacent lasers is also integrated in the optical transmitter. The inductor used to isolate the DC circuit and the AC circuit is also integrated in the optical transmitter. For example, for each laser, an inductor is arranged on the line between the electrical connection position between the first pole of the laser and the fifth terminal 16 and the fourth terminal 15 connected to the first pole of the laser. That is, referring to Figure 14 As shown, an inductor is arranged on the line between the electrical connection position E and a fourth terminal 15, and an inductor is arranged on the line between the electrical connection position F and another fourth terminal 15.

[0188] In the embodiment of the present disclosure, the lasers corresponding to different operating modes of the multi-mode optical system use the same laser driving unit to start working, and also use the same modulation unit to modulate the emitted light into an optical signal carrying information. Compared with the lasers corresponding to different operating modes that use different laser driving units to start working and different modulation units to modulate the emitted light into an optical signal, the optical system provided in this embodiment is beneficial to reducing the components in the optical system and simplifying the internal structure of the optical system.

[0189] This embodiment also provides an optical network device. The optical network device includes a MAC chip and the optical system described above. The laser driving unit and the modulation unit of the optical system are both electrically connected to the MAC chip. Among them, the optical network device can specifically be an ONU or an ONT, or can also be an optical module that can be plugged into a device.

[0190] The above are only optional embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. An optical system, characterized in that: The optical system comprises a plurality of lasers (1), a laser driving unit (2) and a modulation unit (3); At least two lasers (1) among the plurality of lasers (1) have different operating wavelengths, and each operating wavelength corresponds to an operating mode of the optical system; The plurality of lasers (1) are all electrically connected to the laser driving unit (2), the laser driving unit (2) is used to receive a mode selection signal, the mode selection signal is used to indicate the current working mode of the optical system, and the laser driving unit (2) is also used to drive the laser (1) corresponding to the working mode indicated by the mode selection signal to work; The multiple lasers (1) are also electrically connected to the modulation unit (3), and the modulation unit (3) is used to modulate the light emitted by the working lasers (1) into an optical signal carrying information.

2. The optical system according to claim 1, characterized in that The optical system further comprises a combiner (7), lasers (1) with different working wavelengths are located on the demultiplexing optical path of the combiner (7), and an optical port of the optical system is located on the combining optical path of the combiner (7).

3. The optical system according to claim 1, characterized in that The laser driving unit (2) and the modulation unit (3) are integrated in the same driving chip.

4. The optical system according to claim 1, characterized in that The laser driving unit (2) comprises a plurality of first wiring terminals (21), a second wiring terminal (22) and a first switch; The first switch has a plurality of input terminals and a plurality of output terminals, the plurality of first terminals (21) are electrically connected one by one to the plurality of input terminals of the first switch, the plurality of output terminals of the first switch are electrically connected one by one to the first poles of the plurality of lasers (1), and the second poles of the plurality of lasers (1) are all electrically connected to the second terminals (22); The plurality of first terminals (21) are all used for inputting a DC voltage, the second terminals (22) are used for outputting a DC voltage, and the plurality of first terminals (21) include a target terminal (211) and a non-target terminal (212), and the laser (1) electrically connected to the target terminal (211) can work, while the laser (1) electrically connected to the non-target terminal (212) cannot work; The first switch is used to receive a mode selection signal and, based on the working mode indicated by the mode selection signal, control the first pole of the corresponding laser (1) to be electrically connected to the target terminal (211), and control the first poles of other lasers (1) to be electrically connected to the non-target terminal (212).

5. The optical system according to claim 4, characterized in that The laser driving unit (2) further comprises a third wiring terminal (23) and a second switch; The third terminal (23) is electrically connected to the input terminal of the second switch, and the plurality of output terminals of the second switch are electrically connected one by one to the first poles of the plurality of lasers (1); The second switch is used to receive the mode selection signal and, based on the working mode indicated by the mode selection signal, control the first pole of the corresponding laser (1) to be electrically connected to the third terminal (23); When the optical system does not transmit an optical signal, the first terminal (21) is used to input a DC voltage, and the third terminal (23) is used to output a DC voltage; when the optical system transmits an optical signal, both the first terminal (21) and the third terminal (23) are used to input a DC voltage, and the second terminal (22) is used to output a DC voltage.

6. The optical system according to claim 1, characterized in that The first electrodes of the plurality of lasers (1) are connected in sequence and then connected to the modulation unit (3), and a capacitor is arranged on the connection line between the first electrodes of two lasers (1); the second electrodes of the plurality of lasers (1) are connected in sequence and then connected to the modulation unit (3); the modulation unit (3) is used to input an alternating current voltage to the plurality of lasers (1) so as to modulate the light emitted by the working lasers (1) into an optical signal carrying information.

7. The optical system according to any one of claims 1 to 6, characterized in that: The optical system further comprises a plurality of detectors (4) and a transimpedance amplifier (5); At least two detectors (4) among the plurality of detectors (4) have different operating wavelengths, and each operating wavelength corresponds to an operating mode of the optical system; The transimpedance amplifier (5) comprises an output end, a plurality of input ends and a third switch, the output end of the third switch being electrically connected to the output end of the transimpedance amplifier (5), the plurality of input ends of the third switch being electrically connected one-to-one to the plurality of input ends of the transimpedance amplifier (5), and the plurality of input ends of the transimpedance amplifier (5) being electrically connected one-to-one to the plurality of detectors (4); The third switch is used to receive the mode selection signal and, based on the working mode indicated by the mode selection signal, control the corresponding detector (4) and electrically connect to the output end of the transimpedance amplifier (5), so that the transimpedance amplifier (5) amplifies and outputs the electrical signal of the detector (4) corresponding to the working mode indicated by the mode selection signal.

8. A light transmitter, characterized in that: The optical transmitter comprises a plurality of lasers (1), a plurality of fourth terminals (15), a fifth terminal (16) and a sixth terminal (17); The first poles of the plurality of lasers (1) are electrically connected to the plurality of fourth wiring terminals (15) one by one, and the plurality of fourth wiring terminals (15) are used to be electrically connected to the laser driving unit (2); The first electrodes of the plurality of lasers (1) are also electrically connected to the fifth terminal (16), and the fifth terminal (16) is used to be electrically connected to the modulation unit (3); The second poles of the plurality of lasers (1) are all electrically connected to the sixth terminal (17), and the sixth terminal (17) is used to be electrically connected to the laser driving unit (2) and the modulation unit (3) respectively.

9. The optical transmitter according to claim 8, characterized in that After the first poles of the lasers (1) are connected in sequence, they are electrically connected to the fifth terminal (16), and a capacitor is arranged on the connection line between the first poles of the two connected lasers (1).

10. The optical transmitter according to claim 8, characterized in that An inductor is arranged on a line between the first pole of the laser (1) and the fourth terminal (15), and at a position close to the fourth terminal (15).

11. An optical network device, characterized in that: The optical network device comprises a media access control chip and the optical system according to any one of claims 1 to 7, wherein the laser driving unit and the modulation unit of the optical system are both electrically connected to the media access control chip.

Images