Optical waveguide structure, preparation method of optical waveguide structure and electronic equipment

Abstract

The invention provides an optical waveguide structure and a preparation method of the optical waveguide structure, and is applied to the field of optical communication. The optical waveguide structure comprises a substrate, a waveguide, a gain module and a cladding. Wherein the waveguide and the gain module are located between the substrate and the cladding, the refractive indexes of the waveguide and the gain module are the same, and the refractive indexes of the waveguide and the gain module are larger than those of the substrate and the cladding. And the gain module is contacted with the waveguide. Wherein the waveguide is used for transmitting optical signals, and the gain module is used for amplifying the optical signals.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical communications, and in particular to an optical waveguide structure, a method for preparing the optical waveguide structure, and an electronic device. Background Art

[0002] As the complexity and scale of integrated optical systems increase, the coupling and packaging of more optical components on larger-sized optical waveguide substrates will cause higher optical losses, which will lead to increasingly higher optical losses between boards that will no longer be easy to ignore.

[0003] Currently, optical amplification components are usually used to compensate for the transmission loss of optical signals. For example, the Er-doped Waveguide Amplifier (EDWA). The optical amplification principle of EDWA is to excite the doped erbium ions with pump light, so that the electrons of the erbium ions transition from the ground state to the excited state with a high energy level. At this time, when the optical signal passes through, the excited state electrons will undergo stimulated radiation effect and emit a large number of photons with the same wavelength to amplify the optical signal. Among them, EDWA is usually used as an optical transmission relay, that is, it receives the optical signal on a waveguide, amplifies it, and then transmits it to the next waveguide.

[0004] If EDWA is used to compensate for the transmission loss on the optical waveguide substrate, the EDWA needs to be coupled and integrated with the waveguide in the optical waveguide substrate, which brings difficulties to the packaging of the integrated optical system. Summary of the invention

[0005] The embodiment of the present application provides an optical waveguide structure and a method for preparing the optical waveguide structure. In the process of preparing the optical waveguide structure, a waveguide for optical signal transmission and a gain module for optical signal compensation are integrated, thus avoiding the coupling and mounting of the waveguide with other independent amplifying elements, thereby greatly reducing the complexity of the system-level packaging and improving the integration of the entire optical system.

[0006] In the first aspect, an embodiment of the present application provides an optical waveguide structure, which includes: a substrate, a waveguide, a gain module and a cladding. The waveguide and the gain module are wrapped between the substrate and the cladding. The refractive index of the waveguide and the gain module is greater than the refractive index of the substrate and the cladding. The waveguide is used to transmit optical signals, and the gain module is used to amplify the optical signals transmitted in the waveguide. Therefore, the refractive index of the gain module is close to that of the waveguide, and the gain module is in contact with the waveguide, so that the optical signal in the waveguide can be transmitted to the gain module, and then transmitted back to the waveguide after being amplified by the gain module.

[0007] In the design of this new optical waveguide structure, the waveguide for optical signal transmission and the gain module for amplifying the optical signal are integrated in the optical waveguide structure. In this way, when the optical waveguide structure transmits the optical signal, the gain module can directly compensate for the transmission loss of the optical signal without the need for an independent amplifier to amplify the optical signal. In this way, the coupling and mounting of the waveguide and the independent amplifier element are avoided, and there is no need to integrate the waveguide and the independent amplifier element. This greatly reduces the complexity of the system-level packaging and improves the integration of the entire optical system.

[0008] In an optional embodiment, the waveguide used for optical signal transmission in the optical waveguide structure is a passive waveguide, and the gain module is an active waveguide doped with gain ions. In addition, the length of the passive waveguide used for optical signal transmission is greater than the length of the active waveguide for compensating the optical signal. In this way, the optical signal is transmitted along the waveguide, and is transferred to the active waveguide when passing through the gain module, and the gain ions in the active waveguide realize the transition of electrons from the ground state to the high-energy excited state under the action of the pump light, so that the excited state electrons will undergo stimulated radiation effect, emitting a large number of photons of the same wavelength to amplify and compensate the optical signal, and then the amplified and compensated optical signal is transmitted back to the passive waveguide, thereby reducing the optical loss in the optical waveguide structure.

[0009] In an optional embodiment, the cross section of the waveguide is circular, so that the optical transmission mode field of the waveguide will be close to circular symmetry, further reducing the transmission loss of the optical signal. The gain module can be set on one side of the waveguide axial direction, contacting the axial surface of the waveguide, or can be set at both ends of the waveguide, contacting the circumferential surface of the waveguide, without specific limitation.

[0010] In an optional embodiment, the optical waveguide structure may include a plurality of gain modules, which may be sequentially spaced along the direction in which the waveguide extends and on a side of the waveguide away from the substrate, and all of which are in contact with the axial surface of the waveguide. In this way, the optical signal in the waveguide may be compensated multiple times, thereby improving the transmission performance of the optical signal.

[0011] In an optional embodiment, when the gain module amplifies the optical signal, it needs to absorb the pump light first to realize the transition of the electron from the ground state to the high-energy excited state. Therefore, the optical waveguide structure also includes a pump light input port for connecting an external pump light source. The gain module needs to be set at a position close to the pump light input port, so as to reduce the transmission loss of the pump light in the optical waveguide structure.

[0012] In an optional embodiment, the optical waveguide structure is connected to other optical devices through optical fibers, and the pump light and the optical signal are both transmitted into the optical waveguide structure through the input optical fiber. Therefore, the pump light input port is the optical fiber input port connected to the input optical fiber, and the optical fiber input port is set at one end of the passive waveguide, that is, the gain module needs to be set near this end.

[0013] In an optional embodiment, the optical waveguide structure provides a plurality of chip insertion ports for connecting a plurality of optical chips. The pump laser chip is connected to the optical waveguide structure through the pump laser chip insertion port to provide pump light for the gain module. Therefore, the gain module needs to be arranged near the pump laser chip insertion port.

[0014] In an alternative embodiment, the waveguide may be embedded in the substrate or in the glass cladding.

[0015] In a second aspect, an embodiment of the present application provides a method for preparing an optical waveguide structure, the method comprising:

[0016] First, a waveguide is formed based on a substrate, and then a gain module in contact with the waveguide is formed. The waveguide is used to transmit optical signals, and the gain module is used to compensate and amplify the optical signals in the waveguide. Therefore, the refractive index of the gain module is close to that of the waveguide, and the gain module is in contact with the waveguide. In this way, the optical signal in the waveguide can be transmitted to the gain module, and then transmitted back to the waveguide after being amplified by the gain module. Then, a cladding is formed, and the cladding and the substrate together wrap the waveguide and the gain module, and the refractive index of the waveguide and the gain module is greater than the refractive index of the substrate and the cladding.

[0017] The new optical waveguide structure formed by this method has the waveguide for optical signal transmission and the gain module for amplifying the optical signal integrated in the optical waveguide structure. In this way, during the transmission of the optical signal, the gain module can directly compensate for the transmission loss of the optical signal without the need for an independent amplifier as a relay to amplify the optical signal. In this way, the coupling and mounting of the waveguide and the independent amplifying element are avoided, and there is no need to integrate the waveguide and the independent amplifying element. This greatly reduces the complexity of the system-level packaging and improves the integration of the entire optical system.

[0018] In an optional embodiment, a portion of the substrate may be made into a waveguide. First, a metal mask may be formed on the substrate. Then, a first hollow portion is formed on the metal mask, and then, under the protection of the metal mask, the portion of the substrate exposed by the first hollow portion is made into a waveguide. Specifically, the refractive index of the exposed portion of the substrate needs to be changed to form a waveguide, and finally the metal mask is removed.

[0019] In an optional embodiment, when forming the gain module, a protective layer may be first formed on the substrate on which the waveguide is formed, and then a second hollow portion may be formed on the protective layer. Then, under the protection of the protective layer, the substrate exposed at the second hollow portion is thinned to form a first groove, so that the first groove exposes a portion of the waveguide. Then, a gain module doped with gain ions needs to be formed in the first groove to ensure that the gain module is in contact with the waveguide.

[0020] In an optional implementation, the first waveguide may be formed by deposition. Specifically, a first cladding layer is first formed on the substrate, a waveguide layer is then deposited on the side of the first cladding layer away from the glass substrate, and then the waveguide layer is etched to form the waveguide.

[0021] In an optional embodiment, after the waveguide is formed by deposition, a second cladding layer needs to be formed on the substrate so that the second cladding layer wraps around the waveguide. Then, at least one second groove is formed on the side of the second cladding layer away from the waveguide to expose a part of the structure of the waveguide. Then, a gain module is formed in the second groove. Finally, a third cladding layer is formed on the gain module.

[0022] In a third aspect, an embodiment of the present application provides an insertion board, which includes an optical waveguide structure provided in any possible implementation manner as described above, wherein the insertion board is used to connect a plurality of optoelectronic chips.

[0023] In a fourth aspect, an embodiment of the present application provides an optical backplane, which includes an optical waveguide structure provided in any possible implementation method as described above, wherein an insertion board is used to connect multiple adapter boards. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the structure of an insert plate shown in an embodiment of the present application;

[0025] Figure 2 A schematic diagram of the structure of an optical backplane shown in an embodiment of the present application;

[0026] Figure 3 A schematic diagram of the structure of an optical waveguide structure shown in an embodiment of the present application;

[0027] Figure 4A for Figure 3 Schematic diagram of the cross section in the YZ direction;

[0028] Figure 4B for Figure 3 Schematic diagram of the cross section in the XZ direction.

[0029] Figure 4C for Figure 4B Light path diagram of the optical signal in;

[0030] Figure 4D A schematic cross-sectional view of another optical waveguide structure provided in an embodiment of the present application in the YZ direction;

[0031] Figure 4E A schematic cross-sectional view of another optical waveguide structure provided in an embodiment of the present application in the XZ direction;

[0032] Figure 5A A schematic cross-sectional view of another optical waveguide structure provided in an embodiment of the present application in the XZ direction;

[0033] Figure 5B A schematic cross-sectional view of another optical waveguide structure provided in an embodiment of the present application in the XZ direction;

[0034] Fig. 6A A schematic cross-sectional view of another optical waveguide structure provided in an embodiment of the present application in the YZ direction;

[0035] Figure 6B A schematic cross-sectional view of another optical waveguide structure provided in an embodiment of the present application in the YZ direction;

[0036] Figure 7 A schematic diagram of a process for preparing an optical waveguide structure provided in an embodiment of the present application;

[0037] FIG8 is a schematic diagram of an optical waveguide structure provided in an embodiment of the present application during the manufacturing process;

[0038] Fig. 8A A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0039] Figure 8B A schematic diagram of an optical waveguide structure provided in an embodiment of the present application during the manufacturing process

[0040] Figure 8C A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0041] Fig.8D A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0042] Fig. 9A A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0043] Fig. 9B A schematic diagram of a waveguide structure provided in an embodiment of the present application during the manufacturing process;

[0044] Fig. 10AA schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0045] Fig. 10B A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0046] Fig.11A A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0047] Fig. 11B A schematic diagram of an optical waveguide structure during the manufacturing process provided in an embodiment of the present application;

[0048] Fig. 11C A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0049] Fig.11D A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0050] Fig.11E A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0051] Fig.11F A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0052] Fig.11G A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0053] Fig.12 A schematic flow chart of another method for preparing an optical waveguide structure provided in an embodiment of the present application;

[0054] Fig.13 A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0055] Fig.14 A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0056] Fig.15A A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0057] Fig. 15B A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0058] Fig.16 A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0059] Fig.17A A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0060] Fig. 17B A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0061] Fig.18 A schematic diagram of an optical waveguide structure during the manufacturing process provided by an embodiment of the present application;

[0062] Fig.19 A schematic diagram of an optical waveguide structure during the manufacturing process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] The embodiment of the present application provides an optical waveguide structure and a method for preparing the optical waveguide structure. In the process of preparing the optical waveguide structure, a waveguide for optical signal transmission and a gain module for optical signal amplification are integrated, thus avoiding the coupling and mounting of the waveguide with other independent amplifying elements, thereby greatly reducing the complexity of the system-level packaging and improving the integration of the entire optical system.

[0064] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0065] The terms "first", "second", etc. in the specification embodiments, claims and drawings of the present application are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one (item)" means one or more, and "multiple" means two or more. "Installation", "connection", "connected", etc. should be understood in a broad sense, for example, it can be an electrical connection or a mechanical connection; it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or it can be indirect through an intermediate medium, or it can be the internal connection of two elements. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, including a series of steps or units. Methods, systems, products or devices are not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices. "Up", "down", "left", "right", etc. are only used relative to the orientation of the components in the drawings. These directional terms are relative concepts. They are used for description and clarification relative to the description, which may change accordingly according to the change of the orientation of the components in the drawings.

[0066] The present application embodiment provides an insert board, which is applied to the field of optoelectronic integration. Figure 1 As shown, the insertion board includes an optical waveguide structure and multiple optoelectronic chip insertion ports arranged on the optical waveguide structure. Multiple optoelectronic chips are connected to the waveguide in the optical waveguide structure through the optoelectronic chip insertion ports to achieve interconnection of multiple optoelectronic chips. Among them, the waveguide in the optical waveguide structure is a transmission channel for optical signals. For example, Figure 1 In the embodiment, chip 1 and chip 2 are inserted into the optical waveguide structure of the insertion board through the optoelectronic chip insertion port. Chip 1 includes a transmitting module, and chip 2 includes a receiving module. When chip 1 and chip 2 communicate, the transmitting module of chip 1 sends an optical signal to the waveguide of the optical waveguide structure, and the optical signal is transmitted along the waveguide to the receiving module of chip 2 to complete the optical communication.

[0067] With the development of System in Pack (SiP), the complexity of chip packaging and the bandwidth between chips are getting higher and higher, which puts higher requirements on the insertion board used to connect multiple chips. For example, as the scale of optoelectronic integrated systems becomes larger and larger, the number of optoelectronic chips that need to be coupled and integrated will also increase. The size of the insertion board, as a device that connects the circuit substrate and provides a waveguide channel for optical communication between chips, will also become larger and larger. For large-sized insertion boards, the transmission loss of optical signals between boards must be considered. In an embodiment of the present application, the optical waveguide structure in the insertion board no longer simply includes only waveguides, but integrates waveguides and gain modules. Among them, the gain module can be a small section of active waveguide doped with gain ions, such as Er ions. In this way, the optical signal is transmitted in the waveguide, and when it passes through the gain module, it will be transmitted to the gain module, and after amplification by the gain module, it will be transmitted back to the waveguide for continued transmission, so that the loss of the optical signal can be compensated.

[0068] This new optical waveguide structure design can use the gain module to directly amplify the optical signal during the optical signal transmission process, without the need for independent amplifier components to amplify the optical signal as a relay. In this way, there is no need to integrate the waveguide and amplifier components, which greatly reduces the complexity of the system-level packaging and improves the integration of the entire system.

[0069] The present application also provides an optical backplane suitable for data center scenarios. Figure 2 As shown, the optical backplane is used to connect multiple adapter boards to achieve interconnection between multiple adapter boards. In order to improve the communication rate between multiple adapter boards, the optical backplane can be used to replace the original optical fiber connection. The adapter board is inserted into the optical backplane, and the waveguide of the optical backplane provides it with an optical signal transmission channel. In this way, the integration of the entire system is greatly improved. The optical backplanes are connected to each other through optical fibers.

[0070] Similarly, as the number of adapter boards increases, the size of the optical backplane will become very large, and for large-sized access boards, the loss of optical signals during transmission between boards must be considered. In an embodiment of the present application, the optical waveguide structure in the optical backplane no longer simply includes only waveguides. Instead, the waveguide is covered with a gain module, which can be a small section of active waveguide doped with gain ions. In this way, when the optical signal is transmitted in the waveguide, the gain module will amplify the optical signal, and then transmit the amplified optical signal back to the waveguide for continued transmission, so that the loss of the optical signal can be compensated. In this way, there is no need to integrate waveguides and amplifier components, which greatly reduces the complexity of system-level packaging and improves the integration of the entire system.

[0071] It is understandable that the optical waveguide structure with a gain module can be used not only in optical backplanes in the communication field and optoelectronic integrated insertion boards, but also in other fields that require optical signal amplification, such as the sensing field. The optical waveguide structure can amplify and transmit the sensing optical signal in the on-chip integration. Compared with the optical band around 1550nm that is mostly used in the communication field, the wavelength of light required to be amplified for sensing needs to be changed according to the specific application, and will mainly be further expanded to the infrared band. Therefore, the gain ions doped in the gain module may be different, and the size of the gain module will also be slightly different. This application does not impose any restrictions on this.

[0072] The optical waveguide structure provided in the embodiments of the present application is described in detail below.

[0073] Figure 3 This is a schematic diagram of the structure of an optical waveguide structure shown in an embodiment of the present application. Figure 4A for Figure 3 Schematic diagram of the cross section in the YZ direction, Figure 4B for Figure 3 Schematic diagram of the cross section in the XZ direction.

[0074] Schematically, the present application embodiment provides an optical waveguide structure, referring to Figure 3 and Figure 4A As shown, the optical waveguide structure includes a substrate 10, a waveguide 20, a gain module 30 and a cladding 40 from bottom to top. The waveguide 20 and the gain module 30 are located between the substrate 10 and the cladding 40. The gain module is located at the upper end of the waveguide 20 and is in contact with the waveguide 20. The waveguide 20 and the gain module 30 together constitute the core layer of the optical waveguide structure. The substrate 10 and the cladding 40 wrap the waveguide 20 and the gain module 30 to form the cladding of the optical waveguide structure.

[0075] Indicative, reference Figure 4A and Figure 4B As shown, the waveguide 20 may be a passive waveguide extending along the X direction, and its cross section may be circular, so that the optical transmission mode field of the waveguide will approach circular symmetry, further reducing the transmission loss of the optical signal.

[0076] Indicative, reference Figure 4A and Figure 4B As shown, the gain module 30 is an active waveguide doped with gain ions that contacts the axial surface of the waveguide 20. The waveguide 20 is a transmission channel for the optical signal, and the gain module 30 is used to amplify the optical signal being transmitted. Specifically, the optical signal is transmitted through the waveguide 20, and after encountering the gain module 30, it is transmitted to the gain module 30 for amplification, and then transmitted back from the gain module 30 to the waveguide 20 for continued transmission, thereby compensating for the loss of the optical signal during the transmission process.

[0077] The following describes in detail how the waveguide 20 transmits the optical signal and how the gain module 30 amplifies the optical signal:

[0078] As shown, the waveguide 20, the gain module 30, the substrate 10 and the cladding 40 are all made of light-transmitting materials, and the refractive indexes of the waveguide 20 and the gain module 30 are close and both greater than those of the substrate 10 and the cladding 40. Thus, when an optical signal that meets the incident angle condition is transmitted through the transmission port of the optical waveguide structure, it will be totally reflected in the waveguide 20, and thus will be confined to be transmitted in the waveguide 20, and will not be transmitted to the substrate 10 and the cladding 40. When the optical signal is transmitted along the waveguide 20, when it encounters the gain module 30, since the refractive indexes of the waveguide 20 and the gain module 30 are close, it will be transmitted from the waveguide 20 to the gain module 30, and then be totally reflected in the gain module 30 and transmitted into the waveguide 20. Figure 4C As shown, the optical path diagram of the optical signal in the optical waveguide structure is shown.

[0079] As shown, when the optical signal is transmitted in the gain module 30, it will be amplified. This is because the gain module 30 is doped with gain ions compared to the passive waveguide 20. Among them, the gain ions can be erbium Er ions, which can achieve the amplification of optical signals in the optical band near 1550nm. The amplification principle is that after the rare earth element Er absorbs the pump light energy of the appropriate wavelength, the electrons will transition from the ground state to the excited state with a high energy level, and the electrons of the Er ions will undergo a huge inversion, that is, the number of metastable electrons in the high energy level is greater than the number of baseband electrons in the low energy level. At this time, when the optical signal passes through, the metastable electrons will undergo stimulated radiation effect, emitting a large number of photons of the same wavelength to amplify the optical signal. It can be understood that when the optical signal is a signal of other bands, the gain ions may be extended to rare earth ions such as Ho, Pr, Tm, Yb and their combinations, and this application does not limit this.

[0080] For illustration, the location of the gain module 30 is not limited. Figure 4B As shown, the gain module can be arranged on the upper side of the waveguide 20. Figure 4D As shown, the gain module can also be arranged on the left and right sides of the waveguide 20. Figure 4E As shown, the gain module 30 may also be disposed at both ends of the waveguide 20 , that is, the gain module 30 is in contact with the circumferential surface of the waveguide 20 , which is not specifically limited.

[0081] Indicatively, refer to Figure 4B As shown, when the optical waveguide structure includes a plurality of gain modules 30 , they may be sequentially spaced apart on a side away from the substrate, and each gain module 30 is in contact with the axial surface of the waveguide 20 .

[0082] It can be seen from the above description that in the design of this novel optical waveguide structure, the waveguide 20 for optical signal transmission and the gain module 30 for amplifying the optical signal are all integrated in the optical waveguide structure. In this way, during the transmission of the optical signal, the gain module 30 can directly compensate for the transmission loss of the optical signal without the need for an independent amplifier to amplify the optical signal. In this way, the coupling and mounting of the waveguide and the independent amplifying element are avoided, and there is no need to integrate the waveguide and the independent amplifying element. This greatly reduces the complexity of the system-level packaging and improves the integration of the entire optical system.

[0083] From the above description, it can be seen that the gain module 30 needs to absorb the pump light first to amplify the optical signal, and wait for the gain ions to transition to the excited state before amplifying the optical signal passing through. Therefore, the optical waveguide structure needs to be connected to the pump light source. Therefore, it is necessary to set a pump light input port on the optical waveguide structure, and in order to reduce the transmission loss of the pump light in the optical waveguide structure, the gain module 30 needs to be set at a position close to the pump light input port.

[0084] Indicative, reference Figure 5A As shown, if the optical waveguide structure is used as an insertion plate to connect multiple optoelectronic chips, multiple chip insertion ports 410 will be set on the side away from the substrate 10. Multiple optoelectronic chips are inserted into the optical waveguide structure through the chip insertion port 410 and connected through the waveguide 20 to achieve interconnection. In this scenario, the pump light required by the gain module 30 will be provided by the pump laser chip, that is, the chip insertion port 410 includes a pump laser chip insertion port 4101. At this time, in order to reduce light loss, the gain module 30 needs to be set near the pump laser chip insertion port 4101.

[0085] Indicative, reference Figure 5B As shown, the optical waveguide structure is connected to other optical devices through optical fibers. Therefore, the optical waveguide structure is provided with an optical fiber input port 2101, which is arranged at the top of the waveguide 20, and the external input optical fiber is connected to the waveguide 20 through the optical fiber input port 2101. Similarly, the optical waveguide structure will also be provided with an optical fiber output port 2102, which is arranged at the end of the waveguide 20, and the external output optical fiber is connected to the waveguide 20 through the optical fiber output port 2102.

[0086] In this scenario, the pump light and the optical signal to be transmitted are transmitted to the optical fiber input port 2101 through the input optical fiber, then transmitted to the waveguide 20, and then transmitted to the gain module 30 through the waveguide 20. In order to reduce optical loss, the gain module 30 needs to be arranged near the optical fiber input port 2101, that is, in the horizontal direction, the distance from the gain module 30 to the optical fiber input port 2101 is shorter than the distance from the gain module 30 to the optical fiber output port 2102.

[0087] Several structural deformations of optical waveguide structures are introduced below:

[0088] Indicative, reference Figure 4A As shown in FIG. 1 , the waveguide 20 is embedded in the substrate 10, so that the loss of the waveguide 20 is low. A groove 101 is provided in the substrate 20 at the upper end of the waveguide 20, and the bottom of the groove 101 exposes a portion of the waveguide 20. The gain module 30 is embedded in the groove 101 and contacts the exposed portion of the waveguide 20. The cladding 40 covers the gain module 30, and the waveguide 20 and the gain module 30 are wrapped between the cladding 40 and the substrate 10.

[0089] The cross section of the waveguide 20 in the YZ direction may be circular, so that the light transmission mode field of the waveguide 20 will tend to be circularly symmetric, which can reduce signal transmission loss. The cross section of the gain module 30 in the YZ direction may be rectangular.

[0090] Indicative, reference Fig. 6A As shown, the waveguide 20 is embedded in the substrate 10, but the waveguide 20 is flush with the surface of the substrate 10. The gain module 30 is located at the upper end of the substrate 10 and is not embedded in the substrate 10. The gain module 30 is still in contact with part of the waveguide 20, and the cladding 40 covers the gain module 30, wrapping the waveguide 20 and the gain module 30 between the cladding 40 and the substrate 10.

[0091] Indicative, reference Figure 6B As shown, the waveguide 20 and the gain module 30 are not embedded in the substrate 10, but are completely wrapped by the cladding 40 located on the upper end of the substrate 10. The waveguide 20 and the gain module 30 are both embedded in the cladding 40, the waveguide 20 penetrates the cladding 40, and the gain module 30 contacts part of the waveguide 20. The cross-section of the waveguide 20 in the YZ direction can be a rectangular shape. The cross-section of the gain module 30 in the YZ direction can also be a rectangular shape.

[0092] In an illustrative embodiment, the present application also provides a method for manufacturing the aforementioned optical waveguide structure, such as Figure 7 As shown, the production method may include:

[0093] 701. Make a portion of the substrate 10 into a waveguide 20.

[0094] In the embodiment of the present application, the refractive index of a part of the structure of the substrate 10 can be changed by an ion exchange method, thereby forming a waveguide 20. The specific manufacturing process is as follows:

[0095] It is necessary to form a metal mask 50 on the substrate 10 first.

[0096] Indicative, reference Fig. 8A As shown, a thin borosilicate glass plate made by overflow down-drawing method can be selected as the substrate 10. Figure 8B As shown, a metal film 60 with a thickness of 100 nanometers is plated on the substrate 10. Next, referring to Figure 8C As shown, a layer of photoresist 70 is uniformly coated on the metal film 60. The photoresist 70 is used to define the optical waveguide distribution design pattern by laser direct writing or proximity exposure to form a hollow area 701. Then, refer to Fig.8D As shown, under the protection of the photoresist 70, the metal film 60 is etched to form a metal mask 50 and then the photoresist 70 is removed. The metal mask 50 includes a first hollow portion 501, which can be formed along the Figure 3 The X direction shown runs through the entire metal mask 50 . It can be understood that the first hollow portion 50 opens the ion exchange channel of the substrate 10 .

[0097] Next, the substrate 10 needs to be placed in a salt solution.

[0098] As shown, the substrate 10 with the metal mask 50 needs to be placed in a nitrate solution, and then ion exchange is performed for several hours at 290-400°C. The area of ​​the substrate 10 protected by the metal mask 50 cannot undergo ion exchange, while the first hollow portion 501 in the metal mask 50 exposes part of the substrate 10, and the Ag+ / K+ ions in the salt solution can be exchanged with the Na+ ions in the substrate 10 through the first hollow portion 501. Fig. 9A As shown in FIG. 1 , after ion exchange, the refractive index of a portion of the substrate 10 changes, forming a surface waveguide 20. Fig. 9B As shown, the waveguide 20 runs through the entire substrate 10 along the X direction. The refractive index of the first waveguide 10 is greater than that of other regions of the substrate 10 that are not waveguides. In this way, the optical signal that meets the incident angle condition will be confined to the waveguide 20 for transmission, and will not be transmitted to other regions of the substrate 10.

[0099] As shown in FIG. 1 , the waveguide 20 located on the surface of the substrate 10 may also be buried in the substrate 10 . Fig. 10A As shown, in the formation of Fig. 9A After the waveguide 10 is formed, the metal mask 50 on the surface of the substrate 10 is removed. Fig. 10A The substrate 10 shown is placed in a nitrate solution, and the Ag+ / Na+ ion distribution in the substrate 10 is adjusted by applying voltage or secondary heat exchange to adjust the position of the waveguide 20. Fig. 10B As shown, the waveguide 20 is buried to the preset thickness of the substrate 10 and embedded in the substrate 10, and the cross section of the waveguide 20 in the YZ direction is closer to a circle. In this way, the optical transmission mode field of the waveguide 20 is closer to circular symmetry, and the waveguide 20 is also wrapped more tightly, so when transmitting optical signals, the transmission loss will become lower.

[0100] 702 . Form a gain module 30 in contact with the waveguide 20 .

[0101] Among them, the gain module 30 can be a small section of active waveguide doped with gain ions. The gain ions can be erbium Er ions to achieve the amplification of optical signals in the optical band near 1550nm. The amplification principle is that after the rare earth element Er absorbs the pump light energy of the appropriate wavelength, the electrons will transition from the ground state to the excited state with a high energy level. At this time, when the light signal passes through, the excited state electrons will undergo stimulated radiation effect and emit a large number of photons of the same wavelength to amplify the light signal. It can be understood that the type of gain ions can be specifically determined according to the wavelength band of the light signal, and this application does not limit this.

[0102] When forming the gain module 30 , a protection layer 1001 is first formed on the substrate.

[0103] refer to Fig.11A As shown, you can first Fig. 10B A protective layer 1001 is formed on the substrate 10 shown. Exemplarily, the protective layer 1001 may be a photoresist. Then, at least one second hollow portion 1002 is formed on the protective layer 1001. The second hollow portion 1002 is formed by photolithography technology, and its size can be adjusted according to the subsequent gain of the rare earth doped glass and the required gain. Fig. 11B As shown, one second hollow portion 1002 may be formed, or a plurality of second hollow portions 1002 may be formed. When a plurality of second hollow portions 1002 are formed, the second hollow portions 1002 are sequentially arranged at intervals in the X direction.

[0104] Next, under the protection of the protective layer 1001, the substrate 10 exposed by the second hollow portion 1002 is thinned by plasma thinning, and then the protective layer 1001 is removed. Fig. 11C As shown, a first groove 101 is formed on the substrate 10, and the depth of the first groove 101 is equal to the embedding depth of the waveguide 20. The first groove 101 can expose a part of the structure of the waveguide 20. In this way, the gain module 30 in the first groove 101 can contact a part of the structure of the waveguide 20.

[0105] It can be understood that thinning the substrate 10 by plasma thinning can not only form the first groove 101, but also polish the inner wall of the first groove 101 and reduce the roughness of the inner wall, which can effectively reduce the optical signal transmission loss of the subsequently deposited gain module.

[0106] Then, the gain module 30 is formed in the first groove 101 .

[0107] Indicative, such as Fig.11D As shown, a 6 μm thick Er3+-doped silicate glass can be deposited in the first groove 101 using a plasma enhanced chemical vapor deposition (PECVD) or flame hydrolysis deposition (FHD) process to form a gain module 30. As shown in reference 11E, the gain module 30 is in contact with a portion of the structure of the waveguide 20. Among them, the composition of the silicate glass needs to be adjusted so that the refractive index of the gain module 30 is approximately consistent with the refractive index of the waveguide 20. In this way, the optical signal transmitted in the waveguide 20 can be transmitted to the gain module 30, and then the gain module 30 amplifies the optical signal and transmits it back to the waveguide 20.

[0108] 703 . Form a cladding 40 on the waveguide 20 and the gain module 30 .

[0109] refer to Fig.11F and Fig.11G After forming the gain module 30, a 20-30 μm thick borosilicate glass is deposited on the gain module 30 using a PECVD or FHD process to form a cladding 40. The cladding 40 and the substrate 10 wrap the waveguide 20 and the gain module 30, and the glass composition and refractive index of the cladding 40 are similar to those of the non-waveguide region of the substrate 10.

[0110] The method for preparing the optical waveguide structure provided in the embodiment of the present application, when preparing the waveguide 20 for optical signal transmission, simultaneously prepares the gain module 30 for amplifying the optical signal. In this way, the waveguide 20 and the gain module 30 are all integrated in the optical waveguide structure. During the transmission of the optical signal, the gain module 30 can directly compensate for the transmission loss of the optical signal without the need for an independent amplifier as a relay to amplify the optical signal. In this way, the coupling and mounting of the waveguide and the independent amplifying element are avoided, and there is no need to integrate the waveguide and the independent amplifying element. This greatly reduces the complexity of the system-level packaging and improves the integration of the entire optical system.

[0111] As an illustration, the present application also provides another method for manufacturing the aforementioned optical waveguide structure, such as Fig.12 As shown, the production method may include:

[0112] 1201 . Form a first cladding layer 401 on the substrate 10 .

[0113] First, refer to Fig.13 As shown, a fused silica glass with a thickness of 500 μm-1000 μm can be selected as the substrate 10, and then a fused silica cladding layer, namely the first cladding layer 401, is deposited thereon by using a PECVD / FHD process.

[0114] 1202 . Form a waveguide layer 201 on the first cladding layer 401 .

[0115] Next, refer to Fig.14 As shown, a layer of Ge-doped fused silica glass with a thickness of 5 μm-9 μm is deposited on the first cladding layer 401 to form a waveguide layer 201. It can be understood that the refractive index of the waveguide layer 201 will be greater than that of the first cladding layer 401. In this way, the optical signal that meets the incident angle condition can be limited to be transmitted in this layer.

[0116] 1203 . Etch the waveguide layer 201 to form a waveguide 20 .

[0117] refer to Fig.15A and Fig. 15B As shown, a protective layer 2013 may be formed on the waveguide layer 201 , and under the protection of the protective layer 2013 , the waveguide layer 201 is etched to form the waveguide 20 .

[0118] 1204 . Form a second cladding layer 402 on the waveguide 20 .

[0119] refer to Fig.16 As shown, a second cladding layer 402 is deposited on the waveguide 20 to wrap the waveguide 20. The second cladding layer 402 has the same composition and refractive index as the first cladding layer 401, which will not be described in detail.

[0120] 1205 . Form at least one fourth groove 4021 on a side of the second cladding layer 402 facing away from the waveguide 20 .

[0121] refer to Fig.17A and Fig. 17B As shown, a fourth groove 4021 needs to be formed in the second cladding layer 402. Similarly, a protective layer 4022 can be formed on the second cladding layer 402, and the protective layer 4022 can be a photoresist. The protective layer 4022 has a third hollow portion 4023. Under the protection of the protective layer 4022, the second cladding layer 402 is etched to form a fourth groove 4021. The bottom of the fourth groove 4021 will expose a portion of the waveguide 20.

[0122] 1206 . Form a gain module 30 in the fourth groove 4021 .

[0123] Indicative, such as Fig.18 As shown, a 6 μm thick Er3+-doped silicate glass can be deposited in the fourth groove 4021 using a plasma enhanced chemical vapor deposition (PECVD) or flame hydrolysis deposition (FHD) process to form a gain module 30. The gain module 30 is in contact with a portion of the structure of the waveguide 20. At the same time, the composition of the silicate glass needs to be adjusted so that the refractive index of the gain module 30 is approximately consistent with the refractive index of the waveguide 20. In this way, the optical signal transmitted in the waveguide 20 can be transmitted to the gain module 30, and then the gain module 30 amplifies the optical signal and transmits it back to the waveguide 20.

[0124] 1207 . Form a third cladding layer 403 on the gain module 30 .

[0125] refer to Fig.19 After forming the gain module 30, it is necessary to use a PECVD or FHD process to deposit fused silica glass on the gain module 30 to form a third cladding 403. The first cladding 401, the second cladding 402 and the third cladding 403 wrap the waveguide 20 and the gain module 30.

[0126] The method for preparing the optical waveguide structure provided in the embodiment of the present application, when preparing the waveguide 20 for optical signal transmission, simultaneously prepares the gain module 30 for amplifying the optical signal. In this way, the waveguide 20 and the gain module 30 are all integrated in the optical waveguide structure. During the transmission of the optical signal, the gain module 30 can directly compensate for the transmission loss of the optical signal without the need for an independent amplifier as a relay to amplify the optical signal. In this way, the coupling and mounting of the waveguide and the independent amplifying element are avoided, and there is no need to integrate the waveguide and the independent amplifying element. This greatly reduces the complexity of the system-level packaging and improves the integration of the entire optical system.

[0127] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0128] For other related contents in the above-mentioned manufacturing method, you can refer to the corresponding parts in the above-mentioned chip structure embodiment, which will not be repeated here; for other setting structures in the above-mentioned chip structure embodiment, you can refer to the above-mentioned manufacturing method and related manufacturing methods for adjustment, which will not be repeated here one by one.

[0129] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An optical waveguide structure, characterized in that: The optical waveguide structure comprises: substrates, waveguides, gain blocks, and cladding; The waveguide and the gain module are located between the substrate and the cladding; the waveguide and the gain module have the same refractive index, and the refractive index of the waveguide and the gain module is greater than the refractive index of the substrate and the cladding; The gain module is in contact with the waveguide; wherein the waveguide is used to transmit an optical signal, and the gain module is used to amplify the optical signal.

2. The optical waveguide structure according to claim 1, characterized in that: The waveguide is a passive waveguide; the gain module includes an active waveguide doped with gain ions; and the length of the passive waveguide is greater than the length of the active waveguide.

3. The optical waveguide structure according to any one of claims 1 to 2, characterized in that: The cross section of the waveguide is circular; the gain module is in contact with a circumferential surface or an axial surface of the waveguide.

4. The optical waveguide structure according to any one of claims 1 to 3, characterized in that: The optical waveguide structure includes a plurality of gain modules; The plurality of gain modules are arranged at intervals along the extending direction of the waveguide on a side of the waveguide away from the substrate, and are all in contact with the waveguide.

5. The optical waveguide structure according to any one of claims 1 to 4, characterized in that: The optical waveguide structure comprises a pump light input port; the gain module is arranged near the pump light input port.

6. The optical waveguide structure according to claim 5, characterized in that: The pump light input port is an optical fiber input port; the optical fiber input port is located at one end of the waveguide.

7. The optical waveguide structure according to claim 5, characterized in that: The pump light input port is a pump laser chip insertion port, and the pump laser chip insertion port is arranged on a side of the waveguide away from the substrate.

8. The optical waveguide structure according to any one of claims 1 to 7, characterized in that: The waveguide is embedded in the substrate, or the waveguide is embedded in the cladding.

9. A method for preparing an optical waveguide structure, characterized in that: The method comprises: forming a waveguide based on the substrate; forming a gain module in contact with the waveguide; wherein the gain module is used to amplify the optical signal; the waveguide and the gain module have the same refractive index, and the refractive index of the waveguide and the gain module is greater than the refractive index of the substrate; A cladding is formed on the waveguide and the gain module; wherein the refractive index of the waveguide and the gain module is greater than the refractive index of the cladding.

10. The preparation method according to claim 9, characterized in that: The method of forming a waveguide based on a substrate comprises: forming a metal mask on the substrate; Etching the metal mask to form a first hollow portion on the metal mask; forming a portion of the substrate exposed by the first hollow portion into the waveguide; The metal mask is removed.

11. The preparation method according to claim 10, characterized in that: The forming of a gain module in contact with the waveguide comprises: forming a protective layer on the substrate; forming at least one second hollow portion on the protective layer; Performing a thinning process on the substrate exposed at the second hollow portion to form a first groove; The gain module is formed in the first groove; wherein the material of the gain module is doped with gain ions.

12. The preparation method according to claim 9, characterized in that: The forming of a first waveguide based on a substrate comprises: forming a first cladding layer on the substrate; forming a waveguide layer on a side of the first cladding layer facing away from the substrate; The waveguide layer is etched to form the waveguide.

13. The preparation method according to claim 12, characterized in that: The forming of a gain module in contact with the waveguide comprises: forming a second cladding layer on the substrate so that the waveguide is completely embedded in the second cladding layer; forming at least one second groove on a side of the second cladding layer facing away from the first waveguide, wherein a bottom of the second groove exposes a portion of the waveguide; forming the gain module in the second groove; The forming of a cladding layer on the waveguide and the gain module comprises: A third cladding layer is formed on the gain module.

14. An insert plate, characterized in that: The insert board comprises the optical waveguide structure according to any one of claims 1 to 8, and the insert board is used to connect a plurality of optoelectronic chips.

15. An optical backplane, characterized in that: The optical backplane comprises the optical waveguide structure according to any one of claims 1 to 8, and the optical backplane is used to connect a plurality of adapter plates.

Images