# US 2013/0156418 A1 · Chip on flex optical subassembly

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- Number: US 2013/0156418 A1
- Document ID: US20130156418A1
- Status: Published application
- Kind: A1
- Application number: 13/715,738
- Filed: 2012-12-14
- Published: 2013-06-20
- Earliest claimed: 2011-12-14
- Assignees: Finisar Corporation
- Inventors: Brent Stapleton; Rajeev Dwivedi; Harold Young Walker, JR.; Gary Landry
- Web page: https://patentgrep.com/patent/US20130156418A1

## CPC

- G02B 6/4246: {Bidirectionally operating package structures}
- G02B 6/4257: {having a supporting carrier or a mounting substrate or a mounting plate (G02B6/3648 takes precedence)}
- G02B 6/4263: {of the transisitor outline [TO] can type}
- G02B 6/4269: {with heat sinks or radiation fins}
- G02B 6/4281: {the printed circuit boards being flexible (in general H05K1/147)}
- G02B 6/4283: {with electrical insulation means}
- G02B 6/4286: {Optical modules with optical power monitoring}
- G02B 6/4292: {the light guide being disconnectable from the opto-electronic element, e.g. mutually self aligning arrangements}
- G02B 6/4295: {coupling with semiconductor devices activated by light through the light guide, e.g. thyristors, phototransistors}
- H04B 10/40: Transceivers
- H04B 10/503: {Laser transmitters}
- H05K 13/046: {Surface mounting (surface mounted components H05K3/341)}
- H10W 72/0198: {batch processes}
- G02B 6/43: Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
- H10W 72/536: {the connected ends being ball-shaped}
- H10W 72/5363: {the connected ends being wedge-shaped}
- H10W 72/5522: {comprising gold [Au]}
- H10W 72/5524: {comprising aluminium [Al]}
- H10W 72/5525: {comprising copper [Cu]}
- H10W 72/884: {Die-attach connectors and bond wires}
- H10W 90/732: {between stacked chips}
- Y10T 29/4913: Assembling to base an electrical component, e.g., capacitor, etc.
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H04B: TRANSMISSION
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

One example embodiment includes an optical subassembly (OSA). The OSA includes a flex circuit, an optical port, and an active optical component subassembly. The flex circuit is constructed of at least one electrically-conductive layer and at least one electrical insulator layer. The optical port defines a barrel cavity and is mechanically coupled to the flex circuit at a flex connection. The active optical component subassembly is positioned within the barrel cavity and electrically coupled to the flex circuit.

## Claims

### Claim 1

An optical subassembly comprising:
a flex circuit constructed of at least one electrically-conductive layer and at least one electrical insulator layer;
an optical port defining a barrel cavity, the optical port mechanically coupled to the flex circuit at a flex connection; and
an active optical component subassembly positioned within the barrel cavity and electrically coupled to the flex circuit.

### Claim 2 (depends on 1)

The optical subassembly of claim 1, wherein the active optical component subassembly comprises an optical transmitter.

### Claim 3 (depends on 2)

The optical subassembly of claim 2, wherein the optical transmitter comprises a vertical cavity surface emitting laser (VCSEL).

### Claim 4 (depends on 3)

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 flex circuit at a connection region and the monitor photodiode and the VCSEL being mounted to a spacer top surface of the spacer heat/dissipater.

### Claim 5 (depends on 4)

The optical subassembly of claim 4, further comprising a plate fixed to the optical port and positioned within the barrel cavity.

### Claim 6 (depends on 1)

The optical subassembly of claim 1, further comprising a heat sink stiffener affixed to the flex circuit and configured to stiffen at least some portion of the flex circuit and act as a thermal sink for heat generated during operation of the optical subassembly.

### Claim 7 (depends on 6)

The optical subassembly of claim 6, wherein the active optical component subassembly is mechanically mounted to a contact face of the heat sink stiffener.

### Claim 8 (depends on 1)

The optical subassembly of claim 1, wherein the flex circuit comprises:
an optical component subassembly connection region to which the active optical component subassembly is electrically coupled; and
a PCB flex connection configured to communicate electrical signals between a host system and the optical component subassembly connection region.

### Claim 9 (depends on 1)

The optical subassembly of claim 1, wherein the active optical component subassembly comprises a PIN photodiode or an avalanche photodiode (“APD”).

### Claim 10

An optical subassembly comprising:
an optical port that defines a barrel cavity having two barrel openings positioned on orthogonal sides of the optical port;
a flex circuit including a first portion that extends along a first of the two orthogonal sides to substantially cover a first of the two barrel openings and a second portion that extends along the second of the two orthogonal sides to substantially cover a second of the two barrel openings;
a first active optical component subassembly that is electrically coupled to the first portion of the flex circuit such that the first active optical component assembly is positioned within the barrel cavity; and
a second active optical component subassembly that is electrically coupled to the second portion of the flex circuit such that the second active optical component subassembly is positioned within the barrel cavity.

### Claim 11 (depends on 10)

The optical subassembly of claim 10, wherein the first active optical component subassembly is configured to emit outbound optical signals through the barrel cavity; and the second active optical component is configured to receive inbound optical signals through the barrel cavity.

### Claim 12 (depends on 10)

The optical subassembly of claim 10, further comprising a bidirectional filter positioned in the optical port to allow outbound optical signals emitted by the first active optical component subassembly to pass therethrough and to reflect inbound optical signals towards the second active optical component subassembly.

### Claim 13 (depends on 10)

The optical subassembly of claim 10, wherein the flex circuit is constructed of at least one electrically-conductive layer and at least one electrical insulator layer.

### Claim 14 (depends on 10)

A transceiver module comprising the optical subassembly of claim 10.

### Claim 15

A method of constructing an array of chip on flex optical subassemblies, the method comprising:
epoxying a top cover, a top metal, a core, a bottom metal, and a bottom cover to create an array of flex circuits;
attaching a different one of a plurality of heat sink stiffeners to each of the flex circuits in the array of flex circuits;
electrically coupling a different one of a plurality of active optical component subassemblies to each of the flex circuit in the array of flex circuits; and
mounting a different one of a plurality of optical ports to each of the flex circuits in the array of flex circuits such that each of the plurality of active optical component subassemblies is positioned within a barrel cavity defined by one of the plurality of optical ports.

### Claim 16 (depends on 15)

The method of claim 15, further comprising simultaneously conducting a burn-in procedure on the array of chip on flex optical subassemblies.

### Claim 17 (depends on 16)

The method of claim 16, further comprising epoxying a perimeter-mounting structure configured to support borders of the top cover, the top metal, the core, the bottom metal, and the bottom cover during construction of the array of chip on flex optical subassemblies.

### Claim 18 (depends on 15)

The method of claim 15, further comprising mechanically coupling a different one of a plurality of active optical component subassemblies to each of the flex circuits in the array of flex circuits.

### Claim 19 (depends on 15)

The method of claim 15, further comprising mechanically coupling a different one of a plurality of active optical component subassemblies to each of the plurality of heat sink stiffeners.

### Claim 20 (depends on 15)

The method of claim 15, further comprising cutting individual chip on flex optical subassemblies from the array of chip on flex optical subassemblies.