Chip on leadframe optical subassembly
One example embodiment includes an optical subassembly (OSA). The OSA includes a leadframe circuit, an optical port, and an active optical component subassembly. The active optical component subassembly is mounted to the leadframe circuit. The optical port is mechanically coupled to the leadframe circuit.
1. An optical subassembly comprising:
a leadframe circuit including a substantially parallel plurality of leads with at least a portion of the plurality of leads arranged as ground-signal-signal-ground (GSSG) transmission lines, the substantially parallel plurality of leads having first ends forming a connection region and second ends forming a respective plurality of leadframe connectors, the substantially parallel plurality of leads configured as GSSG transmission lines from the connection region to the second ends and the substantially parallel plurality of leads further configured with at least one bend between the connection region and the second ends with the at least one bend causing at least a portion of the substantially parallel plurality of leads to be substantially orthogonal to the connection region, the plurality of leadframe connectors configured for directly coupling to a respective plurality of printed circuit board connectors;
an optical port defining a barrel cavity extending along an axis, the optical port mechanically coupled around the connection region of the leadframe circuit; and
an active optical component subassembly positioned within the barrel cavity and substantially coplanar with the connection region of the leadframe, the active optical subassembly mechanically and electrically coupled to the leadframe circuit in the connection region, and wherein the active optical component subassembly electrically couples through wirebonds to the optical component subassembly connection regions of the leadframe circuit, the connection region of the leadframe and the active optical component both configured substantially orthogonal to the axis of the barrel cavity, and the plurality of leadframe connectors extending from the connection region continuing to be substantially orthogonal to the axis of the barrel cavity for a portion of the length of the plurality of leadframe connectors.
2. The optical subassembly of claim 1 , wherein the active optical component subassembly comprises an optical transmitter.
3. The optical subassembly of claim 2 , wherein the optical transmitter comprises a vertical cavity surface emitting laser (VCSEL).
4. The optical subassembly of claim 3 , wherein the active optical component subassembly comprises a monitor photodiode and a spacer/heat dissipater, the spacer heat/dissipater being directly mounted to the leadframe circuit at a connection region and the monitor photodiode and the VCSEL being mounted to a spacer top surface of the spacer heat/dissipater.
5. The optical subassembly of claim 1 , wherein the leadframe circuit comprises a leadframe pad in the connection region of the leadframe circuit.
6. The optical subassembly of claim 5 , further comprising a first casing formed about the leadframe pad of the leadframe circuit opposite the active optical component subassembly.
7. The optical subassembly of claim 6 , further comprising a second casing formed about the plurality of leads of the leadframe circuit.
8. The optical subassembly of claim 1 , wherein the connection region of the leadframe circuit is configured to communicate electrical signals between a host system and the active optical component subassembly.
9. An optical subassembly comprising:
a leadframe circuit including a substantially parallel plurality of leads with at least a portion of the plurality of leads arranged as ground-signal-signal-ground (GSSG) transmission lines, the substantially parallel plurality of leads having first ends forming a connection region including a leadframe pad and second ends forming a respective plurality of leadframe connectors, the substantially parallel plurality of leads configured as GSSG transmission lines from the connection region to the second ends and the substantially parallel plurality of leads further configured with at least one bend between the connection region and the second ends with the at least one bend causing at least a portion of the substantially parallel plurality of leads to be substantially orthogonal to the connection region, the plurality of leadframe connectors configured for directly coupling to a respective plurality of printed circuit board connectors; and
an active optical component subassembly at least mechanically coupled around the connection region of the leadframe pad and substantially coplanar with the connection region of the leadframe, the active optical subassembly electrically coupled to at least a portion of the plurality of leads and arranged to transmit or receive with a fiber along an axis substantially orthogonal to the active optical subassembly, wherein the active optical component subassembly is electrically coupled through wirebonds to the at least a portion of the plurality of leads, the connection region of the leadframe and the active optical component both configured substantially orthogonal to the axis, and the plurality of leadframe connectors extending from the connection region continuing to be substantially orthogonal to the axis for a portion of the length of the plurality of leadframe connectors.
10. The optical subassembly of claim 9 , further comprising a first casing formed about the leadframe pad of the leadframe circuit opposite the active optical component subassembly.
11. The optical subassembly of claim 10 , further comprising a second casing formed about the leads of the leadframe circuit.
12. A method, comprising:
mechanically coupling an active optical component subassembly around a connection region of a leadframe circuit, the active optical component subassembly substantially coplanar with the connection region of the leadframe, the leadframe circuit including a substantially parallel plurality of leads with at least a portion of the plurality of leads arranged as ground-signal-signal-ground (GSSG) transmission lines, the substantially parallel plurality of leads having first ends forming the connection region and second ends forming a respective plurality of leadframe connectors, the substantially parallel plurality of leads configured as GSSG transmission lines from the connection region to the second ends and the substantially parallel plurality of leads further configured with at least one bend between the connection region and the second ends with the at least one bend causing at least a portion of the substantially parallel plurality of leads to be substantially orthogonal to the connection region, the plurality of leadframe connectors configured for directly coupling to a respective plurality of printed circuit board connectors; and
electrically coupling the active optical component subassembly to the leadframe circuit in the connection region and arranged to transmit or receive with a fiber along an axis substantially orthogonal to the active optical subassembly, wherein the electrically coupling comprises wirebonding the active optical component subassembly to at least a portion of a plurality of leads on the leadframe circuit, the connection region of the leadframe and the active optical component both configured substantially orthogonal to the axis, and the plurality of leadframe connectors extending from the connection region continuing to be substantially orthogonal to the axis for a portion of the length of the plurality of leadframe connectors.
13. The method of claim 12 , further comprising mounting an optical port over the active optical component subassembly and to the leadframe circuit.
14. The method of claim 12 , further comprising forming casing around at least a portion of the leadframe circuit.