Techniques for reducing ingress of foreign matter into an optical subassembly
Techniques are disclosed for filling gaps formed between a press-fit component and an optical subassembly housing to introduce a seal or barrier that can prevent or otherwise mitigate the ingress of contaminants. In an embodiment, a layer of sealant material is applied to one or more surfaces of an optical component prior to press-fitting the component into an optical subassembly housing. Alternatively, or in addition to applying sealant to one or more surfaces of an optical component, a layer of sealant material may be disposed on an interface formed between an outer surface of the optical subassembly housing and the optical component press-fit into the same. Techniques disclosed herein are particularly well suited for small form-factor optical subassemblies that include one or more optical components press-fit into openings of a subassembly housing during manufacturing.
1. An optical subassembly comprising:
a housing having a plurality of sidewalls that provide a cavity there between;
an opening defined by at least one surface of the plurality of sidewalls that extends from an outer surface of the housing to the cavity;
an optical component assembly at least partially disposed within the opening, the optical component assembly being held in the opening at least in part based on an interference fit formed between the optical component assembly and the at least one surface of the plurality of sidewalls that define the opening;
a sealant layer disposed along an interface formed between a surface of the optical component assembly and the at least one surface defining the opening in order to reduce ingress of contaminants into the cavity; and
an external layer of sealant material disposed on an interface between an outer surface of a sidewall of the plurality of sidewalls and an outer surface of the optical component assembly.
2. The optical subassembly of claim 1 , wherein the sealant layer is formed from an epoxy.
3. The optical subassembly of claim 2 , wherein the epoxy is a thermally-conductive epoxy.
4. The optical subassembly of claim 1 , wherein the at least one surface defining the opening comprises a first surface and a second surface, the second surface extending substantially perpendicular to the first surface.
5. The optical subassembly of claim 4 , wherein at least a portion of the first and second surfaces include the sealant layer disposed thereon.
6. The optical subassembly of claim 1 , wherein the sealant layer is disposed in a non-continuous fashion along the interface formed between a surface of the optical component assembly and the at least one surface.
7. The optical subassembly of claim 1 , wherein the sealant layer is disposed in a continuous fashion such that the sealant layer surrounds the optical component assembly.
8. The optical subassembly of claim 1 , wherein the cavity provides a light path extending longitudinally from a first end of the housing to a second end.
9. The optical subassembly of claim 8 , wherein the optical component assembly comprises a filter arrangement, and wherein a filter element of the filter arrangement is optically coupled with the light path in response to the optical component assembly being disposed within the opening.
10. The optical subassembly of claim 9 , wherein the sealant layer is not in contact with the filter element.
11. The optical subassembly of claim 1 , wherein the sealant layer is a composite layer.
12. The optical subassembly of claim 1 , wherein the sealant layer provides structural support and provides at least some friction to hold the optical component assembly in the opening via the interference fit.
13. The optical subassembly of claim 1 , wherein the optical subassembly comprises a transmitter optical subassembly (TOSA) or a receiver optical subassembly (ROSA).
14. An optical transceiver comprising:
a transceiver housing; and
a first optical subassembly comprising a receiver optical subassembly (ROSA) or a transmitter optical subassembly (TOSA), the first optical subassembly comprising:
a housing having a plurality of sidewalls that provide a cavity there between;
an opening defined by at least one surface of the plurality of sidewalls that extends from an outer surface of the housing to the cavity;
an optical component assembly at least partially disposed within the opening, the optical component assembly being held in the opening at least in part based on an interference fit formed between the optical component assembly and the at least one surface of the plurality of sidewalls that define the opening; and
a first sealant layer disposed along an interface formed between a surface of the optical component assembly and the at least one surface defining the opening in order to reduce ingress of contaminants into the cavity;
a second optical subassembly comprising the other of the ROSA or the TOSA, the second optical subassembly comprising:
a housing having a plurality of sidewalls that provide a cavity there between;
an opening defined by at least one surface of the plurality of sidewalls that extends from an outer surface of the housing to the cavity;
an optical component assembly at least partially disposed within the opening, the optical component assembly being held in the opening at least in part based on an interference fit formed between the optical component assembly and the at least one surface of the plurality of sidewalls that define the opening; and
a second sealant layer disposed along an interface formed between a surface of the optical component assembly and the at least one surface defining the opening in order to reduce ingress of contaminants into the cavity.
15. The optical subassembly of claim 14 , wherein the first sealant layer is formed from an epoxy.
16. A method for forming an optical subassembly, the method comprising:
receiving an optical subassembly housing;
applying a first layer of sealant material to one or more press-fit optical component assemblies;
inserting the one or more press-fit optical component assemblies into corresponding openings of the optical subassembly housing; and
applying a second layer of sealant material on an interface formed between an external surface of the optical subassembly housing and an external surface of the one or more press-fit optical component assemblies.
17. The method of claim 16 , wherein the sealant material comprises an epoxy.