A fiber array structure coupled with a silicon photonic integrated chip

Abstract

The present invention discloses an optical fiber array structure coupled with a silicon photonic integrated chip, comprising: a waveguide passive chip and a light-conducting structure, wherein a V-shaped groove for fixing the light-conducting structure is etched on the waveguide passive chip, and the light-conducting structure is an optical fiber or an optical fiber ribbon; the optical mode field size of one end of the waveguide passive chip coupled with the light-conducting structure matches the optical mode field of a single-mode optical fiber, and the optical mode field size of one end coupled with the silicon photonic integrated chip matches the optical mode field of a mode spot converter in the silicon photonic integrated chip. The waveguide passive chip realizes the mode spot conversion function, and the mode field size of the light coupling structure in the silicon photonic integrated chip only needs to match that of the waveguide passive chip, and is not affected by the mode field of the single-mode optical fiber, which can reduce the difficulty of designing and manufacturing the light coupling structure in the silicon photonic integrated chip and improve the light coupling efficiency.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to an optical fiber array structure coupled with a silicon photonic integrated chip. Background Art

[0002] Silicon-based optoelectronic integrated chips based on silicon photonics technology can integrate multi-channel high-speed modulators, high-speed detectors, beam splitters / combiners, and wavelength division multiplexing / demultiplexing devices, which can meet large-capacity communications and are one of the ideal solutions for high-bandwidth, low-power, low-cost and high-speed optical interconnection.

[0003] In many usage scenarios, silicon photonic integrated chips need to be optically coupled with optical fiber arrays to realize the import and export of optical signals. The optical coupling effect between the two has a significant impact on the optical communication system. The size of the optical waveguide in the silicon photonic integrated chip is often in the order of hundreds of nanometers in width and height, while the mode field size of the single-mode optical fiber is in the order of 8-10um. This size mismatch will lead to large optical coupling losses. Although the optical mode field can be expanded by designing an optical mode spot converter structure on the silicon photonic integrated chip to improve the coupling efficiency, it is still difficult to expand it to the order of 8-10um, and it is often necessary to use a cantilever beam structure to etch away the substrate silicon near the mode spot conversion structure. The process is complicated and not conducive to the back-end process development of silicon photonic integrated chips. Summary of the invention

[0004] To solve the above technical problems, the present invention provides a fiber array structure coupled to a silicon photonic integrated chip. In order to have a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. This summary is not a general review, nor is it intended to identify key / important components or describe the scope of protection of these embodiments. Its only purpose is to present some concepts in a simple form as a preface to the detailed description that follows.

[0005] The present invention adopts the following technical solution:

[0006] Provided is an optical fiber array structure coupled with a silicon photonic integrated chip, comprising: a waveguide passive chip and a light-conducting structure, wherein a V-shaped groove for fixing the light-conducting structure is etched on the waveguide passive chip;

[0007] The optical mode field size of one end of the waveguide passive chip coupled to the optical conduction structure matches the optical mode field of the single-mode optical fiber, and the optical mode field size of one end coupled to the silicon photonic integrated chip matches the optical mode field of the mode spot converter in the silicon photonic integrated chip;

[0008] The light-conducting structure is an optical fiber or an optical fiber ribbon.

[0009] Furthermore, the waveguide passive chip is provided with one or more of a beam combiner, a beam splitter, a wavelength division multiplexer, and a wavelength demultiplexer.

[0010] Furthermore, the waveguide passive chip is a passive chip based on silicon nitride waveguide / silicon oxynitride waveguide / silicon dioxide waveguide / thick silicon waveguide.

[0011] Furthermore, the number of the V-grooves is the same as the number of optical fibers in the light transmission structure.

[0012] Furthermore, the optical fiber array structure coupled with the silicon photonic integrated chip also includes: a cover plate; the coupling end of the optical fiber in the optical transmission structure is arranged above the V-groove, and the cover plate presses the front bare fiber position of the optical fiber and is cured and bonded with glue.

[0013] Furthermore, the waveguide passive chip is also provided with a second coupling structure, an optical waveguide and a third coupling structure; the second coupling structure is used to perform optical coupling with the first coupling structure on the silicon photonic integrated chip, the third coupling structure is used to perform optical coupling with the optical conduction structure, and the optical waveguide connects the second coupling structure and the third coupling structure.

[0014] The beneficial effects brought by the present invention are:

[0015] 1. The waveguide passive chip realizes the mode spot conversion function. The mode field size of the optical coupling structure in the silicon photonic integrated chip only needs to match that of the waveguide passive chip, and is not affected by the mode field of the single-mode optical fiber. This can reduce the design and production difficulty of the optical coupling structure in the silicon photonic integrated chip and improve the optical coupling efficiency.

[0016] 2. The optical beam splitting structure can be made in the waveguide passive chip, so there is no need to worry about the optical power tolerance of the silicon optical waveguide when using a high-power external laser. It only needs to split the beam through the optical beam splitting structure and then guide the multi-path light into the silicon optical integrated chip;

[0017] 3. In scenarios where a wavelength division multiplexer / demultiplexer is required, the wavelength division multiplexing / demultiplexing function is integrated into the waveguide passive chip without the need to be made into the silicon photonic integrated chip. This can prevent the performance of the silicon-based optical waveguide wavelength division multiplexing / demultiplexing device from being affected by temperature, resulting in the situation where it cannot work normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 Taking DR8PIC as an example, a schematic diagram of the structure of coupling the silicon photonic integrated chip with the optical fiber array structure of the present invention is shown;

[0020] Figure 2 Taking 2XFR4PIC as an example, the schematic diagram of the structure of coupling the silicon photonic integrated chip with the optical fiber array structure of the present invention is shown. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be clear that the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] like Figure 1-2 As shown, in some illustrative embodiments, the present invention provides an optical fiber array structure coupled to a silicon photonic integrated chip, comprising: a waveguide passive chip 1 , a cover plate 2 , and a light conducting structure 3 .

[0023] The waveguide passive chip 1 is used as a substrate of the light-conducting structure 3, on which a V-shaped groove 101 is etched for fixing the light-conducting structure 3, wherein the light-conducting structure 3 is an optical fiber or an optical fiber ribbon, which is a thin flat ribbon formed by 4 to 24 optical fibers arranged in parallel and cured by UV.

[0024] The waveguide passive chip 1 of this embodiment can also play the role of a mode spot converter. Specifically, the optical mode field size of the end of the waveguide passive chip 1 coupled to the optical conduction structure 3 matches the optical mode field of the single-mode optical fiber, and the optical mode field size of the end coupled to the silicon photonic integrated chip 4 matches the optical mode field of the mode spot converter in the silicon photonic integrated chip 4.

[0025] The number of V-grooves 101 is the same as the number of optical fibers in the light-conducting structure 3. The size of the V-grooves 101 should be designed to ensure that the mode field center of the coupled optical waveguide in the waveguide passive chip 1 substantially coincides with the mode field center of the optical fiber after the optical fiber is placed therein.

[0026] The coupling end of the optical fiber in the light transmission structure 3 is arranged above the V-shaped groove 101, and the cover plate 2 presses the front bare fiber position of the optical fiber and is cured and bonded with glue to ensure the stability of the structure.

[0027] The waveguide passive chip 1 realizes the function of mode spot conversion, so that the mode field size of the optical coupling structure in the silicon photonic integrated chip 4 only needs to match the waveguide passive chip 1, and is not affected by the single-mode optical fiber mode field. This can reduce the design and production difficulty of the optical coupling structure in the silicon photonic integrated chip 4 and improve the optical coupling efficiency.

[0028] In some illustrative embodiments, the waveguide passive chip 1 may be a passive chip based on silicon nitride waveguide / silicon oxynitride waveguide / silicon dioxide waveguide / thick silicon waveguide. Thick silicon waveguide refers to a silicon waveguide with a thickness of at least 3 um.

[0029] In some illustrative embodiments, a second coupling structure 102, an optical waveguide 103 and a third coupling structure 104 are also provided on the waveguide passive chip 1. The second coupling structure 102 is used to perform optical coupling with the first coupling structure 401 on the silicon photonic integrated chip. The third coupling structure 104 is used to perform optical coupling with the optical conductive structure 3. The optical waveguide 103 connects the second coupling structure 102 and the third coupling structure 104.

[0030] Because silicon materials are affected by two-photon absorption and free-carrier absorption effects, silicon photonic integrated chips are difficult to withstand large optical powers. Therefore, it is impossible to use high-power external lasers to introduce light into silicon photonic integrated chips through optical fibers. Instead, more low-power lasers and more-channel optical fiber arrays can be used, which increases both material costs and the size of the optical engine / module. At the same time, due to the large thermal-optical coefficient of silicon materials, the performance of some silicon-based passive waveguide devices (such as silicon-based wavelength division multiplexing / demultiplexing, etc.) is easily affected by temperature, resulting in limited use scenarios of silicon photonic integrated chips. Although adding thermal control structures to some passive waveguide devices in silicon photonic integrated chips can solve this problem to a certain extent, it increases the complexity of chip use and increases power consumption.

[0031] In order to solve the above technical problems, in this embodiment, one or more of a beam combiner, a beam splitter, a wavelength division multiplexer, and a wavelength demultiplexer are arranged on the waveguide passive chip 1.

[0032] The optical beam splitting structure in the waveguide passive chip 1 can realize beam splitting by using a high-power external laser through an optical fiber array structure, and then multiple light paths are introduced into the silicon optical integrated chip 4, without worrying about the optical power bearing problem of the silicon optical waveguide. At the same time, the wavelength division multiplexing / demultiplexing function is integrated into the waveguide passive chip 1, which can prevent the performance of the silicon-based optical waveguide type wavelength division multiplexing / demultiplexing device from being affected by temperature and failing to work properly.

[0033] The core spacing in the optical fiber array is generally 250um or 127um. The existence of the optical fiber array spacing makes the chip further restricted by the diameter of the optical fiber itself, that is, the size of the multi-channel high-integration silicon photonic integrated chip is restricted by the core spacing of the optical fiber array. The waveguide passive chip of this embodiment has the fan-out function of the optical interface, so that the distance between each optical port in the multi-channel high-integration silicon photonic integrated chip is no longer restricted by the core spacing of the optical fiber array.

[0034] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An optical fiber array structure, characterized in that: Used to couple with silicon photonic integrated chips, Including: waveguide passive chip and light conduction structure; The waveguide passive chip serves as a substrate for the optical transmission structure. A V-groove is etched on the waveguide passive chip for fixing the optical transmission structure. The optical transmission structure is a thin flat strip formed by 4 to 24 optical fibers arranged in parallel and cured by UV. The number of V-grooves is the same as the number of optical fibers in the optical transmission structure. The size of the V-groove is designed to ensure that the mode field center of the coupled optical waveguide in the waveguide passive chip coincides with the mode field center of the optical fiber after the optical fiber is placed. The second function of the waveguide passive chip is to act as a mode spot converter: the optical mode field size of one end of the waveguide passive chip coupled to the optical conduction structure matches the optical mode field of the single-mode optical fiber, and the optical mode field size of one end coupled to the silicon photonic integrated chip matches the optical mode field of the mode spot converter in the silicon photonic integrated chip; The waveguide passive chip is also provided with a second coupling structure, an optical waveguide and a third coupling structure; the second coupling structure is used to perform optical coupling with the first coupling structure on the silicon photonic integrated chip, the third coupling structure is used to perform optical coupling with the optical transmission structure, and the optical waveguide connects the second coupling structure and the third coupling structure; The waveguide passive chip is provided with one or more of a beam combiner, a beam splitter, a wavelength division multiplexer, and a wavelength demultiplexer; the wavelength division multiplexing / demultiplexing function is integrated in the waveguide passive chip, and does not need to be manufactured in a silicon photonic integrated chip.

2. The optical fiber array structure according to claim 1, characterized in that: The waveguide passive chip is a passive chip based on silicon nitride waveguide / silicon oxynitride waveguide / silicon dioxide waveguide / thick silicon waveguide.

3. The optical fiber array structure according to claim 2, characterized in that: The number of the V-grooves is the same as the number of optical fibers in the light-conducting structure.

4. The optical fiber array structure according to claim 3, characterized in that: Also includes: Cover plate; the coupling end of the optical fiber in the light transmission structure is arranged above the V-shaped groove, and the cover plate presses the front bare fiber position of the optical fiber and is cured and bonded with glue.

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