Optical transmitting component, optical receiving component and optical module

Abstract

The application discloses an optical transmitting assembly, an optical receiving assembly and an optical module, wherein the optical transmitting assembly comprises a laser, a first optical chip, a second mode spot converter and a first optical fiber; the first optical chip comprises an optical multiplexer and a mode spot converter; the laser is used for generating laser; the optical multiplexer is used for multiplexing the laser; the first mode spot converter is used for amplifying the mode spot of the outgoing light of the optical multiplexer; and the second mode spot converter is used for amplifying the mode spot of the outgoing light of the first mode spot converter. In the optical transmitting assembly, the optical receiving assembly and the optical module, the mode spot conversion is performed by two mode spot converters on the optical chip and outside the optical chip respectively, the demand for the overall coupling capacity of the mode spot converter on the chip is reduced, the mode spot converter on the chip only needs to have high coupling efficiency for different polarization states, and the size of the mode spot can be adjusted appropriately, so that the polarization-dependent loss can be avoided while the coupling efficiency is met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical communication, and particularly relates to an optical transmitting assembly, an optical receiving assembly and an optical module. BACKGROUND

[0002] In the optical transmitting assembly of the optical module, a PBRC (polarization beam rotator combiner) is often introduced on the optical chip to complete the function of one-level multiplexing, at this time different polarization states are introduced. When the mode spot converter (usually realized by an edge coupler) on the optical chip is coupled with the optical fiber, due to the large mode spot size of the optical fiber, the mode spot converter often cannot guarantee that the mode spots of different polarization states have the same shape and size while guaranteeing the overall coupling efficiency, and cannot guarantee that different polarization states have the same or close coupling efficiency. When the input light has different polarization states, the difference in coupling efficiency between different polarization states will introduce polarization-dependent loss, causing unevenness between channels.

[0003] At the same time, for the optical chip in the optical receiving assembly, the signals received by the optical chip come from long-distance optical fiber transmission and have random polarization states. Similarly, when the on-chip mode spot converter is coupled and converted, polarization-dependent loss is introduced, causing unevenness of signals in the time domain and between channels. These problems need to be avoided in products.

[0004] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the background of the present application and should not be taken as an acknowledgment or any form of suggestion that this information forms prior art that is publicly known. SUMMARY

[0005] The present application aims to provide an optical transmitting assembly, an optical receiving assembly and an optical module, which can solve the problem that the coupling efficiency cannot be simultaneously satisfied and polarization-dependent loss is avoided in the coupling process of the optical chip and the optical fiber.

[0006] To achieve the above-mentioned purpose, the technical scheme provided by a specific embodiment of the present application is as follows:

[0007] An optical transmitting assembly, comprising a laser, a first optical chip and a first optical fiber, the first optical chip comprising an optical multiplexer, the laser being configured to generate laser light, the optical multiplexer being configured to multiplex the laser light, the first optical chip further comprising a first mode spot converter, a second mode spot converter being arranged between the first optical chip and the first optical fiber, the first mode spot converter being configured to amplify the mode spot of the light emitted by the optical multiplexer, and the second mode spot converter being configured to amplify the mode spot of the light emitted by the first mode spot converter.

[0008] In one or more embodiments of the present application, the first mode field converter has a difference between conversion efficiency of TE mode and TM mode for the exiting light of the optical multiplexer less than or equal to 10%; and / or

[0009] The first mode field converter has an ellipticity of TE mode mode field and an ellipticity of TM mode mode field less than or equal to 1.5 for the exiting light of the first mode field converter; and / or

[0010] The first mode field converter has a difference between diameters of TE mode mode field and TM mode mode field less than or equal to 1.5 for the exiting light of the first mode field converter .

[0011] In one or more embodiments of the present application, the first mode field converter comprises a first cladding and a first waveguide disposed in the first cladding and extending along a first direction, the first waveguide has a width gradually decreasing along the first direction and a height equal, and the first waveguide is circular or a regular polygon with an even number of sides near an end face of the second mode field converter.

[0012] In one or more embodiments of the present application, the first waveguide is square near the end face of the first mode field converter; and / or

[0013] The first cladding has a width equal to a height.

[0014] In one or more embodiments of the present application, the first mode field converter comprises a first cladding and a plurality of second waveguides disposed in the first cladding and extending along a first direction.

[0015] In one or more embodiments of the present application, the second mode field converter comprises a first lens, and the first lens has a positive focal power.

[0016] In one or more embodiments of the present application, the optical transmitting assembly further comprises a first optical isolator, and the second mode field converter and the first optical isolator are sequentially disposed between the first optical chip and the first optical fiber; and / or

[0017] The optical transmitting assembly further comprises at least one first optical isolator, and a plurality of second mode field converters are disposed between the first optical chip and the first optical fiber, and the first optical isolator is disposed between adjacent second mode field converters.

[0018] The optical receiving assembly includes a second optical chip and a second optical fiber, the second optical chip includes an optical-electricity converter, the second optical chip further includes a third mode spot converter, a fourth mode spot converter is arranged between the second optical chip and the second optical fiber, the fourth mode spot converter is used for reducing the mode spot of the outgoing light of the second optical fiber, the third mode spot converter is used for reducing the mode spot of the outgoing light of the fourth mode spot converter, and the optical-electricity converter is used for performing optical-electricity conversion on the outgoing light of the third mode spot converter.

[0019] In one or more embodiments of the present application, when the TE mode spot and the TM mode spot of the outgoing light of the fourth mode spot converter are both circular, the difference between the conversion efficiencies of the TE mode and the TM mode of the third mode spot converter is less than or equal to 5%; and / or

[0020] When the diameter of the TE mode spot and the diameter of the TM mode spot of the outgoing light of the fourth mode spot converter are the same, the difference between the conversion efficiencies of the TE mode and the TM mode of the third mode spot converter is less than or equal to 10%.

[0021] In one or more embodiments of the present application, the third mode spot converter includes a second cladding and a third waveguide arranged in the second cladding and extending along a second direction, the width of the third waveguide gradually decreases along the second direction and the height of the third waveguide is equal, and the end face of the third waveguide close to the fourth mode spot converter is circular or a regular polygon with an even number of sides.

[0022] In one or more embodiments of the present application, the end face of the third waveguide close to the fourth mode spot converter is a square; and / or

[0023] The width of the second cladding is equal to the height of the second cladding.

[0024] In one or more embodiments of the present application, the third mode spot converter includes a second cladding and a plurality of fourth waveguides arranged in the second cladding and extending along a second direction.

[0025] In one or more embodiments of the present application, the fourth mode spot converter includes a second lens, and the second lens has a positive focal length.

[0026] In one or more embodiments of the present application, the optical receiving assembly further includes a second optical isolator, and the fourth mode spot converter and the second optical isolator are sequentially arranged between the second optical chip and the second optical fiber; and / or

[0027] The light receiving assembly further comprises at least one second optical isolator, a plurality of fourth mode field transformers are arranged between the second optical chip and the second optical fiber, and the second optical isolator is arranged between adjacent fourth mode field transformers.

[0028] The optical module according to an embodiment of the present application comprises the optical transmitting assembly or the optical receiving assembly.

[0029] Compared with the prior art in which only one mode field transformation is performed by the mode field transformer on the chip, in the optical transmitting assembly, the optical receiving assembly and the optical module, the mode field transformation is performed by two mode field transformers on and off the optical chip, the demand for the overall coupling capacity of the mode field transformer on the chip is reduced, the mode field transformer on the chip only needs to have high coupling efficiency for different polarization states and can appropriately adjust the size of the mode field, so that the polarization-dependent loss can be avoided while the coupling efficiency is met, and the design difficulty of the mode field transformer on the chip is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0031] Figure 1 It is a structural schematic diagram of the mode field transformer on the optical chip in the prior art.

[0032] Figure 2 It is a structural schematic diagram of the optical transmitting assembly in an embodiment of the present application.

[0033] Figure 3 It is a mode field transformation schematic diagram of the optical transmitting assembly in an embodiment of the present application.

[0034] Figure 4 It is a three-view diagram of the first mode field transformer in an embodiment of the present application.

[0035] Figure 5 It is a three-view diagram of the first mode field transformer in another embodiment of the present application.

[0036] Figure 6 It is a three-view diagram of the first mode field transformer in another embodiment of the present application.

[0037] Figure 7 It is a partial structural schematic diagram of the optical transmitting assembly in an embodiment of the present application.

[0038] Figure 8Part structure diagram of the optical receiving assembly in another embodiment of the present application.

[0039] Figure 9 Structure diagram of the optical receiving assembly in an embodiment of the present application.

[0040] Figure 10 Mode spot conversion diagram of the optical receiving assembly in an embodiment of the present application.

[0041] Figure 11 Three-view diagram of the third mode spot converter in an embodiment of the present application.

[0042] Figure 12 Three-view diagram of the third mode spot converter in another embodiment of the present application.

[0043] Figure 13 Three-view diagram of the third mode spot converter in another embodiment of the present application.

[0044] Figure 14 Part structure diagram of the optical receiving assembly in an embodiment of the present application.

[0045] Figure 15 Part structure diagram of the optical receiving assembly in another embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to enable persons skilled in the art to better understand the technical solutions in the present disclosure, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only some of the embodiments of the present disclosure, but not all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by persons skilled in the art without creative work should fall within the protection scope of the present disclosure.

[0047] In the specification, “coupling” or “connecting” or “linked” includes both direct connection and indirect connection. Indirect connection is the connection through an intermediate medium, such as the connection through an electrically conductive medium, which can have a parasitic inductance or a parasitic capacitance; indirect connection can also include the connection through other active devices or passive devices on the basis of achieving the same or similar functional purposes, such as the connection through circuits or components such as switches, follower circuits, etc. In addition, in the present application, words such as “first”, “second”, etc. are mainly used to distinguish one technical feature from another technical feature, and do not necessarily require or imply a certain actual relationship, quantity or order between the technical features.

[0048] In the detailed description of the application, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration various embodiments by which the application can be practiced. It is to be understood that other embodiments can be utilized and structural or logical changes can be made without departing from the scope of the present application. The following detailed description, therefore, is not to be taken in a limiting sense, as the scope of the application is defined by the appended claims.

[0049] Various operations can be described as multiple discrete actions or operations in a monitory sequence, where the ordering of various operations can not be essential. Specifically, these operations can not be performed in the recited order. The described operations can be performed in different order in other embodiments.

[0050] For purposes of this application, the phrase "A and / or B" means (A), (B), or (A and B). For purposes of this application, the phrase "A, B, and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0051] Various components, devices, can be referred to in the singular or plural throughout this document, but this is merely for convenience and brevity, and any element referred to in the singular can include a plurality of such elements according to the teachings herein.

[0052] The specification describes using the phrases "in one embodiment" or "in other embodiments" or "in some embodiments", which can each refer to one or more of the same or different embodiments. Furthermore, the terms "comprising", "including", "having" and the like, as used with respect to embodiments of the present application, are synonymous.

[0053] In the prior art, in order to eliminate the influence of polarization-related loss as much as possible, the main means is to balance by sacrificing the performance of the better polarization state. The TE polarization state of the general mode spot converter is easier to obtain better performance, while the TM polarization state is relatively poor compared to TE, typically about 0.8 dB. The existing design idea is generally to sacrifice the coupling efficiency of the TE mode to achieve balance with TM, but this sacrifices the performance of the optical module.

[0054] In Figure 1The diagram illustrates a design scheme in the prior art. This mode converter includes a cladding 10' and one (or more) inverted taper waveguides 20' disposed within the cladding 10'. Near the right side of the fiber, the heights H1' of the cladding 10' and H2' of the waveguide 20' are often determined by the SOI wafer or fab process and cannot be arbitrarily changed. To match the emitted light mode field as closely as possible to the fiber mode field, under current process conditions, only the width W2' of the waveguide 20' can be compressed; the width W1' of the cladding 10' is typically extended indefinitely, and the dimensions at the end of the waveguide 20' cannot be arbitrarily modified. Typically, the typical values ​​for these dimensions are W2' = 100 nm ~ 150 nm, H1' = 300 nm ~ 400 nm, and W1' = 100 nm ~ 150 nm. 9 H1'=6 ~9 Furthermore, the center of waveguide 20' may be offset relative to the center of cladding 10'. Under such characteristic dimensions, the output spot of the mode converter is typically an elliptical spot, making it difficult to obtain a circular spot. Since the optical fiber spot is circular, this leads to mode field mismatch. Additionally, because the electric field vibration directions of the TE and TM modes are different, even with the same structure, the mode spots of two different polarization states will exhibit different behaviors. For example, the mode field of an optical fiber is typically 9.6 mm in diameter. The perfect circle, while the terminal optical field of the mode converter is perpendicular to the TE mode along the vertical axis 9. Horizontal axis 7 The ellipse, with TM modulus as 6 on the vertical axis Horizontal axis 8 The waveguide pattern is elliptical. This indicates a difference in coupling performance, meaning there is polarization-dependent loss. Furthermore, in CMOS technology, the waveguide 20' pattern can only be designed in a planar dimension. The TE and TM modes also exhibit different losses during transmission, exacerbating polarization-dependent loss. Therefore, designing a mode-spot coupler that achieves high coupling efficiency in both the TE and TM modes while ensuring that the mode spots of both polarization states are similar in size and circular in shape is extremely difficult.

[0055] Example 1

[0056] like Figure 2 As shown, in one embodiment of the present invention, the optical transmission component includes a laser 11, a first optical chip 20 and a first optical fiber 12. The first optical chip 20 includes an optical multiplexer 21 and a first mode converter 22.

[0057] Among them, laser 11 is used to generate laser light, optical multiplexer 21 is used to multiplex laser light, and a second mode converter 13 is provided between the first optical chip 20 and the first optical fiber 12. The first mode converter 22 is used to amplify the mode of the light emitted from the optical multiplexer 21, and the second mode converter 13 is used to amplify the mode of the light emitted from the first mode converter 22.

[0058] Since the optical multiplexer 21 includes polarization multiplexing functionality, it may introduce multiple polarization states, leading to polarization-related loss problems. Figure 3 The diagram illustrates the amplification effect of the first mode converter 22 and the second mode converter 13 on the mode spot. It can be seen that the first mode converter 22 on the optical chip and the second mode converter 13 outside the optical chip amplify the mode spot of the output light of the optical multiplexer 21, respectively. This reduces the requirement for the mode spot amplification capability of the first mode converter 22, so that the first mode converter 22 only needs to have high conversion efficiency for different polarization states and can appropriately adjust the size of the mode spot. This can avoid polarization-related losses while meeting the overall coupling efficiency between the first optical chip 20 and the first optical fiber 12, and greatly reduce the design difficulty of the first mode converter 22.

[0059] In one embodiment, the second mode converter 13 includes a first lens having positive optical power.

[0060] The mode spot converted by the first mode spot converter 22 is often too small after it exits the optical chip, making it difficult to meet the requirement of direct coupling into the first optical fiber 12. By reasonably setting the focal length and position of the first lens, the size of the mode spot can be easily adjusted. When the mode spot is magnified twice by the first lens in free space, a mode field matching the first optical fiber 12 can be obtained.

[0061] Furthermore, the first lens can be a GRIN lens (gradient refractive index lens). This type of lens controls the light propagation path by continuously changing the refractive index inside the material (rather than relying on the surface curvature), and has the advantages of flexible structural design, small size, and high integration convenience.

[0062] like Figure 2 As shown, in one embodiment, the optical transmitting component further includes a third lens 14, and the first optical chip 20 further includes an edge coupler 24 and an optical modulator 23. The laser 11, the third lens 14, the edge coupler 24, the optical modulator 23, and the optical multiplexer 21 are coupled sequentially. The third lens 14 and the edge coupler 24 are used to couple the laser light generated by the laser 11 to the optical modulator 23, and the optical modulator 23 is used to modulate the laser light.

[0063] In one embodiment, the laser 11 is provided in plurality, and the optical modulator 23 and the edge coupler 24 can be provided in plurality corresponding to the laser 11. The optical multiplexer 21 multiplexes the laser light generated by the plurality of lasers 11.

[0064] In other embodiments, the laser 11, the edge coupler 24 and the optical modulator 23 can also be provided in one, and the first optical chip 20 can further include a beam splitter provided between the edge coupler 24 and the optical modulator 23, the beam splitter being used to split the laser light, and the optical modulator 23 can be provided in plurality corresponding to the split laser light. The optical multiplexer 21 multiplexes the split laser light.

[0065] Preferably, the difference between the conversion efficiencies of the TE mode and the TM mode of the first mode spot converter 22 for the outgoing light of the optical multiplexer 21 is less than or equal to 10%. By approximating the conversion efficiencies of different polarization states, polarization-dependent loss can be largely avoided. More preferably, the difference between the conversion efficiencies of the TE mode and the TM mode of the first mode spot converter 22 is less than or equal to 5%. It can be understood that for the outgoing light of the optical multiplexer 21, the best result is achieved when the conversion efficiencies of the TE mode and the TM mode of the first mode spot converter 22 are equal.

[0066] Preferably, the ellipticity of the TE mode spot and the ellipticity of the TM mode spot of the outgoing light of the first mode spot converter 22 are both less than or equal to 1.5. The ellipticity is the ratio of the maximum diameter to the minimum diameter of the spot. By ensuring that the spots of different polarization states can both approach a circle, the introduction of mode field mismatch in the process of inputting the spot into the first optical fiber 12 is avoided. More preferably, the ellipticity of the TE mode spot and the ellipticity of the TM mode spot are both less than or equal to 1.3. It can be understood that for the outgoing light of the first mode spot converter 22, the best result is achieved when the ellipticity of the TE mode spot and the ellipticity of the TM mode spot are both 1.

[0067] Preferably, the difference between the diameters of the TE mode spot and the TM mode spot of the outgoing light of the first mode spot converter 22 is less than or equal to 1.5 μm. By ensuring that the sizes of the spots of different polarization states are close to each other, a more close-to-optimal coupling efficiency can also be achieved. It should be noted that for an elliptical or other non-circular spot, the maximum diameter should be taken at the same time, or the minimum diameter should be taken at the same time, or the effective diameter should be calculated by backstepping the effective area. It can be understood that for the outgoing light of the first mode spot converter 22, the best result is achieved when the diameters of the TE mode spot and the TM mode spot are equal.

[0068] Figure 4The first mode spot converter 22 is shown in a front view, a side view and a top view (the front view is on the upper left of the drawing, the side view is on the right of the front view, and the top view is below the front view). Specifically, the first mode spot converter 22 includes a first cladding layer 221 and a first waveguide 222 disposed in the first cladding layer 221 and extending along a first direction, the width W2 of the first waveguide 222 gradually decreases along the first direction, and the height H2 is equal, and the end face of the first waveguide 222 close to the second mode spot converter 13 is a circle or an even-numbered regular polygon.

[0069] In this structure, the difference between the conversion efficiencies of the TE mode and the TM mode of the first mode spot converter 22 is small, and the ellipticity of the TE mode spot and the TM mode spot of the outgoing light is small, close to a circle, and the difference between the diameters of the TE mode spot and the TM mode spot is small, close to equal.

[0070] For example, the first direction is the direction in which the optical multiplexer 21 points to the second mode spot converter 13.

[0071] Preferably, the end face of the first waveguide 222 close to the first mode spot converter 22 is a square. In actual design, since the height of the first waveguide 222 is often determined by the SOI wafer or fab process and cannot be arbitrarily changed, the width W2 of the first waveguide 222 can be set to the height value H2.

[0072] Preferably, the width W1 of the first cladding layer 221 is equal to the height H1, which is beneficial to form a circular spot. In actual design, since the height H1 of the first cladding layer 221 is often determined by the SOI wafer process and cannot be arbitrarily changed, the width W1 of the first cladding layer 221 can be set to the height value H1.

[0073] Preferably, a gap is provided between the end of the first waveguide 222 close to the second mode spot converter 13 and the end of the first cladding layer 221 close to the second mode spot converter 13, which is beneficial to spot expansion.

[0074] The shape and size of the first waveguide 222 and the first cladding layer 221 close to the end of the optical multiplexer 21 are generally determined by the output waveguide of the optical multiplexer 21, and can be designed according to actual needs.

[0075] Figure 5 and Figure 6The first mode spot converter 22 is shown in a front view, a side view and a top view (the front view is on the upper left of the drawing, the side view is on the right of the front view, and the top view is below the front view) in other embodiments. Specifically, the first mode spot converter 22 can also include a first cladding layer 221 and a plurality of second waveguides arranged in the first cladding layer 221 and extending along the first direction. A single waveguide is limited by the material thickness and is usually large in size, while multiple waveguides can reduce the size of each waveguide to a smaller size, facilitate mode spot expansion, and increase the variable spacing between waveguides, which also introduces more variables in waveguide design and makes it easier to improve and balance the coupling efficiency of TE and TM modes.

[0076] For example, the first direction is the direction in which the optical multiplexer 21 points to the second mode spot converter 13.

[0077] In a specific embodiment as shown in FIG. 6, the second waveguide is provided with three second waveguides 223, 224 and 225. The second waveguide 223 is arranged at one end close to the optical multiplexer 21, and the second waveguides 224 and 225 are arranged on both sides of the second waveguide 223 along the width direction of the second waveguide 223, so that the light incident through the second waveguide 223 can be coupled to the second waveguides 224 and 225. Figure 5 Further, the second waveguide 223 can include a straight waveguide segment and an inverted taper segment connected along the first direction, the second waveguide 224 can include a positive taper segment and an inverted taper segment connected along the first direction, and the second waveguide 225 can include a positive taper segment and an inverted taper segment connected along the first direction. The positive taper segment of the second waveguide 224 and the positive taper segment of the second waveguide 225 are respectively located on both sides of the inverted taper segment of the second waveguide 223.

[0078] The second waveguides 223, 224 and 225 can have the same height H4, and their bottom surfaces are located on the same plane.

[0079] In another specific embodiment as shown in FIG. 7, the second waveguide is provided with three second waveguides 226, 227 and 228. The second waveguide 226 is arranged at one end close to the optical multiplexer 21, and the second waveguides 227 and 228 are arranged in sequence along the width direction of the second waveguide 226 and connected to the end of the second waveguide 226 close to the second mode spot converter 13, so that the light incident through the second waveguide 226 can be coupled to the second waveguides 227 and 228.

[0080] Figure 6

[0081] ​​Furthermore, the second waveguide 226 may include a straight waveguide segment and a positive conical segment connected along the first direction, and the second waveguide 227 and the second waveguide 228 each include an inverted conical segment.

[0082] For the aforementioned first mode converter 22 structure with multiple second waveguides, those skilled in the art can achieve any one or more of the following technical effects through reasonable structural parameter design: "For the output light of the optical multiplexer 21, the difference in conversion efficiency between the TE mode and the TM mode of the first mode converter 22 is less than or equal to 10%", "For the output light of the first mode converter 22, the ellipticity of both the TE mode and the TM mode is less than or equal to 1.5", and "For the output light of the first mode converter 22, the difference in diameter between the TE mode and the TM mode is less than or equal to 1.5 μm". For example, at the end near the second mode converter 13, the diameter of the TE mode and the TM mode can be adjusted by adjusting the spacing between the multiple second waveguides; increasing the width W4 of the second waveguides helps to reduce the ellipticity of the TE mode and the TM mode; adopting an axisymmetric or centrosymmetric design for the multiple second waveguides helps to reduce the difference in conversion efficiency between the TE mode and the TM mode, and so on.

[0083] Of course, the first mode converter 22 can also adopt other specific design structures.

[0084] like Figure 7 As shown, in one embodiment, the optical transmitting component may further include a first optical isolator 15, with the second mode converter 13 and the first optical isolator 15 sequentially disposed between the first optical chip 20 and the first optical fiber 12. The first optical isolator 15 can isolate reverse light.

[0085] like Figure 8 As shown, in another embodiment, the optical transmitting component may also include at least one first optical isolator 15, and a plurality of second mode converters 13 are provided between the first optical chip 20 and the first optical fiber 12, with the first optical isolator 15 disposed between adjacent second mode converters 13. By reasonably setting the position and parameters of the second mode converters 13, the two sides of the first optical isolator 15 can be made to be nearly parallel light, which is beneficial to the operation of the first optical isolator 15.

[0086] Example 2

[0087] like Figure 9 As shown, in one embodiment of the present invention, the optical receiving component includes a second optical chip 40 and a second optical fiber 31. The second optical chip 40 includes a photoelectric converter 41 and a third mode converter 42. A fourth mode converter 32 is provided between the second optical chip 40 and the second optical fiber 31.

[0088] The fourth mode field converter 32 is configured to reduce the mode field of the light emitted by the second optical fiber 31, and the third mode field converter 42 is configured to reduce the mode field of the light emitted by the fourth mode field converter 32. The photoelectric converter 41 is configured to perform photoelectric conversion on the light emitted by the third mode field converter 42.

[0089] The polarization state of the external optical signal is mixed after being transmitted through the second optical fiber 31, which causes polarization-dependent loss. Figure 10 The fourth mode field converter 32 and the third mode field converter 42 are configured to reduce the mode field. As shown in the schematic diagram, the fourth mode field converter 32 outside the optical chip and the third mode field converter 42 on the optical chip are configured to reduce the mode field of the light emitted by the second optical fiber 31, which reduces the requirement for the mode field reduction capability of the third mode field converter 42. The third mode field converter 42 only needs to have high conversion efficiency for different polarization states and can appropriately adjust the size of the mode field, thereby meeting the overall coupling efficiency between the second optical fiber 31 and the second optical chip 40 while avoiding polarization-dependent loss, and greatly reducing the design difficulty of the third mode field converter 42.

[0090] In an embodiment, the fourth mode field converter 32 includes a second lens having positive focal power.

[0091] The third mode field converter 42 cannot couple a large mode field into the photoelectric converter 41 with high efficiency in order to ensure that it has similar conversion efficiency for different polarization states. By reasonably setting the focal length and position of the second lens, the size of the mode field can be conveniently adjusted. After the mode field is preliminarily reduced by the second lens, the third mode field converter 42 can conveniently perform mode field conversion with high efficiency.

[0092] In an embodiment, the second lens can be a GRIN lens (gradient index lens). This type of lens controls the light propagation path by the continuous change of the refractive index inside the material (rather than relying on the surface curvature), which has the advantages of flexible structure design, small size, and high integration convenience.

[0093] Preferably, when the TE mode mode field and the TM mode mode field of the light emitted by the fourth mode field converter 32 are both circular, the difference between the conversion efficiency of the TE mode and the conversion efficiency of the TM mode of the third mode field converter 42 is less than or equal to 5%. More preferably, the difference between the conversion efficiency of the TE mode and the conversion efficiency of the TM mode of the third mode field converter 42 is less than or equal to 1%. It can be understood that when the TE mode mode field and the TM mode mode field of the light emitted by the fourth mode field converter 32 are both circular, the third mode field converter 42 has the best effect when the conversion efficiency of the TE mode is equal to the conversion efficiency of the TM mode.

[0094] Preferably, the third mode converter 42 has a conversion efficiency difference of less than or equal to 10% for TE and TM modes when the fourth mode converter 32 has a TE mode spot diameter and a TM mode spot diameter of the same size. More preferably, the third mode converter 42 has a conversion efficiency difference of less than or equal to 5% for TE and TM modes when the fourth mode converter 32 has a TE mode spot diameter and a TM mode spot diameter of the same size. It is understood that the third mode converter 42 has the best performance when it has a conversion efficiency difference of 0% for TE and TM modes when the fourth mode converter 32 has a TE mode spot diameter and a TM mode spot diameter of the same size.

[0095] Since the TE mode and the TM mode usually have the same size of circular mode spot in the optical fiber, the fourth mode converter 32 also has the same size of circular mode spot for TE and TM modes. In this case, the third mode converter 42 has the best performance when it has a conversion efficiency difference of 0% for TE and TM modes.

[0096] Figure 11 The front view, the side view and the top view of the third mode converter 42 are shown in a specific embodiment (the front view is on the top left of the drawing, the side view is on the right of the front view, and the top view is on the bottom of the front view). Specifically, the third mode converter 42 includes a second cladding 421 and a third waveguide 422 disposed in the second cladding 421 and extending along a second direction, the third waveguide 422 has a gradually decreasing width W6 along the second direction and an equal height H6, and the end face of the third waveguide 422 close to the fourth mode converter 32 is a circle or an even-numbered regular polygon.

[0097] For example, the second direction is the direction in which the photoelectric converter 41 points to the fourth mode converter 32.

[0098] It is understood that, due to the reversibility of the optical path, the conversion efficiency of the third mode converter 42 for TE and TM modes can be close to uniform when the light is incident forward or reversely, so that the third mode converter 42 can also avoid introducing polarization-dependent loss when it couples the light emitted by the fourth mode converter 32 to the photoelectric converter 41.

[0099] Preferably, the end face of the third waveguide 422 close to the fourth mode converter 32 is a square. In actual design, the height H6 of the third waveguide 422 is usually determined by the SOI wafer or the fab process and cannot be changed arbitrarily, so the width W6 of the third waveguide 422 can be set to the height value H6.

[0100] Preferably, the width W5 of the second cladding layer 421 is equal to the height H5, which is conducive to forming a circular spot. In actual design, the height H5 of the second cladding layer 421 is often determined by the process of the SOI wafer and cannot be changed at will, and the width W5 of the second cladding layer 421 can be set to the height value H5.

[0101] Preferably, a gap is provided between the third waveguide 422 close to one end of the fourth mode spot converter 32 and the second cladding layer 421 close to one end of the fourth mode spot converter 32, which is conducive to spot confinement.

[0102] The shape and size of the third waveguide 422 and the second cladding layer 421 close to one end of the photoelectric converter 41 are generally determined by the input waveguide of the photoelectric converter 41 and can be designed according to actual needs.

[0103] Figure 12 and Figure 13 The front view, side view and top view of the third mode spot converter 42 in other specific embodiments are shown (the front view is on the top left of the drawing, the side view is on the right of the front view, and the top view is below the front view). Specifically, the third mode spot converter 42 can also include a second cladding layer 421 and a plurality of fourth waveguides arranged in the second cladding layer 421 and extending along the second direction. A single waveguide is limited by the thickness of the material and is usually large in size, while multiple waveguides can reduce the size of each waveguide to a smaller size, which is conducive to spot expansion; at the same time, the variable of the spacing between the waveguides is increased, and more variables are introduced in the waveguide design, which is easier to obtain the improvement and balance of the TE mode and TM mode coupling efficiency.

[0104] For example, the second direction is the direction in which the photoelectric converter 41 points to the fourth mode spot converter 32.

[0105] In a specific embodiment as shown in Figure 12 The fourth waveguide is provided with three fourth waveguides 423, 424 and 425. The fourth waveguide 423 is arranged close to one end of the photoelectric converter 41, and the fourth waveguides 424 and 425 are arranged on both sides of the fourth waveguide 423 along the width direction of the fourth waveguide 423, so that the light incident through the fourth waveguides 424 and 425 can be coupled to the fourth waveguide 423.

[0106] Further, the fourth waveguide 423 can include a straight waveguide segment and an inverted taper segment connected along the second direction, the fourth waveguide 424 can include a positive taper segment and an inverted taper segment connected along the second direction, and the fourth waveguide 425 can include a positive taper segment and an inverted taper segment connected along the second direction. The positive taper segment of the fourth waveguide 424 and the positive taper segment of the fourth waveguide 425 are respectively located on both sides of the inverted taper segment of the fourth waveguide 423.

[0107] The fourth waveguide 423, the fourth waveguide 424 and the fourth waveguide 425 can have the same height and their bottom surfaces are all located on the same plane.

[0108] In such Figure 13 In another specific embodiment shown, three fourth waveguides are provided, namely fourth waveguide 426, fourth waveguide 427, and fourth waveguide 428. Fourth waveguide 426 is disposed near one end of photoelectric converter 41. Fourth waveguide 427 and fourth waveguide 428 are arranged sequentially along the width of fourth waveguide 426 and connected to the end of fourth waveguide 426 near the second mode converter 13, so that light incident through fourth waveguide 427 and fourth waveguide 428 can be coupled to fourth waveguide 426.

[0109] Furthermore, the fourth waveguide 426 may include a straight waveguide segment and a positive conical segment connected along the second direction, and the fourth waveguide 427 and the fourth waveguide 428 each include an inverted conical segment.

[0110] For the aforementioned third-mode converter 42 structure with multiple second waveguides, those skilled in the art can design reasonable structural parameters to achieve the same or similar conversion efficiency for TE and TM modes. Specific design principles can be found in the relevant description in Embodiment 1, and will not be elaborated upon here.

[0111] Of course, the third mode converter 42 can also adopt other specific design structures.

[0112] like Figure 14 As shown, in one embodiment, the optical transmitting component may further include a second optical isolator 33, with the fourth mode converter 32 and the second optical isolator 33 sequentially disposed between the second optical chip 40 and the second optical fiber 31. The second optical isolator 33 can isolate reflected light.

[0113] like Figure 15 As shown, in another embodiment, the optical transmitting component may also include at least one second optical isolator 33, and a plurality of fourth mode converters 32 are provided between the second optical chip 40 and the second optical fiber 31, with the second optical isolator 33 disposed between adjacent fourth mode converters 32. By reasonably setting the position and parameters of the fourth mode converters 32, the two sides of the second optical isolator 33 can be made to be nearly parallel, which is beneficial to the operation of the second optical isolator 33.

[0114] Example 3

[0115] This embodiment provides an optical module, including an optical transmitting component as described in Embodiment 1 and an optical receiving component as described in Embodiment 2, or including an optical transmitting component as described in Embodiment 1, or including an optical receiving component as described in Embodiment 2.

[0116] It will be apparent to those skilled in the art that the disclosure is not limited to the details of the above-exemplified embodiments and that the disclosure can be implemented in other particular forms without departing from the spirit or essential characteristics of the disclosure. The presently disclosed embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the disclosure being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No feature of the claims is to be construed as limiting the claims to the exact nature of the features described therein.

[0117] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. An optical transmitting component, the optical transmitting component comprising a laser, a first optical chip, and a first optical fiber, the first optical chip comprising an optical multiplexer, characterized in that, The laser is used to generate laser light, the optical multiplexer is used to multiplex the laser light, the first optical chip further includes a first mode converter, a second mode converter is provided between the first optical chip and the first optical fiber, the first mode converter is used to amplify the mode of the output light of the optical multiplexer, and the second mode converter is used to amplify the mode of the output light of the first mode converter.

2. The optical transmitting component according to claim 1, characterized in that, For the output light of the optical multiplexer, the difference in conversion efficiency between the TE mode and the TM mode by the first mode converter is less than or equal to 10%; and / or For the output light of the first mode converter, the ellipticity of its TE mode mode and the ellipticity of its TM mode mode are less than or equal to 1.5; and / or For the output light of the first mode converter, the difference in diameter between the TE mode pattern and the TM mode pattern is less than or equal to 1.

5. .

3. The optical transmission component according to claim 1 or 2, characterized in that, The first mode converter includes a first cladding and a first waveguide disposed within the first cladding and extending along a first direction. The width of the first waveguide gradually decreases along the first direction while the height remains constant. The end face of the first waveguide near the second mode converter is circular or a regular polygon with an even number of sides.

4. The optical transmitting component according to claim 3, characterized in that, The end face of the first waveguide near the first mode converter is square; and / or The width and height of the first cladding layer are equal.

5. The optical transmitting component according to claim 1 or 2, characterized in that, The first mode converter includes a first cladding and a plurality of second waveguides disposed within the first cladding and extending along a first direction.

6. The optical transmitting component according to claim 1, characterized in that, The second mode converter includes a first lens having positive optical power.

7. The optical transmitting component according to claim 1, characterized in that, The optical transmission component further includes a first optical isolator, and the second mode converter and the first optical isolator are sequentially disposed between the first optical chip and the first optical fiber; and / or The optical transmission component further includes at least one first optical isolator, and a plurality of second mode converters are provided between the first optical chip and the first optical fiber, with the first optical isolator disposed between adjacent second mode converters.

8. An optical receiving component, the optical receiving component comprising a second optical chip and a second optical fiber, the second optical chip comprising a photoelectric converter, characterized in that, The second optical chip also includes a third mode converter, and a fourth mode converter is provided between the second optical chip and the second optical fiber. The fourth mode converter is used to reduce the mode of the emitted light from the second optical fiber. The third mode converter is used to reduce the mode of the emitted light from the fourth mode converter. The photoelectric converter is used to perform photoelectric conversion on the emitted light from the third mode converter.

9. The optical receiving component according to claim 8, characterized in that, For the output light of the fourth mode converter, when both its TE mode and TM mode modes are circular, the difference in conversion efficiency between the TE mode and TM mode of the third mode converter is less than or equal to 5%; and / or For the output light of the fourth mode converter, when the diameter of the TE mode spot and the diameter of the TM mode spot are the same, the difference in conversion efficiency between the TE mode and the TM mode of the third mode converter is less than or equal to 10%.

10. The optical receiving component according to claim 8 or 9, characterized in that, The third mode converter includes a second cladding and a third waveguide disposed within the second cladding and extending along a second direction. The width of the third waveguide gradually decreases along the second direction while the height remains constant. The end face of the third waveguide near the fourth mode converter is circular or a regular polygon with an even number of sides.

11. The optical receiving component according to claim 10, characterized in that, The end face of the third waveguide near the fourth mode converter is square; and / or The width and height of the second cladding layer are equal.

12. The optical receiving component according to claim 8 or 9, characterized in that, The third mode converter includes a second cladding and a plurality of fourth waveguides disposed within the second cladding and extending along a second direction.

13. The optical receiving component according to claim 8, characterized in that, The fourth mode converter includes a second lens having positive optical power.

14. The optical receiving component according to claim 8, characterized in that, The optical receiving component further includes a second optical isolator, and the fourth mode converter and the second optical isolator are sequentially disposed between the second optical chip and the second optical fiber; and / or The optical receiving component further includes at least one second optical isolator, and a plurality of fourth mode converters are provided between the second optical chip and the second optical fiber, with the second optical isolator disposed between adjacent fourth mode converters.

15. An optical module, characterized in that, It includes the optical transmitting component as described in any one of claims 1 to 7 or the optical receiving component as described in any one of claims 8 to 14.

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