Patent Application
20250076576
The present disclosure generally relates to an on-chip structure for fiber array alignment by assisting edge coupler index-matching epoxy/oil filling.
Aspects of the present disclosure relate to an on-chip structure for fiber array alignment by assisting edge coupler index-matching epoxy/oil filling. Various issues may exist with conventional solutions for on-chip structures for fiber array alignment by assisting edge coupler index-matching epoxy/oil filling. In this regard, conventional systems and methods for on-chip structures for fiber array alignment by assisting edge coupler index-matching epoxy/oil filling may be costly, cumbersome, and/or inefficient.
Limitations and disadvantages of conventional systems and methods will become apparent to one of skill in the art, through comparison of such approaches with some aspects of the present methods and systems set forth in the remainder of this disclosure with reference to the drawings.
Shown in and/or described in connection with at least one of the figures, and set forth more completely in the claims are on-chip structures for fiber array alignment by assisting edge coupler index-matching epoxy/oil filling.
The following discussion provides various examples of semiconductor devices and methods of manufacturing semiconductor devices. Such examples are non-limiting, and the scope of the appended claims should not be limited to the particular examples disclosed. In the following discussion, the terms “example” and “e.g.” are non-limiting.
The figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present disclosure. In addition, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of the examples discussed in the present disclosure. The same reference numerals in different figures denote the same elements.
The term “or” means any one or more of the items in the list joined by “or”. As an example, “x or y” means any element of the three-element set {(x), (y), (x, y)}. As another example, “x, y, or z” means any element of the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}.
The terms “comprises,” “comprising,” “includes,” and/or “including,” are “open ended” terms and specify the presence of stated features, but do not preclude the presence or addition of one or more other features.
The terms “first,” “second,” etc. may be used herein to describe various elements, and these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, for example, a first element discussed in this disclosure could be termed a second element without departing from the teachings of the present disclosure.
Unless specified otherwise, the term “coupled” may be used to describe two elements directly contacting each other or describe two elements indirectly connected by one or more other elements. For example, if element A is coupled to element B, then element A can be directly contacting element B or indirectly connected to element B by an intervening element C. Similarly, the terms “over” or “on” may be used to describe two elements directly contacting each other or describe two elements indirectly connected by one or more other elements.
The system 100 may be a photonics integrated circuit, for example. The edge couplers 110 may be operable to couple a waveguide 114 from the photonic integrated circuit (PIC)/wafer to an external device. The etching process on the wafer, for example in a silicon photonics process, may result in an undercut 112 under the waveguide 114. The waveguide 114 may be operable to carry optical signals, for example single mode, and may be structured as a single mode fiber. In some embodiments, the wafer may be a silicon photonics wafer.
Typically, the modal field diameter (MFD) of edge couplers 110 may be approximately 4 micrometers, which may lead to inefficient fiber coupling. To enlarge the MFD to approximately 9 micrometers for better fiber coupling efficiency and better alignment tolerance with the external device to be connected, one approach may be to fill the undercuts 112 of edge couplers 110 with index-matching epoxy or oil.
Correspondingly, the filling of the undercuts 112 with the index-matching liquid may increase a mode field diameter at the facet of the waveguides. A mode field diameter at the facet of the waveguide 114 may be approximately 4 micrometers without the index-matching liquid, for example. In some embodiments, a mode field diameter at the facet of the waveguide 114 may be approximately 9 micrometers with the index-matching liquid.
This process may comprise making undercuts 112 during wafer fabrication, and then filling the undercuts 112 with an epoxy/oil before alignment of PIC with an external device that may be coupled. The epoxy/oil filling process may be very delicate because the undercut 112 cavity may be very small, and may require high precision tooling and/or manual operation. Another problem may be to monitor the epoxy/oil filling process and quality. For example, it may be difficult to determine whether the amount of epoxy/oil present may be enough to encapsulate the edge coupler's 110 waveguide 114 region.
The duct 140 may be a cavity operable to fill the undercuts 112 of the edge couplers 110, by forming a communicating vessel with the undercuts 112, the main buckets 120, the monitor buckets 130, 130a, and the duct 140. By adding an index-matching liquid to the main buckets 120, the index-matching liquid may flow from the main bucket 120 through the duct 140 to fill the undercuts 112 of the edge couplers 110, the middle monitor buckets 130a and the monitor buckets 130. By adding index-matching liquid to the main bucket 120, the undercuts 112, middle monitor buckets 130a closer to the main bucket 120 will be filled first. The monitor buckets 130 separated the most distance from the main bucket 120 may be filled last in time.
The main bucket 120 may be a cavity operable to add index-matching liquid into the system 100. Specifically, the opening of the main bucket 120 may be chosen large enough to easily add index-matching liquid into the system 100. In some embodiments, the opening may be the shape of a square with a side length of 0.5 millimeters. In some embodiments, the opening may be the shape of a circle with a diameter of 0.5 millimeters. The opening of the main bucket 120 may be suitable for the filling with the index-matching liquid by an automatic aligner. In some embodiments, the index-matching liquid may be an oil or an epoxy.
The monitor buckets 130, 130a may be cavities with an opening to monitor the filling process. The opening of the monitor buckets 130 may be chosen so that the fill level of the system 100 may be verified. Because the undercuts 112 and the openings between ribs may be very small and because of the ribs 116 and the waveguide 114, it may be more difficult to verify the fill status of the system 100 directly by observing from the top openings of the undercuts 112 under edge couplers 110. Thus, it may be advantageous to use monitor buckets 130, 130a. A separation distance between at least one of the one or more monitor buckets 130 and at least one of the one or more main buckets 120 may be greater than the separation distance between any one of the undercuts 112 and any of the one or more main buckets 120. In other words, to ensure that the fill status of the monitor buckets 130 may be indicative of the fill status of the undercuts 112, the monitor buckets 120 may be separated a larger distance than the undercuts 112 from the main buckets 120 used for filling. In some embodiments, there may be middle monitor buckets 130a that may be used to monitor intermediate fill statuses, accordingly.
It may be advantageous for filling that the plurality of undercuts 112, the one or more main buckets 120, and the one or more monitor buckets 130, 130a, and the duct 140 may be formed on a same layer of the wafer and/or may be of the same depth.
As will be clear to the person skilled in the art, many different arrangements of the system 100 may be envisaged, some which may be illustrated in
The present disclosure includes reference to certain examples, however, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the disclosure. In addition, modifications may be made to the disclosed examples without departing from the scope of the present disclosure. Therefore, it is intended that the present disclosure not be limited to the examples disclosed, but that the disclosure will include all examples falling within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023111223430 | Aug 2023 | CN | national |
