WO2020238279A1

WO2020238279A1 - Plc chip, tosa, bosa, optical module, and optical network device

Info

Publication number: WO2020238279A1
Application number: PCT/CN2020/074280
Authority: WO
Inventors: 王衡; 锁靖; 吴徐明; 董英华; 周恩宇
Original assignee: 华为技术有限公司
Priority date: 2019-05-27
Filing date: 2020-02-04
Publication date: 2020-12-03
Also published as: CN111999801A

Abstract

The present application provides a planar lightwave circuit (PLC) chip, a TOSA, a BOSA, an optical module, and an optical network device. A magneto-optical structure is provided in a PLC chip to isolate reflected light, thereby reducing the volume and complexity of the PLC chip. The PLC chip comprises at least one optical transmission channel, at least one of the at least one optical transmission channel being provided with a filter; the input end of the optical transmission channel receiving an optical signal input by a laser diode (LD); and the filter being used for filtering out the part of the optical signal on the optical transmission channel where the power is lower than a threshold. The PLC chip also comprises a magneto-optical structure used for isolating reflected light entering the PLC chip.

Description

A PLC chip, TOSA, BOSA, optical module, and optical network equipment

This application requires the priority of a Chinese patent application filed with the Chinese Patent Office on May 27, 2019, the application number is 201910446404.6, and the application name is "a PLC chip, TOSA, BOSA, optical module, and optical network equipment". The entire content is incorporated into this application by reference.

Technical field

This application relates to the field of communications, in particular to a PLC chip, TOSA, BOSA, optical module, and optical network equipment.

Background technique

With the increase in network demand and the development of technology, the transmission rate of passive optical networks (PON) is getting higher and higher. Gigabit-capable passive optical network (GPON), a branch of PON, is the standard 10G Gigabit-capable passive optical network (XGPON), and Ethernet passive optical network (ethernet passive optical) Network, EPON) standard 10G Ethernet passive optical network (10G Ethernet passive optical network, 10G EPON), the single-wave rate reaches 10Gbps. The evolution from PON to 10G PON requires optical components, such as Optical Line Terminal (OLT), which can be compatible with the transmission from PON evolution to 10G PON.

In order to reduce the cost of the OLT, a combination of directly modulated laser (DML) and a filter can be used. Generally, the filter and the multiplexer are integrated in the same planar light wave circuit (PLC). The filter has the function of chirp management, which can repair the extinction ratio of DML. Specifically, light of different wavelengths can be coupled into the same optical path through a multiplexer, and then coupled into an optical fiber through an isolator.

The commonly used isolator is a spatial isolator with a relatively large volume. Therefore, coupling the isolator with the PLC will increase the length and complexity of the optical device, and increase the cost of the optical device.

Summary of the invention

The present application provides a PLC chip, TOSA, BOSA, optical module, and optical network equipment, which are used to isolate the reflected light by arranging a magneto-optical structure in the PLC chip to reduce the volume and complexity of the PLC chip.

In view of this, the first aspect of the present application provides a planar optical waveguide PLC chip, which is characterized by including: at least one optical transmission channel, and at least one of the at least one optical transmission channel is provided with a filter;

The input end of the optical transmission channel receives the optical signal input by the laser LD;

The filter is used to filter out the part of the optical signal on the optical transmission channel where the power is lower than the threshold;

The PLC chip also includes a magneto-optical structure, which is used to isolate the reflected light entering the PLC chip.

Therefore, in the PLC chip provided by the embodiment of the present application, magneto-optical materials are grown on the PLC chip to isolate the reflected light reflected into the PLC chip, which can prevent the reflected optical signal from affecting the performance of the LD, and reduce the optical transmission component. The volume reduces the length and complexity of the optical transmission component, and reduces the cost of the optical transmission component.

In a possible implementation manner, the PLC chip further includes a multiplexer, the number of optical transmission channels is at least two, and at least one of the at least two optical transmission channels is provided with a filter;

The output end of the optical transmission channel is connected to the input end of the multiplexer;

The multiplexer is used to multiplex the optical signals on each optical transmission channel and output the multiplexed signal.

In the embodiment of the present application, if the number of optical transmission channels is at least two, at least one of the at least two optical transmission channels may be provided with a filter. The multiplexer can multiplex the optical signals transmitted on at least two optical transmission channels to obtain multiplexed signals.

In a possible implementation manner, the PLC chip further includes: a polarization beam splitter (PBS) and a curved waveguide connected to one end of the PBS;

PBS is located at the output of the multiplexer or between the filter and the input of the multiplexer;

PBS is used to separate longitudinal wave TM and transverse wave TE in reflected light;

Bent waveguides are used to loss TE.

Therefore, in the embodiment of the present application, the PBS may be set at the output end of the multiplexer. When the magneto-optical isolator is arranged between the input end of the multiplexer and the LD, the PBS can also be arranged between the magneto-optical structure and the input end of the multiplexer, including between the filter and the input end of the multiplexer. The reflected light reflected to the multiplexer can be split. When the reflected light is TM mode light, it can be directly isolated by the PLC chip grown with magneto-optical material. When the reflected light includes TE mode light, it can pass through PBS It is separated and consumed by bending the waveguide to avoid reflection into the PLC chip.

In a possible implementation, the reflected light first passes through the PBS, and then passes through the magneto-optical structure. In the embodiments of the present application, the direction from the LD to the output end of the multiplexer can be understood as the forward direction, and the PBS is arranged after the magneto-optical isolator to ensure that the TM mode light output by the PBS can be isolated via the magneto-optical structure.

In a possible implementation manner, the magneto-optical structure is grown on the filter, and the magneto-optical structure is used to isolate the reflected light passing through the filter.

In a possible implementation, the magneto-optical structure is grown on the microring, and the magneto-optical structure is used to isolate the reflected light on the microring. In the embodiment of the present application, the magneto-optical structure can be grown on the microring, so that the microring has a chirp management function and can isolate reflected light.

In a possible implementation manner, a magneto-optical structure is grown on the multiplexer, and the magneto-optical structure is used to isolate the reflected light passing through the multiplexer. In the embodiment of the present application, the magneto-optical material can be grown on the multiplexer, so that the multiplexer not only has the multiplexing function, but also can isolate the reflected light. Reduce the size of the PLC chip and package complexity.

In a possible implementation, the magneto-optical structure is a magneto-optical isolator; the magneto-optical isolator includes a waveguide structure and a magneto-optical material grown on the waveguide structure;

The magneto-optical isolator is arranged at the output end of the multiplexer, or between the filter and the input end of the multiplexer, or between the input end of the optical transmission channel and the input end of the filter.

The magneto-optical isolator can be realized by optical waveguides and magneto-optical materials, which not only realizes the isolation function, but also reduces the size of the PLC chip and the packaging complexity.

In a possible implementation, the magneto-optical isolator is a Mach-Zinde MZ isolator, and the magneto-optical isolator is used to isolate the reflected light passing through the magneto-optical isolator. The magneto-optical isolator can be composed of MZ-type optical waveguides and magneto-optical materials in the PLC chip. Therefore, the magneto-optical isolator can be realized by the MZ-type optical waveguide and magneto-optical material, which not only realizes the isolation function, but also reduces the size of the PLC chip and the packaging complexity.

In a possible implementation, the filter is at least one of a micro-loop filter, a grating filter, and a Mach-Zinde MZ filter.

In a possible implementation, the magneto-optical structure is a magneto-optical oxide film.

In a possible implementation, the magneto-optical material is a magneto-optical oxide film.

In the embodiments of the present application, the magneto-optical material may be a magneto-optical oxide film. When the magneto-optical oxide film is grown on the PLC chip, a PLC chip with chirp management and multiplexing functions can be realized, and it can also have the function of isolating reflected light, and reduce the size of the PLC chip and the packaging complexity.

The second aspect of the present application provides a transmitter optical subassembly (TOSA). The TOSA may include at least one LD and the PLC chip in the first aspect or any one of the embodiments of the first aspect. Each of the PLC chips An LD is connected to the input end of an optical transmission channel, and the at least one LD can be used to generate laser light to obtain an optical signal.

In a possible implementation, TOSA may further include: at least one lens;

At least one lens is used to couple the multiplexed signal to the optical fiber to transmit the multiplexed signal through the optical fiber. In the embodiment of the present application, the TOSA may also include at least one lens, which may be used to couple the multiplexed signal to the optical fiber. For example, the first lens may specifically convert the light output by the PLC chip into parallel light, and then the second lens The two lenses couple the parallel light to the optical fiber to realize the transmission of the multi-wave signal.

The third aspect of the present application provides a Bi-direction Optical Subassembly (BOSA), and the BOSA may be the TOSA provided in the foregoing second aspect.

The fourth aspect of the present application provides an optical module, and the optical module includes the BOSA provided in the third aspect.

A fifth aspect of the present application provides an optical network device, which may include the optical module provided in the foregoing fourth aspect.

The PLC chip provided in the present application may include at least one optical transmission channel, and at least one of the at least one optical transmission channel is provided with a filter. The PLC chip also includes a magneto-optical structure, which is composed of magneto-optical materials and used to isolate the reflected light emitted into the PLC chip. Therefore, the reflected light signal can be prevented from affecting the performance of the LD. And compared to the spatial isolator, the PLC chip provided in the present application includes a magneto-optical structure of magneto-optical material, which can realize the isolation of reflected light without a large volume, which can reduce the volume of the PLC chip and reduce the light The length and complexity of the transmission component reduces the cost of the optical transmission component.

Description of the drawings

Figure 1 is a schematic diagram of an application scenario of an embodiment of the application;

2A is a schematic structural diagram of a PLC chip according to an embodiment of the application;

2B is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

3 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

4 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

FIG. 5 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

FIG. 6 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

FIG. 7 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

FIG. 8 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

9 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

FIG. 10 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

FIG. 11 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

FIG. 12 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

FIG. 13 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

14 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

15 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

16 is a schematic diagram of another structure of a PLC chip according to an embodiment of the application;

FIG. 17 is a schematic structural diagram of a TOSA according to an embodiment of the application.

Detailed ways

The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative work shall fall within the protection scope of this application.

The PLC chip provided in this application can be applied to a transmitter optical subassembly (TOSA). The TOSA may be included in an optical transceiver assembly (Bi-direction Optical Subassembly, BOSA). The BOSA can be applied to optical modules, which can be installed in optical network equipment.

The optical network equipment may include various optical network terminals, for example, an optical line terminal (OLT), an optical network unit (ONU), or an optical network terminal (ONT). Moreover, the optical network equipment can be applied to a variety of communication systems involving optical transmission, for example, it can include PON, GPON, XGPON, EPON, and so on.

Exemplarily, the communication system applied by the optical network equipment provided in this application may be as shown in FIG. 1. Among them, it may include at least one OLT, and at least one ONU or at least one ONT. The one OLT and three ONUs (ONU1, ONU2, ONU3) included in FIG. 1 are merely illustrative and not limited.

One or more ONUs are connected to one or more OLTs.

The OLT is the core component of the optical access network. The OLT is used to provide data for one or more ONUs connected, and to provide management and so on.

The ONU is used to receive data sent by the OLT, respond to the management commands of the OLT, buffer the user's Ethernet data, and send it to the upstream in the sending window allocated by the OLT.

In addition, an optical distribution network (ODN) may be included between the OLT and the ONU. The ODN (not shown in the figure) may be used to provide a transmission channel between the OLT and the ONU, and may also include other optical network equipment, etc. Etc., this application does not limit this, and it can be adjusted according to actual application scenarios.

The PLC chip provided in this application is introduced below.

The PLC chip provided in the present application may include at least one optical transmission channel, and at least one of the at least one optical transmission channel is provided with a filter. The input end of the optical transmission channel receives the optical signal input by the laser LD; the filter is used to filter out the part of the optical signal on the optical transmission channel where the power is lower than the threshold; the PLC chip also includes a magneto-optical structure. The structure is used to isolate the reflected light entering the PLC chip.

Among them, the magneto-optical structure may be composed of magneto-optical materials, or the magneto-optical structure may be a structure in which magneto-optical materials are grown. The magneto-optical structure can be realized in a variety of ways. The magneto-optical structure can be a structure covering various modules or components in the PLC chip, or a structure formed solely of magneto-optical materials and optical waveguides. Magneto-optical materials can isolate the reflected light.

Taking one of the optical transmission channels as an example, please refer to FIG. 2A and FIG. 2B, the schematic diagram of the PLC chip structure provided in this application.

The PLC chip may include an optical transmission channel 201 and a magneto-optical structure 202, and the optical transmission channel 201 is provided with a filter 2011.

The input end of the optical transmission channel 201 receives the optical signal from the LD1, and the filter 2011 can filter out the part of the optical signal whose power is lower than the threshold.

The number of the optical transmission channel 201 may be one or more. The magneto-optical structure can be set on the optical transmission channel or on the output end of the PLC chip.

As shown in FIG. 2A, the magneto-optical structure can be an independent component and can be arranged at the output end of the filter 2011.

The magneto-optical structure can also be a structure covering or sleeved on various components in the PLC chip. The magneto-optical structure includes a structure composed of magneto-optical materials. Therefore, it can also be understood as a magneto-optical material grown on the PLC chip.

In an implementation manner, the filter 2011 may be a filter with a chirp management function. The filter 2011 can filter out the part of the optical signal whose power is lower than the threshold, and can realize the chirp management of the optical signal.

Specifically, in the optical signal output by the LD, the signal frequency changes with time, and the pulse front and rear edges may have frequency changes due to modulation, which broadens the spectrum of the optical signal. The spreading of the frequency spectrum can be described by the chirp coefficient, and the chirp coefficient can also be called the linewidth spreading factor. The spectrum broadening can be linear or non-linear. Therefore, a filter with a chirp management function can be used to filter out the lower power part of the optical signal, adjust the extinction ratio of the optical signal, and realize the chirp management of the optical signal.

In one implementation, if the optical transmission channel 201 includes both the filter 2011 and the magneto-optical structure 202, the input optical signal can be chirped management, and the LD1 may be a laser that generates the optical signal that needs chirp management. It can also be a laser that generates optical signals that do not require chirp management. For example, LD1 may be a directly modulated laser (DML) or an electroabsorption modulated distributed feedback laser (EML). Generally, in order to improve the effective utilization of each component in the PLC chip, LD1 may be a DML, and the PLC chip provided in this application can effectively repair the extinction ratio of the DML.

In the aforementioned PLC chips shown in Figures 2A and 2B, one optical transmission channel is taken as an example for description. The number of optical transmission channels can be one or more, and at least one of the optical transmission channels is provided with a filter. .

Generally, if a certain optical transmission channel receives the optical signal input by the EML, the filter may not be provided on this channel, of course, the filter may also be selected.

Exemplarily, taking two optical transmission channels as an example, as shown in FIG. 3, the PLC chip may include two optical transmission channels 201 and a magneto-optical structure 202 (not shown in the figure). One of the optical transmission channels 201 is The filter 2011 is provided, which is referred to as the first optical transmission channel hereinafter, and the filter 2011 is not provided on the other optical transmission channel 201, which is referred to as the second optical transmission channel hereinafter.

The first optical transmission channel receives the optical signal input by LD1 and the second optical transmission channel receives the optical signal input by LD2.

Generally, the first optical transmission channel is provided with a filter 2011 that can perform chirp management, and the optical signal output by the DML usually needs to be chirp management, therefore, LD1 may be a DML. Of course, LD1 can also be EML.

If a filter is not provided on the second optical transmission, the input optical signal cannot be chirped management, therefore, LD2 can be an EML.

If the PLC chip includes multiple optical transmission channels, as shown in FIG. 4, the multiple optical transmission channels may include one or more first optical transmission channels and one or more second optical transmission channels.

In another embodiment, if the PLC chip includes multiple optical transmission channels, the multiple optical transmission channels may all be the first transmission channels.

Therefore, in the embodiments of the present application, the PLC chip may include multiple optical transmission channels, and whether each optical transmission channel includes a filter can be adjusted according to the corresponding LD. If the LD is a relatively poor extinction LD, the corresponding optical transmission channel can be equipped with a filter to repair the extinction ratio of the LD. If the LD is an LD with better extinction, the corresponding optical transmission channel may not be provided with a filter to reduce the cost of the PLC chip. Therefore, the PLC chip provided by the embodiment of the present application can be applied to both DML and EML. For example, if the LD is a low-cost DML, a filter can be set in the corresponding optical transmission channel, and the low-power part can be filtered out through the filter, and the optical signal generated by the DML can be chirped management.

Generally, DML can convert electrical signals into optical signals. Since the amount of chirp of the optical signal generated by DML is usually relatively large, a filter with chirp management can be added to the PLC chip to perform chirp management on the optical signal generated by the DML and filter out the optical signal output by the DML The low-power part in the middle makes it easier to identify or decode when the subsequent receiving end receives the synthesized multiplexed signal.

In one embodiment, if the PLC chip only includes one optical transmission channel, there is no need to perform multiplexing, and furthermore, there is no need to provide a multiplexer, which can reduce the cost. If the PCL chip includes multiple optical transmission channels, the optical signals transmitted on the multiple optical transmission channels need to be multiplexed. The following describes the PLC chip including the multiplexer.

In a specific implementation manner, the optical signal in the PLC chip may be transmitted by an optical waveguide, and the PLC chip may include an optical waveguide structure. Exemplarily, the PLC chip can receive the optical signal generated by the LD through an optical waveguide, and filters, multiplexers or other devices may also be connected through an optical waveguide. The optical waveguide in each optical transmission channel can transmit optical signals, and the optical waveguide at the output end of the multiplexer can output multiplexed signals, etc. The optical waveguides included in the PLC chip will not be repeated in the following embodiments of the application.

As shown in FIG. 5, the embodiment of the present application also provides another PLC chip.

Wherein, the PLC chip may include multiple optical transmission channels 201 and a magneto-optical structure 202 (not shown in FIG. 5), and may also include a multiplexer 504.

Wherein, the output end of each optical transmission channel 201 is connected to the input end of the multiplexer.

The multiplexer 504 may multiplex the input optical signal to obtain a multiplexed signal, and then output the multiplexed signal through the output terminal of the multiplexer 504.

In the embodiment of the present application, a filter may be set on one or more optical transmission channels to filter out the low-power part of the optical signal input by the LD, so as to realize the chirp management of the optical signal. The magneto-optical structure realizes the isolation of reflected light. And the optical signals on multiple optical transmission channels are multiplexed through the multiplexer. Therefore, a non-reciprocal PLC chip with chirp management and multiplexing functions can be realized.

In one possible implementation, the magneto-optical structure is grown on the filter.

Specifically, as shown in FIG. 6, an embodiment of the present application also provides another PLC chip.

In the PLC chip, the magneto-optical structure is covered on one or more filters 2011.

The magneto-optical structure includes a structure formed of a magneto-optical material, or the magneto-optical structure is composed of a magneto-optical material. The magneto-optical structure can be a magneto-optical film covering the filter, or it can be another structure coupled with the filter structure.

Magneto-optical materials can make the light transmitted in the forward direction and the light transmitted in the reverse direction differ by half of the free spectral range (FSR). Therefore, the reflected light will not pass through the filter and realize the reflection Light isolation.

In the embodiments of the present application, a magneto-optical structure can be grown on the filter, and the reflected light reflected to the filter can be filtered out. In addition, the filter also has the function of chirp management. Therefore, the PLC chip provided in the embodiment of the present application has the function of reverse isolation and the function of chirp management. And compared to a separate isolation device, it can effectively reduce the size of the PLC chip.

In another possible implementation, the magneto-optical structure is grown on the multiplexer.

Specifically, as shown in FIG. 7, an embodiment of the present application also provides another PLC chip.

In this PLC chip, the magneto-optical structure is grown on the multiplexer 504.

The magneto-optical structure may include a structure formed of a magneto-optical material, or the magneto-optical structure is composed of a magneto-optical material. The magneto-optical structure can be a magneto-optical film covering the filter, or it can be another structure coupled with the filter structure.

The magneto-optical structure is covered on the multiplexer, which can make the difference between the forward transmission light and the reverse transmission light on the multiplexer by half FSR. Therefore, the emitted light cannot pass through the multiplexer, and the reflected light isolation.

In the embodiment of the present application, a magneto-optical structure can be grown on the multiplexer, and the reflected light reflected to the multiplexer can be filtered out. So that the multiplexer can not only realize the function of combining waves, but also realize the isolation of reflected light. And compared to a separate isolation device, it can effectively reduce the size of the PLC chip.

In another possible implementation, the magneto-optical structure is a magneto-optical isolator. The magneto-optical isolator includes a waveguide structure on which magneto-optical material is grown.

Specifically, please refer to FIG. 8. The embodiment of the present application also provides another PLC chip.

In the PLC chip, the magneto-optical structure may be a magneto-optical isolator, and the magneto-optical isolator 202 includes a waveguide structure grown with magneto-optical material.

The magneto-optical isolator filters out the emitted light reflected to the magneto-optical isolator through magneto-optical materials grown on the waveguide.

The magneto-optical isolator 202 can be arranged at the output end of the multiplexer. The input end of the magneto-optical isolator 202 receives the multiplexed signal from the multiplexer, and then outputs the multiplexed signal.

The output end of the magneto-optical isolator 202 may receive external reflected light. The magneto-optical material grown on the waveguide of the magneto-optical isolator makes the forward transmission multiplexed signal and the reflected light differ by half FSR, which can make the reflection Light cannot pass through the magneto-optical isolator 202.

In another possible implementation manner, the magneto-optical isolator 202 may also be provided at the input end of the multiplexer. As shown in FIG. 9, when the magneto-optical isolator 202 is arranged at the input end of the multiplexer, it can be set at the output end of each optical transmission channel before the optical signal output by each optical transmission channel is combined. The isolator 202 is used to isolate the reflected light reflected to each optical transmission channel.

In another possible implementation manner, the magneto-optical isolator 202 may also be arranged between the input end of each optical transmission channel and the input end of the filter. It can be understood that, as shown in Figure 10, the magneto-optical isolator is arranged after the LD and before the filter. The magneto-optical isolator 202 can receive the optical signal from the LD in the forward direction and the reflected light in the reverse direction. The magneto-optical isolator is grown with a waveguide structure made of magneto-optical materials, which can isolate the reflected light reflected to each optical transmission channel.

It should be noted that, in the above method of setting a magneto-optical isolator on each optical transmission channel, if a filter is not included on a certain optical transmission channel, a magneto-optical isolator can be installed on the optical transmission channel, or There is no need to set up a magneto-optical isolator.

In the embodiment of the present application, a magneto-optical isolator can be formed by growing magneto-optical materials on the waveguide structure, and the magneto-optical isolator can be arranged in the PLC chip to isolate the reflected light and prevent the reflected light from being emitted to the laser. Affect the performance of the laser. Compared with an independent spatial isolator, magneto-optical materials are grown on the waveguide structure, and the reflected light can be isolated without the need for a larger-volume waveguide structure, which can reduce the size of the PLC chip.

In some possible implementations, the aforementioned filter may be a filter with a chirp management function, for example, a micro-loop filter, a grating filter, a Mach-Zehnder (MZ) filter, etc., Specific adjustments can be made according to actual application scenarios, which are not limited in this application.

Exemplarily, in the following embodiments, a micro-ring filter is used for illustrative description, and the micro-ring filter is simply referred to as a micro-ring in the following. In practical applications, the micro-loop filter can also be replaced with grating filters, MZ filters, and other devices with filtering functions.

As shown in FIG. 11, the PLC chip can be connected with at least one LD (LD1, LD2...LDN as shown in FIG. 11). The PLC chip includes a plurality of N optical transmission channels 201, and one or more of the optical transmission channels may include the micro ring 2011. The PLC chip also includes a multiplexer 504, and N is a positive integer greater than one.

As shown in FIG. 12, magneto-optical materials can be grown on the microring 2011, and it can also be understood that the magneto-optical structure 202 is a structure formed by the magneto-optical materials grown on the microring.

Hereinafter, the direction of light from the LD to the multiplexer through the microring is referred to as the forward direction, and the direction of the light from the multiplexer to the microring is the reverse.

During forward transmission, the micro-ring 2011 can be connected to a current source, and the micro-ring is turned on periodically. When the optical signal output by the LD is input from the input end of the micro ring, the micro ring 2011 is turned on, and the output end of the micro ring 2011 is in a completely light-on state. When the microring 2011 is not conducting, the microring 2011 is in a non-light-passing state and does not pass optical signals. Therefore, it is possible to implement chirp management on the input optical signal through the micro-ring filter, adjust the front and rear edges of the optical signal, and restore the extinction ratio of the optical signal. For example, the "0" power in the laser signal sent by the LD can be filtered through the micro ring, and the extinction ratio can be improved, thereby realizing the chirp management of the laser signal.

When the reflected light is transmitted in the reverse direction, since the magneto-optical material grows on the microring 2011, the propagation constant of the microring is different in the forward and reverse directions, and the difference between the forward direction and the reverse direction is half FSR. Therefore, the reflected light cannot pass through Micro ring.

More specifically, in practical applications, the period of the microring and the range covered by the magneto-optical material can be adjusted according to the actual light signal passing through. In this way, the forward and reverse propagation constants are adjusted, so that the laser signal passing in the forward direction differs from the reflected light in the reverse direction by half FSR, so that the reflected light cannot pass through the micro ring. For example, if the difference between the forward direction and the reverse direction is 0.5 cycles, then the conduction period of the microring and the growth range of the magneto-optical material can be adjusted at the same time to adjust the forward and reverse constants. This makes the forward and reverse transmissions differ by 0.5 cycles. Then, when the forward conduction is conducted, the reverse conduction cannot be conducted, thereby isolating the reflected light, preventing the reflected light from passing through the micro ring, and affecting the performance of the LD to emit laser light.

It should be understood that, for more detailed description, only one complete microring is shown in FIG. 12, and other microrings among at least one microring included in the PLC chip are not shown in FIG. 12.

In addition, in Figure 12, only the scene where one LD corresponds to one microring is shown. In practical applications, one LD can be connected to one or more microrings, that is, the output terminal of one LD can be connected in series or in parallel. Microrings, the specific number or connection manner of microrings can be adjusted according to actual application scenarios, and the embodiments of the present application are merely illustrative and not limited.

Therefore, in the embodiment of the present application, the microring in the PLC chip is grown with magneto-optical material, so that the PLC chip has the functions of chirp management and reverse isolation, and also has the multiplexing function of the multiplexer. Moreover, under the premise of not destroying the original microring, the microring and the magneto-optical material can be integrated together to realize a non-reciprocal filter with isolation function, which can effectively reduce the size of the PLC chip and reduce the BOSA The packaging cost and packaging complexity of the package, thereby reducing the cost of OLT.

In some possible implementations, the aforementioned multiplexer can be an MZ-type multiplexer, a grating interference multiplexer, a parallel optical waveguide multiplexer, etc., which can be adjusted according to actual application scenarios. limited.

Illustratively, in the following embodiments, an MZ-type multiplexer is taken as an example for description. In practical applications, the MZ-type multiplexer can also be replaced with a grating interference multiplexer, a parallel optical waveguide multiplexer, and other devices with multiplexing functions.

As shown in FIG. 13, the multiplexer 504 is an MZ type multiplexer, and the multiplexer 504 includes a magneto-optical structure 202. The magneto-optical structure can be a structure formed of a magneto-optical material, or it can be understood as a magneto-optical material grown on an MZ-type multiplexer.

During forward transmission, the arm lengths of the two arms of the MZ-type multiplexer are different, and the arm length difference between the two arms of the MZ-type multiplexer is a preset value, which can be specifically based on the wavelength of the actual signal passed Or adjust the phase, the wavelength or phase of the reflected light, etc. The phase difference between the two arms is 2nπ+π/2, and the magneto-optical material is grown on the MZ-type multiplexer. Due to the magneto-optical material, the phase difference generated by the optical waveguide of the multiplexer is -π/2. The total phase difference of the arm is 2nπ, so the chirped signal in the forward direction interferes with the MZ-type combiner constructively, and the forward conduction is conducted.

In reverse transmission, since the phase difference between the arm lengths of the two arms of the MZ-type multiplexer is 2nπ+π/2, and the magneto-optical material grows on the MZ-type multiplexer, the magneto-optical material causes the multiplexing The phase difference produced by the optical waveguide of the filter is π/2. Therefore, the total phase difference between the two arms is 2nπ+π, which makes the reflected light interfere with the MZ-type multiplexer and cancel it. Therefore, the reflected light cannot pass through the multiplexer. The multiplexer grown with magneto-optical materials can prevent the reflected light from passing through the multiplexer and isolate the reflected light. The reflected light is a TM mode wave separated by the PBS, or a TE mode wave separated by the PBS is converted by a polarization rotator to obtain a TM mode wave.

Specifically, the arm length of the two arms of the MZ-type multiplexer and the growth range of the magneto-optical material can be combined for adjustment. Generally, it can be adjusted according to the formula:

Determine the arm length difference L _{1 between the} two arms. Among them, FSR is the free spectral region, Δβ is the signal phase difference passed by the MZ-type multiplexer, and Δλ is the wavelength passed by the MZ-type multiplexer. The growth of magneto-optical material on the multiplexer will affect Δβ. Therefore, combining the growth range of the magneto-optical material and the arm length difference L _{1 between the} two arms of the multiplexer can determine the forward wavelength passed by the multiplexer. specifically,

Among them, M is the magnetic induction intensity, ω is the frequency of the propagating signal, ε is the dielectric constant in vacuum, β is the propagation constant, K is the vacuum propagation constant, E is the electric field strength,

H is the magnetic field strength. Therefore, it is possible to adjust Δβ by adjusting the growth range of the magneto-optical material, and then adjust the forward and reverse wavelengths of the multiplexer after growing the magneto-optical material, so that the forward and reverse waves passing through the multiplexer differ by half A FSR, which in turn prevents the reflected light from passing through the multiplexer, and isolates the reflected light.

Therefore, in the embodiment of the present application, the multiplexer in the PLC chip is grown with magneto-optical materials, so that the PLC chip has the functions of chirp management and reverse isolation, and also has the multiplexing function of the multiplexer. Integrating the multiplexer with the magneto-optical material can realize non-reciprocal filter components with isolation function, which can effectively reduce the size of the PLC chip, and can reduce the packaging cost and packaging complexity of BOSA, thereby reducing the OLT cost.

Of course, in addition to the magneto-optical material that can be produced in either the micro-ring or the multiplexer, the magneto-optical material can also be grown on both the micro-ring and the multiplexer, which can be adjusted according to actual application scenarios. This is not limited.

In another implementation, the magneto-optical structure can also be a magneto-optical isolator. The magneto-optical isolator includes a waveguide structure grown with magneto-optical material.

The waveguide structure in the magneto-optical isolator may have a curved shape. Illustratively, a magneto-optical isolator with an MZ-type structure is used for description in the following embodiments. In practical applications, the magneto-optical isolator can include various curved waveguides, and magneto-optical materials are applied to the waveguide.

As shown in FIG. 14, the PLC chip may include a micro-ring filter 2011, a multiplexer 504, and a magneto-optical isolator 202.

Wherein, the magneto-optical isolator 202 may be an MZ ring-shaped waveguide structure, and magneto-optical materials are grown on the MZ ring-shaped waveguide structure.

The principle of isolating reflected light is similar to that of the MZ-type multiplexer in FIG. 13 and will not be repeated here.

During forward transmission, the laser signal generated by at least one LD can pass through at least one micro-ring for chirp management to obtain at least one chirp signal, and then the at least one chirp signal is combined by the multiplexer to obtain a multiplexed signal , And then output the combined signal through the magneto-optical isolator. The magneto-optical isolator can output multiplexed signals while isolating and reflecting the reflected light of the magneto-optical isolator.

Therefore, in the embodiment of the present application, the magneto-optical isolator in the PLC chip is grown with magneto-optical materials, so that the PLC chip has the functions of chirp management and reverse isolation, and the multiplexing function of the multiplexer. The isolator is integrated with the magneto-optical material to obtain a magneto-optical isolator, which can realize a non-reciprocal filter device with isolation function. The magneto-optical isolator has a low insertion loss in the forward transmission direction, and has a great attenuation effect on the reverse transmission light, so it can isolate the reflected light reflected into the PLC chip. Compared with space-type isolators, magneto-optical isolators can effectively reduce the size and volume of PLC chips, reduce the packaging cost of BOSA, and thereby reduce the cost of OLT. Moreover, compared to the spatial isolator that is separately coupled with the PLC chip, the magneto-optical isolator provided in the embodiments of the present application can be directly integrated on the PLC component without re-packaging the PLC chip and the spatial isolator, thereby reducing TOSA The complexity and volume of BOSA and OLT reduce the cost of optical transceiver components and further reduce the space isolator.

It should be noted that the magneto-optical isolator 202 can be set at the output end of the multiplexer in FIG. 14 as well as the input end of the multiplexer. Of course, it can also be set at the input end and the input end of the multiplexer at the same time. The specific setting position of the output terminal can be adjusted according to actual application scenarios, and the embodiments of the present application are merely illustrative and not limited.

In a possible implementation, the aforementioned magneto-optical material or magneto-optical film may be a magneto-optical oxide film. The magneto-optical oxide film can be grown in a PLC chip. To isolate the reflected light reflected into the PLC chip. Moreover, compared with a separate spatial isolator, the magneto-optical oxide film provided in the embodiments of the present application can reduce the volume of the PLC chip without the need to couple an isolator, reduce the packaging complexity and volume of the BOSA module, and reduce the BOSA module the cost of.

Reflected light can be divided into transverse electric (TE) and transverse magnetic (TM). The light isolated by the magneto-optical structure provided in this application is light in TM mode. Therefore, when there is light in TE mode, It is also necessary to further isolate the TE mode light.

In a possible implementation manner, a polarization beam splitter (PBS) and a curved optical waveguide may be provided in the PLC chip. The PBS can divide the reflected light into TE mode light and TM mode light. The TE mode light can be lost by the curved optical waveguide, and the TE mode light can be isolated by the magneto-optical structure.

In some possible implementations, the PBS can be set at the output end of the multiplexer. When the magneto-optical structure is set at the input end of the multiplexer, the PBS can also be set between the magneto-optical structure and the input end of the multiplexer. .

Exemplarily, as shown in FIG. 15, a PBS 1505 and a curved optical waveguide 1506 may be provided in the PLC chip. PBS1505 is set at the output of the multiplexer. The first end of PBS1505 is connected to the output end of the multiplexer, the second end of PBS1505 outputs the multiplexed signal, and the third end of PBS1505 is connected to curved optical waveguide 1506.

The reflected light is input to the PBS from the second end of the PBS1505. The PBS1505 splits the reflected light. When the reflected light is split to obtain the TM mode light, it will be directly transmitted to the multiplexer, and the magneto-optical material will be grown through the multiplexer. , Magneto-optical material or magneto-optical isolator is grown on the micro ring to isolate the reflected light of TM mode. When the reflected light is split to obtain TE mode light, the PBS 1505 transmits the TE mode light to the curved optical waveguide 1506, and the TE mode light is lost after passing through the curved optical waveguide. Therefore, the isolation of the TE mode reflected light is achieved.

Generally, the PBS may include a dichroic prism, the electric vector of the TE mode wave is perpendicular to the incident plane, and the electric vector of the TM mode wave is in the incident plane.

The curved optical waveguide 1506 may be a single section of curved optical waveguide, or may be a curved optical waveguide in the PLC chip.

Exemplarily, one or more PBS1505 is provided between the magneto-optical structure and the multiplexer. As shown in FIG. 16, one or more PBS1505 and one or more curved optical waveguides 1506 can be provided at the input end of the multiplexer in the PLC chip.

Wherein, the PBS 1505 and the curved optical waveguide 1506 can be arranged in the optical transmission channel with the filter. For optical transmission channels without filters, PBS1505 or PBS1505 can be set, which can be adjusted according to actual application scenarios.

The first end of any PBS1505 is connected to the output end of the filter 2011, the second end of the PBS1505 outputs the multiplexed signal, and the third end of the PBS1505 is connected to the curved optical waveguide 1506.

The reflected light is first input from the second end of the PBS1505, and the PBS1505 splits the reflected light. When the reflected light is a TM mode wave, it will be transmitted directly to the multiplexer, and the TM mode reflected light will be isolated by growing magneto-optical material or magneto-optical isolator on the microring. When the reflected light is split to obtain TE mode light, the PBS 1505 transmits the TE mode light to the curved optical waveguide 1506, and the TE mode light is lost after passing through the curved optical waveguide. Therefore, the isolation of the TE mode reflected light is achieved.

In another implementation, in addition to eliminating the TE mode light by the first curved optical waveguide, it is also possible to use a polarization rotator to convert the TE mode to the TM mode wave, and to grow the magneto-optical wave through the multiplexer. Magneto-optical material or magneto-optical isolator is grown on the material and microring to isolate the reflected light of TM mode.

In another implementation, PBS can also be set at the output end of the multiplexer, and PBS can also be set between the multiplexer and the magneto-optical structure at the same time to achieve a more comprehensive conversion of reflections and more comprehensive isolation of reflections Light.

In some possible implementations, in addition to integrating the micro-ring and the multiplexer, the PLC chip can also integrate other optical devices, for example, an optical splitter. This embodiment of the application does not limit this, and will not proceed one by one. Specific instructions.

The aforementioned PLC chip provided in this application is described in detail, and this application also provides a TOSA, BOSA, optical module, and optical network equipment, etc., which are described separately below.

The embodiment of the present application provides a TOSA. The TOSA may include at least one LD and the PLC chip in any one of the embodiments in FIGS. 2A-16. For the specific structure of the PLC chip, please refer to the foregoing FIGS. 2A-16.

Exemplarily, as shown in FIG. 17, this application also provides a TOSA. The TOSA may include a PLC chip 20 and at least one LD1701.

At least one LD701 is used to generate laser light to obtain an optical signal, which is input to the PLC chip 20.

The PLC chip 20 may include one or more optical transmission channels and magneto-optical structures. At least one of the one or more optical transmission channels is provided with a filter. The magneto-optical structure is used to isolate reflected light.

When there are multiple optical transmission channels, the PLC chip also includes a multiplexer. The multiplexer is used to multiplex optical signals transmitted on multiple optical transmission channels to obtain multiplexed signals.

The at least one LD may include a DML or an EML. When one of the LDs is a DML, the PLC chip is provided with a filter in the optical transmission channel that receives the optical signal generated by the LD. When one of the LDs is EML, in the optical transmission channel that receives the optical signal generated by the LD in the PLC chip, a filter may or may not be provided.

In the embodiment of the present application, the laser signal generated by the LD can be chirped management by the filter, and the reflected light can be isolated by the magneto-optical structure. It can realize non-reciprocal TOSA with chirp management. Moreover, the magneto-optical structure in the embodiment of the present application is a structure formed of magneto-optical materials. Compared with the spatial isolator, the size and complexity of the PLC chip can be reduced, thereby reducing the size and complexity of the TOSA.

The embodiment of the present application also provides a BOSA, and the BOSA may include a TOSA and an optical receiving assembly (Receiver Optical Subassembly, ROSA).

The TOSA may be the TOSA provided in the present application, and the TOSA includes the PLC chip in any of the aforementioned embodiments in FIGS. 2A-16. The TOSA can be used to transmit optical signals.

ROSA may include filters, wavelength division multiplexers, lens arrays, light receiving PD arrays, and so on. ROSA can be used to receive optical signals.

The BOSA provided by the embodiments of the present application may include the PLC chip in any of the embodiments in FIGS. 2A-16, and the reflected light can be isolated by growing a magneto-optical structure in the PLC chip. It prevents the reflected light from affecting the performance of the LD, reduces the volume of the PLC chip, reduces the size and complexity of the BOSA, and reduces the packaging cost of the BOSA.

Based on the BOSA, an embodiment of the present application also provides an optical module. The optical module provided in this application may include the BOSA, and other modules, such as a transmitting circuit, a receiving circuit, a control circuit, and so on.

The BOSA may include the PLC chip in any of the embodiments in FIGS. 2A-16, and the reflected light can be isolated by growing a magneto-optical structure in the PLC chip. It prevents the reflected light from affecting the performance of the LD, reduces the size of the PLC chip, and reduces the size and complexity of the BOSA, thereby reducing the size and complexity of the optical module, and reducing the cost of the optical module.

Based on the optical module, an embodiment of the present application also provides an optical network device. The optical network device may include one or more optical modules, and may also include a single board, a control circuit, etc. The components included in different application scenarios may be different, and this application will not repeat them one by one.

For example, BOSA includes a transmitting part and a receiving part, the TOSA provided in this application can be applied to the transmitting part of BOSA, and BOSA can be applied to optical modules. For example, the BOSA may belong to a COMBO unit or a Dense Wavelength Division Multiplexing (DWDM) unit. COMBO unit or DWDM unit can be applied to optical network equipment. Optical network equipment may include network equipment with optical communication functions such as OLT, ONU, and ONT.

The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, without having to use To describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments described herein can be implemented in an order other than the content illustrated or described herein. In addition, the terms "including" and "having" and any variations of them are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to the clearly listed Those steps or units may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or equipment.

Claims

A planar optical waveguide PLC chip, characterized by comprising: at least one optical transmission channel, at least one of the at least one optical transmission channel is provided with a filter;

The input end of the optical transmission channel receives the optical signal input by the laser LD;

The filter is used to filter out the part of the optical signal on the optical transmission channel where the power is lower than the threshold;

The PLC chip also includes a magneto-optical structure for isolating the reflected light entering the PLC chip.
The PLC chip according to claim 1, wherein the PLC chip further comprises a multiplexer, the number of the optical transmission channels is at least two, and at least one of the at least two optical transmission channels is optically transmitted The filter is provided on the channel;

The output end of the optical transmission channel is connected to the input end of the multiplexer;

The multiplexer is used to multiplex the optical signals on each of the optical transmission channels to output multiplexed signals.
The PLC chip according to claim 2, wherein the PLC chip further comprises: a polarization beam splitter PBS and a curved waveguide connected to one end of the PBS;

The PBS is provided at the output end of the multiplexer, or between the filter and the input end of the multiplexer;

The PBS is used to separate longitudinal waves TM and transverse waves TE in the reflected light;

The curved waveguide is used to loss the TE.
3. The PLC chip of claim 3, wherein the reflected light first passes through the PBS, and then passes through the magneto-optical structure.
The PLC chip according to any one of claims 1 to 4, wherein:

The magneto-optical structure is grown on the filter, and the magneto-optical structure is used to isolate the reflected light passing through the filter.
The PLC chip according to any one of claims 2 to 4, wherein:

The magneto-optical structure is grown on the multiplexer, and the magneto-optical structure is used to isolate the reflected light passing through the multiplexer.
The PLC chip according to any one of claims 2 to 4, wherein the magneto-optical structure is a magneto-optical isolator; the magneto-optical isolator includes a waveguide structure and a magneto-optical structure grown on the waveguide structure. material;

The magneto-optical isolator is provided at the output end of the multiplexer, or between the filter and the input end of the multiplexer, or between the input end of the optical transmission channel and the Between the input ends of the filter.
8. The PLC chip of claim 7, wherein the magneto-optical isolator is a Mach-Zinde MZ isolator, and the magneto-optical isolator is used to isolate the reflected light passing through the magneto-optical isolator.
The PLC chip according to any one of claims 1-7, wherein the filter is at least one of a micro-loop filter, a grating filter, and a Mach-Zinde MZ filter.
The PLC chip of claim 5 or 6, wherein the magneto-optical structure is a magneto-optical oxide film.
The PLC chip of claim 7 or 8, wherein the magneto-optical material is a magneto-optical oxide film.
An optical emitting component TOSA, characterized in that, the TOSA comprises: at least one laser LD and the PLC chip according to any one of claims 1-11; the input end of each optical transmission channel is connected to one of the LD, the LD is used to generate laser light.
An optical transceiver component BOSA, characterized in that, the BOSA comprises the TOSA according to claim 12.
An optical module, characterized in that the optical module comprises the BOSA according to claim 13.
An optical network equipment, wherein the optical network equipment comprises the optical module according to claim 14.