Light emitting chip and optical module

Abstract

The invention discloses an optical emission chip and an optical module, the optical emission chip comprises an optical modulation unit and a first coupling unit which are connected with each other along an optical signal transmission direction, the optical modulation unit is used for modulating received light and then outputting the modulated light, and the first coupling unit is arranged at the output end of the optical emission chip. The coupling unit is used for receiving the signal light modulated and output by the light modulation unit, and coupling and outputting the modulated and output signal light; and the control unit is used for at least preventing the vertical polarized light from being transmitted to the light modulation unit when light is reversely transmitted to the light modulation unit from the first coupling unit. According to the invention, the problem of large light reflection of the output end of the light emitting chip caused by transmission of the vertical polarized light in the light emitting chip can be avoided.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor integration technology, and particularly to an optical emission chip and an optical module. Background Art

[0002] Generally, the working process of an optical emission chip can be briefly described as follows: a light source is coupled into the optical emission chip through an input end mode spot conversion structure, and then is sequentially transmitted through a waveguide to basic units or integrated devices on an optical chip such as a beam splitter and a modulator, and finally is output through an output end mode spot conversion structure.

[0003] The standard requirement for the optical reflection at the output end of the optical emission chip is less than -26 dB. That is to say, when light is reversely coupled into the optical emission chip from the output end of the optical emission chip, that is, when light is input from the output end of the optical emission chip to the input end of the optical emission chip, the wavelength of the light satisfies within the range of the central wavelength ± 6.5 nm and is in any polarization state, and the optical reflection at the output end of the optical emission chip is required to be less than -26 dB.

[0004] Since the light source coupled at the input end of the optical emission chip is generally horizontally polarized light and the integrated devices on the optical emission chip all work in the horizontally polarized state, for the light reversely input from the output end of the optical emission chip, if it is horizontally polarized light, the reflection is small; if it is vertically polarized light, there will be a large reflection in some basic units or integrated devices on the optical emission chip. Summary of the Invention

[0005] The purpose of the present invention is to provide an optical emission chip and an optical module to reduce the optical reflection at the output end of the optical emission chip.

[0006] To achieve one of the above-mentioned invention purposes, an embodiment of the present invention provides an optical emission chip, which is characterized in that the optical emission chip includes an optical modulation unit and a first coupling unit connected to each other along the optical signal transmission direction, the optical modulation unit is used for modulating the received light and then outputting it, the first coupling unit is arranged at the output end of the optical emission chip, and is used for receiving the signal light output after being modulated by the optical modulation unit and coupling and outputting the modulated signal light;

[0007] It further includes a control unit, which is used for when light is reversely transmitted from the first coupling unit to the optical modulation unit, the control unit at least blocks the transmission of vertically polarized light to the optical modulation unit.

[0008] As a further improvement of an embodiment of the present invention, the control unit is arranged between the optical modulation unit and the first coupling unit, and the control unit only allows horizontally polarized light to be transmitted to the optical modulation unit.

[0009] As a further improvement of an embodiment of the present invention, the control unit is a polarizer.

[0010] As a further improvement of an embodiment of the present invention, the control unit includes a polarization separation module and an absorption module. The polarization separation module is connected to the output end of the optical modulation unit and the input end of the first coupling unit, and the absorption module is connected to the reverse output end of the polarization separation module;

[0011] The polarization separation module outputs the horizontally polarized light transmitted in reverse from the first coupling unit to the optical modulation unit, and outputs the light with other polarization states transmitted in reverse from the first coupling unit to the absorption module, and the absorption module absorbs the received light.

[0012] As a further improvement of an embodiment of the present invention, the control unit includes a polarization separation module and a dissipation module. The polarization separation module is connected to the output end of the optical modulation unit and the input end of the first coupling unit, and the dissipation module is connected to the reverse output end of the polarization separation module;

[0013] The polarization separation module outputs the horizontally polarized light transmitted in reverse from the first coupling unit to the optical modulation unit, and outputs the light with other polarization states transmitted in reverse from the first coupling unit to the dissipation module, and the dissipation module dissipates the optical power of the received light to 0.

[0014] As a further improvement of an embodiment of the present invention, the polarization separation module is a polarization separation device or a polarization rotation separation device;

[0015] When the polarization separation module is a polarization separation device, the polarization separation module directly outputs the vertically polarized light transmitted in reverse from the first coupling unit;

[0016] When the polarization separation module is a polarization rotation separation device, the polarization separation module outputs the vertically polarized light transmitted in reverse from the first coupling unit after polarization rotation.

[0017] As a further improvement of an embodiment of the present invention, the absorption module is a germanium material absorption structure.

[0018] As a further improvement of an embodiment of the present invention, the dissipation module is a lossy waveguide or a PN junction absorption structure.

[0019] As a further improvement of an embodiment of the present invention, the optical emission chip further includes a second coupling unit, and the second coupling unit is connected to the optical modulation unit for coupling the externally input light and transmitting it to the optical modulation unit.

[0020] As a further improvement of an embodiment of the present invention, both the first coupling unit and the second coupling unit are edge couplers.

[0021] As a further improvement of an embodiment of the present invention, the optical modulation unit at least includes an optical modulator and an optical power monitoring unit. The optical modulator is connected to the second coupling unit and the control unit, and the optical power monitoring unit is connected to the output end of the optical modulator for monitoring the optical power at the output end of the optical modulator.

[0022] As a further improvement of an embodiment of the present invention, the optical emission chip further includes a beam splitting unit. The beam splitting unit is connected to the output end of the second coupling unit for splitting the coupled light with a reduced light spot into at least two paths for transmission, and each path is connected with an optical modulation unit, a control unit and a first coupling unit.

[0023] To achieve the above-mentioned invention purpose, the present invention provides an optical module, and the optical module includes the optical emission chip as described above.

[0024] The beneficial effect of the present invention is that a control unit is arranged between the input end and the output end of the optical emission chip. For light with any polarization state that is reversely input from the output end of the optical emission chip, after passing through this control unit, at least the vertical polarized light can be blocked from being transmitted to the optical modulation unit, avoiding large optical reflection at the output end of the optical emission chip caused by the transmission of the vertical polarized light within the optical emission chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of an optical emission chip in an embodiment of the present invention;

[0026] Figure 2 is a schematic structural diagram of a test optical path for optical reflection at the output end of an optical emission chip in an embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of the working process of a control unit in an embodiment of the present invention;

[0028] Figure 4 is a schematic structural diagram of an optical emission chip in another embodiment of the present invention;

[0029] Figure 5 is a schematic diagram of the working process of a control unit in another embodiment of the present invention (when the polarization separation module is a polarization separator);

[0030] Figure 6 is a schematic diagram of the working process of a control unit in another embodiment of the present invention (when the polarization separation module is a polarization rotation separator). DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0032] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0033] The present invention provides an optical emission chip. The optical emission chip includes an optically modulating unit and a first coupling unit connected to each other along the optical signal transmission direction. The optically modulating unit is used to modulate the received light and then output it. The first coupling unit is disposed at the output end of the optical emission chip and is used to receive the signal light output after being modulated by the optically modulating unit, and couple and output the modulated signal light; it further includes a control unit, which is used to at least block the transmission of vertically polarized light to the optically modulating unit when light is transmitted in the reverse direction from the first coupling unit to the optically modulating unit.

[0034] In the present invention, the optical emission chip can be a modulator chip integrated with a light source, or a modulator chip that receives externally input light, or an optical emission chip integrated with an optical receiving chip.

[0035] This embodiment will take the modulator chip that receives externally input light as an example for specific description. Then, the optical emission chip further includes a second coupling unit, which is connected to the optically modulating unit and is used to couple the externally input light and transmit it to the optically modulating unit.

[0036] As Figure 1 shown, an optical emission chip provided by this embodiment includes a second coupling unit 100, an optically modulating unit 200, and a first coupling unit 300 that are sequentially connected from the input end A to the output end B of the optical emission chip.

[0037] The second coupling unit 100 is disposed at the input end A of the optical emission chip and is used to couple the externally input light and transmit it to the optically modulating unit 200.

[0038] In an embodiment of the present invention, the second coupling unit 100 is an edge coupler, such as a mode spot converter. Specifically, when the second coupling unit 100 is a mode spot converter, when an external light source is disposed at the input end A of the optical emission chip and performs optical coupling with the second coupling unit 100, the second coupling unit 100 receives the input light of the external light source and reduces the light spot of the input light, so that the coupled light energy after the light spot is reduced can be transmitted between the silicon waveguide on the optical emission chip and other optical units or optical devices.

[0039] In other embodiments of the present invention, the second coupling unit 100 may also be a vertical coupler, such as a grating coupler or the like.

[0040] The present invention does not limit the specific type of the coupling device of the second coupling unit 100, and can be designed and adjusted according to actual requirements.

[0041] The input end of the optical modulation unit 200 is connected to the output end of the second coupling unit 100. The optical modulation unit 200 receives the coupled light with the reduced light spot, and modulates and outputs the coupled light with the reduced light spot.

[0042] Specifically, the optical modulation unit 200 at least includes an optical modulator 210 and an optical power monitoring unit 220. The optical modulator 210 is connected to the second coupling unit 100 and the first coupling unit 300. The optical power monitoring unit 220 is connected to the output end of the optical modulator 210 and is used to monitor the optical power at the output end of the optical modulator 210.

[0043] Of course, the optical modulation unit 200 may further include functional devices such as a wavelength division multiplexer connected to the optical modulator 210. The present invention does not limit the type, quantity, and installation position of this functional device, and can be designed and adjusted according to the actual design requirements and application scenarios of the optical emission chip.

[0044] The first coupling unit 300 is disposed at the output end of the optical emission chip and is connected to the output end of the optical modulation unit 200. It is used to receive the signal light output after being modulated by the optical modulation unit 200, and couple and output the modulated signal light.

[0045] Specifically, the first coupling unit 300 is an edge coupler, such as a mode spot converter. When the first coupling unit 300 is a mode spot converter, it is used to receive the signal light output after being modulated by the optical modulation unit 200, enlarge the light spot of the modulated signal light, and couple it with the optical fiber at the output end of the optical emission chip and then output.

[0046] Generally, the optical reflection standard requirement at the output end B of the optical emission chip is less than -26 dB. Since the light source coupled at the input end A of the optical emission chip is horizontally polarized light, and optical units such as the second coupling unit 100, the optical modulation unit 200, the first coupling unit 300, and the silicon waveguide for optical transmission are all designed to operate in the horizontal polarization state, when light with any polarization state is input from the output end B of the optical emission chip into the optical emission chip, optical units such as the second coupling unit 100, the optical modulation unit 200, the first coupling unit 300, and the silicon waveguide for optical transmission have a relatively large optical reflection for light with other polarization states (such as vertically polarized light).

[0047] Furthermore, the optical emission chip in this embodiment further includes a control unit 400, which is arranged between the optical modulation unit 200 and the first coupling unit 300. When there is light reversely transmitted from the first coupling unit 300 to the second coupling unit 100, the control unit 400 only allows horizontally polarized light to pass through or blocks vertically polarized light from passing through.

[0048] Combined with Figure 2 , when light with any polarization state is coupled with the first coupling unit 300 through the optical fiber 500 and the light with any polarization state is reversely transmitted from the first coupling unit 300 into the optical emission chip, after the light passes through the control unit 400, only horizontally polarized light is transmitted in the direction of the control unit 400 towards the optical modulation unit 200. The setting of the control unit 400 can avoid large optical reflection caused by the vertically polarized light reversely input from the output end of the optical emission chip during transmission in the optical emission chip, that is, when the optical wavelength input at the output end of the optical emission chip is within the range of the central wavelength ±6.5 nm and is light with any polarization state, the optical reflection at the output end of the optical emission chip can meet the requirement of being less than -26 dB.

[0049] In an embodiment of the present invention, the control unit 400 is a polarizer.

[0050] As Figure 3 shown, for the working process when the control unit 400 is a polarizer, the polarization state of the light output by the polarizer can be controlled by adjusting the waveguide structure design in the polarizer to be the horizontal polarization state.

[0051] In another embodiment of the present invention, as Figure 4 shown, the control unit 400 includes a polarization separation module 410 and an absorption module 420. The polarization separation module 410 is connected to the output end of the optical modulation unit 200 and the input end of the first coupling unit 300. The absorption module 420 is connected to the reverse output end of the polarization separation module 410.

[0052] The polarization separation module 410 outputs the horizontally polarized light that is reversely transmitted from the first coupling unit 300 to the optical modulation unit 200, and outputs the light with other polarization states that is reversely transmitted from the first coupling unit 300 to the absorption module 420, and the absorption module 420 absorbs the received light.

[0053] Specifically, the polarization separation module 410 is a polarization beam splitter (PBS) or a polarization rotation splitter (PSR).

[0054] When the polarization separation module 410 is a polarization beam splitter, the polarization separation module 410 directly outputs the vertically polarized light that is reversely transmitted from the first coupling unit 300; when the polarization separation module 410 is a polarization rotation splitter, the polarization separation module 410 outputs the vertically polarized light that is reversely transmitted from the first coupling unit 300 after polarization rotation.

[0055] Combined Figure 5 , when the polarization separation module 410 is a polarization beam splitter, when the light with any polarization state is coupled through the optical fiber 500 with the first coupling unit 300 and the light with any polarization state is reversely transmitted from the first coupling unit 300 to the optical emission chip, the polarization separation module 410 outputs the horizontally polarized light that is reversely transmitted from the first coupling unit 300 to the optical modulation unit 200, and directly outputs the vertically polarized light that is reversely transmitted from the first coupling unit 300 to the absorption module 420. The absorption module 420 absorbs the received vertically polarized light. Thereby, the vertical polarized light is prevented from being transmitted in the optical emission chip and causing a large optical reflection at the output end B of the optical emission chip.

[0056] Combined Figure 6 , when the polarization separation module 410 is a polarization rotation splitter, when the light with any polarization state is coupled through the optical fiber 500 with the first coupling unit 300 and the light with any polarization state is reversely transmitted from the first coupling unit 300 to the optical emission chip, the polarization separation module 410 outputs the horizontally polarized light that is reversely transmitted from the first coupling unit 300 to the optical modulation unit 200, performs polarization rotation on the vertically polarized light that is reversely transmitted from the first coupling unit 300, and outputs horizontally polarized light to the absorption module 420 after polarization rotation. The absorption module 420 absorbs the received horizontally polarized light. Thereby, the vertical polarized light is prevented from being transmitted in the optical emission chip and causing a large optical reflection at the output end B of the optical emission chip.

[0057] Specifically, the absorption module 420 is a germanium material absorption structure.

[0058] In another embodiment of the present invention, the control unit 400 includes a polarization separation module 410 and a dissipation module 420'. The polarization separation module 410 is connected to the output end of the optical modulation unit 200 and the input end of the first coupling unit 300. The dissipation module 420' is connected to the reverse output end of the polarization separation module 410.

[0059] The polarization separation module 410 outputs the horizontally polarized light transmitted in reverse from the first coupling unit 300 to the optical modulation unit 200, and outputs the light with other polarization states transmitted in reverse from the first coupling unit 300 to the dissipation module 420', and the dissipation module 420' dissipates the optical power of the received light to 0.

[0060] Specifically, the polarization separation module 410 is a polarization beam splitter (PBS) or a polarization rotation splitter (PSR).

[0061] When the polarization separation module 410 is a polarization beam splitter, the polarization separation module 410 directly outputs the vertically polarized light transmitted in reverse from the first coupling unit 300; when the polarization separation module 410 is a polarization rotation splitter, the polarization separation module 410 outputs the vertically polarized light transmitted in reverse from the first coupling unit 300 after polarization rotation.

[0062] Similarly, in combination with Figure 5 , when the polarization separation module 410 is a polarization beam splitter, when the light with any polarization state is coupled through the optical fiber 500 and the first coupling unit 300, and the light with any polarization state is transmitted in reverse from the first coupling unit 300 to the optical emission chip, the polarization separation module 410 outputs the horizontally polarized light transmitted in reverse from the first coupling unit 300 to the optical modulation unit 200, directly outputs the vertically polarized light transmitted in reverse from the first coupling unit 300 to the dissipation module 420', and the dissipation module 420' dissipates the optical power of the received vertically polarized light to 0, thereby avoiding the transmission of the vertically polarized light in the optical emission chip and causing a large optical reflection at the output end B of the optical emission chip.

[0063] In combination with Figure 6 , when the polarization separation module 410 is a polarization rotation splitter, when the light with any polarization state is coupled through the optical fiber 500 and the first coupling unit 300, and the light with any polarization state is transmitted in reverse from the first coupling unit 300 to the optical emission chip, the polarization separation module 410 outputs the horizontally polarized light transmitted in reverse from the first coupling unit 300 to the optical modulation unit 200, performs polarization rotation on the vertically polarized light transmitted in reverse from the first coupling unit 300, and outputs horizontally polarized light to the dissipation module 420' after polarization rotation, and the dissipation module 420' dissipates the optical power of the received horizontally polarized light to 0, thereby avoiding the transmission of the vertically polarized light in the optical emission chip and causing a large optical reflection at the output end B of the optical emission chip.

[0064] Specifically, the dissipation module 420' is a low-reflection loss waveguide or a PN junction absorption structure.

[0065] Furthermore, the optical emission chip in this embodiment further includes a beam splitting unit 600. The beam splitting unit 600 is connected to the output end of the second coupling unit 100 and is used to split the coupled light output by the second coupling unit 100 into at least two paths for transmission. Each path is connected with an optical modulation unit 200, a control unit 400, and a first coupling unit 300.

[0066] Specifically, the beam splitting unit 600 is a 3dB coupler that evenly splits the coupled light output by the second coupling unit 100 into two paths for transmission. Each transmission path is connected with an optical modulation unit 200, a control unit 400, and a first coupling unit 300.

[0067] Of course, the beam splitting unit 600 can also be designed as a multi-path beam splitter structure, as long as the optical power of each path of transmission meets the transmission requirements of subsequent silicon-based optical devices.

[0068] Furthermore, another optical power monitoring unit is provided on each transmission path after the output of the beam splitting unit 600. The other optical power monitoring unit is connected to the output end of the beam splitting unit 600 and is used to monitor the output optical power of each transmission path of the beam splitting unit 600.

[0069] The present invention also provides an optical module, and the optical module includes the optical emission chip described in any one of the above embodiments.

[0070] In summary, the present invention provides a control unit before the mode field conversion unit at the output end of the optical emission chip. For light with any polarization state reversely input from the output end of the optical emission chip, after passing through this control unit, at least the vertically polarized light can be blocked from transmitting to the optical modulation unit, avoiding large optical reflection at the output end of the optical emission chip caused by the transmission of vertically polarized light in the optical emission chip. That is, when the optical wavelength input at the output end of the optical emission chip is within the range of the central wavelength ±6.5nm and is any polarized light, the optical reflection at the output end of the optical emission chip can meet the requirement of being less than -26dB.

[0071] It should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0072] The series of detailed descriptions listed above are only specific descriptions of the feasible implementation manners of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent implementation manners or modifications made without departing from the technical spirit of the present invention should be included within the protection scope of the present invention.

Claims

1. A light-emitting chip, characterized in that, along the optical signal transmission direction, the light-emitting chip includes an optically modulating unit and a first coupling unit connected to each other. The optically modulating unit is configured to modulate the received light and then output it. The first coupling unit is disposed at the output end of the light-emitting chip and is configured to receive the signal light output after being modulated by the optically modulating unit, and couple and output the signal light output after being modulated; It further includes a control unit, which is configured to at least block the transmission of vertically polarized light to the optically modulating unit when light is transmitted in the reverse direction from the first coupling unit to the optically modulating unit.

2. The light-emitting chip according to claim 1, characterized in that, the control unit is disposed between the optically modulating unit and the first coupling unit, and the control unit allows horizontally polarized light to be transmitted to the optically modulating unit.

3. The light-emitting chip according to claim 2, characterized in that, the control unit is a polarizer.

4. The light-emitting chip according to claim 2, characterized in that, the control unit includes a polarization separation module and an absorption module. The polarization separation module is connected to the output end of the optically modulating unit and the input end of the first coupling unit, and the absorption module is connected to the reverse output end of the polarization separation module; the polarization separation module outputs the horizontally polarized light transmitted in the reverse direction from the first coupling unit to the optically modulating unit, outputs the light with other polarization states transmitted in the reverse direction from the first coupling unit to the absorption module, and the absorption module absorbs the received light.

5. The light-emitting chip according to claim 2, characterized in that, the control unit includes a polarization separation module and a dissipation module. The polarization separation module is connected to the output end of the optically modulating unit and the input end of the first coupling unit, and the dissipation module is connected to the reverse output end of the polarization separation module; the polarization separation module outputs the horizontally polarized light transmitted in the reverse direction from the first coupling unit to the optically modulating unit, outputs the light with other polarization states transmitted in the reverse direction from the first coupling unit to the dissipation module, and the dissipation module dissipates the optical power of the received light to 0.

6. The light-emitting chip according to claim 4 or 5, characterized in that, the polarization separation module is a polarization separation device or a polarization rotation separation device; when the polarization separation module is a polarization separation device, the polarization separation module directly outputs the vertically polarized light transmitted in the reverse direction from the first coupling unit; when the polarization separation module is a polarization rotation separation device, the polarization separation module outputs the vertically polarized light transmitted in the reverse direction from the first coupling unit after polarization rotation.

7. The light-emitting chip according to claim 4, characterized in that, the absorption module is a germanium material absorption structure.

8. The light-emitting chip according to claim 5, characterized in that, the dissipation module is a loss waveguide or a PN junction absorption structure.

9. The light-emitting chip according to claim 1, characterized in that, The optical emission chip further includes a second coupling unit, which is connected to the optical modulation unit and is used to couple the externally input light and transmit it to the optical modulation unit.

10. The optical emission chip according to claim 9, wherein, both the first coupling unit and the second coupling unit are edge couplers.

11. The optical emission chip according to claim 9, wherein, the optical modulation unit at least includes an optical modulator and an optical power monitoring unit. The optical modulator is connected to the second coupling unit and the control unit, and the optical power monitoring unit is connected to the output end of the optical modulator and is used to monitor the optical power at the output end of the optical modulator.

12. The optical emission chip according to claim 9, wherein, the optical emission chip further includes a beam splitting unit, which is connected to the output end of the second coupling unit and is used to divide the coupled light with a reduced spot size into at least two paths for transmission. Each path is connected with an optical modulation unit, a control unit and a first coupling unit.

13. An optical module, wherein, the optical module includes the optical emission chip according to any one of claims 1-12.

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