Fiber optic transceiver with a heat dissipating structure

A fiber optic transceiver comprising a substrate, a heat dissipating structure, a receptacle and a light source is disclosed. The substrate may have a hole extending therethrough. The heat dissipating structure may be coupled to the substrate and may comprise a major surface, a plurality of fins, a projecting member, and a plurality of insulating protrusions. The plurality of fins may project from the major surface of the heat dissipating structure away from the substrate. The projecting member may extend partially or completely through the hole of the substrate. The plurality of insulating protrusions may extend substantially perpendicularly from the major surface of the heat dissipating structure and coupled to the substrate. The plurality of insulating protrusions may be configured to separate the major surface of the heat dissipating structure with the substrate so as to reduce heat transfer between the substrate and the heat dissipating structure.

BACKGROUND

The demand for high-speed communication is ever increasing. Video on demand, high definition television, and video conferencing are some of the examples of applications that drive the demand for high-speed communication systems.

Increasing adoption of cloud computing by businesses further intensifies the need for the communication system to expand its bandwidth capacity. This demand pushes for a greater adoption for optical fiber networks not only for longer distance applications, but also for other applications that are traditionally performed by copper-based communication networks.

In an optical fiber network, a semiconductor light source is utilized to deliver optical signals over an optical fiber. While using the semiconductor light source provides a clear cost and operational efficiency advantage as compared to other light sources, some challenges may remain—in particular in the thermal management of the semiconductor light source

DETAILED DESCRIPTION

FIG. 1illustrates a block diagram of a fiber optic transceiver100. The fiber optic transceiver100may comprise a substrate130, one or more heat dissipating structures150, a receptacle120, a light source110, and an optical element170.

The substrate130may be a printed circuit board, as an example. The substrate130may comprise a hole130cextending therethrough. It should be appreciated that the hole130cmay alternatively be referred to as a via or any other term used to describe a void of material extending through the substrate130. The substrate130may comprise a first surface130aand a second surface130b. The second surface130bmay be opposite the first surface130a. The hole130cmay extend completely through from the second surface130bto the first surface130a.

The heat dissipating structure150may be coupled to the substrate130. The heat dissipating structure(s)150may comprise a major surface152, a plurality of fins158, a projecting member154, and a plurality of insulating protrusions156. The heat dissipating structure(s)150may be made from copper or aluminum or any other material that is capable of dissipating or conducting heat effectively. The heat dissipating structure(s)150may be integrally formed.

The major surface152of the heat dissipating structure(s)150may be disposed adjacent to the second surface130bof the substrate130. In some embodiments, the heat dissipating structure(s)150may be in direct physical contact with the second surface130bvia the plurality of insulating protrusions156. The major surface152of the heat dissipating structure(s)150may be disposed parallel to the second surface130bof the substrate130. The plurality of fins158may be projecting from the major surface152away from the substrate130. The projecting member154of the heat dissipating structure(s)150may extend through the hole130cof the substrate130. The projecting member154may be extending partially or completely through the hole130cfrom the second surface130bof the substrate130to the first surface130aof the substrate130.

The fiber optic transceiver100may further comprise a first metal wall162. The first metal wall162may be disposed facing the second surface130bof the substrate130. The first metal wall162may comprise a plurality of ribs164. Each of the plurality of ribs164may be distanced apart from one another so as to create air vents166on the first metal wall162.

The light source110may be optically coupled with the receptacle120. The light source110may be disposed on the projecting member154of the heat dissipating structure150. The light source110may be disposed on the projecting member154adjacent to the first surface130aof the substrate130. In one embodiment, the light source110may be a distributed feedback laser (DFB laser). In another embodiment, the light source110may be a Vertical Cavity Surface Emitting Laser (VCSEL), an edge-emitting laser such as Fabry Perot (FP) laser, an LED or any other type of solid-state light source.

The heat dissipating structure150may be configured to dissipate heat generated by the light source110. The plurality of fins158of the heat dissipating structure150may be disposed approximating the plurality of ribs164so as to provide cooling through an airflow that goes through the air vents166.

The plurality of insulating protrusions156may be extending substantially perpendicularly from the major surface152of the heat dissipating structure150. The plurality of insulating protrusions156may be coupled to the substrate130. The plurality of insulating protrusions156may be configured to separate the major surface152of the heat dissipating structure150with the substrate130so as to reduce heat transfer between the substrate130and the heat dissipating structure150. The plurality of insulating protrusions156may be coupled to the substrate130with a thermally insulating attachment member.

The receptacle120may be disposed adjacent to the substrate130. The receptacle120may be configured to receiver a fiber optic connector199. The receptacle120may be configured to receive an LC type fiber optic connector or an SC type fiber optic connector or other type of fiber optic connectors. The receptacle120may be optically coupled with the optical element170and the light source110. The optical element170may be configured to direct light emitted from the light source110to the receptacle120. The optical element170may be a mirror or a lens or any other optical component that is capable of directing light emitted from the light source110to the receptacle120.

Referring toFIGS. 2A-2C, the fiber optic transceiver200that may comprise an optical end201and an electrical end202is depicted. The optical end201may comprise a receptacle220and the electrical end202may comprise a plurality of electrical traces204. The optical end201may be configured to receive a fiber optic connector (not shown). The electrical end202may be coupled to a host circuit board (not shown).

The fiber optic transceiver200may further comprise a heat dissipating structure250, an optical filter272, an optical element270, a substrate230, a light source210, a first metal wall262, and a wall268. All components of the fiber optic transceiver200that are in common with the fiber optic transceiver100may share similar characteristics or may be identical.

Referring toFIG. 2B-2C, the heat dissipating structure250may be disposed proximate to the optical end201. The light source210may be disposed proximate to the optical end201to reduce optical loss between the light source210and the receptacle220. The heat dissipating structure250may be utilized to dissipate heat from the light source210. Therefore, the heat dissipating structure250is placed near to the optical end201of the fiber optic transceiver200. The heat dissipating structure250may be interposed between a second surface230bof the substrate230and the first metal wall262. The heat dissipating structure250may comprise a major surface252, a projecting member254, and a plurality of fins258. The heat dissipating structure250may be integrally formed. The major surface252of the heat dissipating structure250may be extending parallel to the second surface230bof the substrate230.

The projecting member254may be extending through a hole230cof the substrate230from the second surface230bto a first surface230aof the substrate230. The plurality of fins258may be projecting from the major surface252of the heat dissipating structure250towards the first metal wall262. The first metal wall262may comprise a plurality of ribs264. The plurality of ribs264may be separated by air vents266.

The wall268may be projecting from the first metal wall262towards the substrate230. The wall268may comprise an opening268a. The receptacle220may be disposed on the opening268aof the wall268. At least one surface258aof the plurality of fins258that extends orthogonally from the major surface252may be disposed approximating the wall268. The at least one surface258aof the plurality of fins258may be substantially parallel to the wall268.

The light source210may be optically coupled with the receptacle220. The light source210may be disposed on the projecting member254adjacent to the first surface230aof the substrate230. The projecting member254may comprise a mounting surface254a. The mounting surface254aof the projecting member254may be substantially parallel to the first surface230aof the substrate230. The light source210may be placed on the mounting surface254a. The projecting member254may be physically separated from the substrate230so as to prevent heat transfer from the substrate230to the projecting member254and the light source210.

The optical filter272and the optical element270may be optically coupled with the receptacle220. The light source210may be disposed between the optical filter272and the projecting member254of the heat dissipating structure250. In one embodiment, the fiber optic transceiver200may be a bidirectional fiber optic transceiver200. In the bidirectional fiber optic transceiver, outgoing light transmitted from the light source210and incoming light detected by the photo detector216are travelling in a single optical fiber (not shown). The incoming light and outgoing light may have a different wavelength. The optical filter272may be a wavelength selective beam splitter. The wavelength selective beam splitter may be configured to separate the incoming and outgoing light based on the differences in wavelength.

Referring toFIGS. 3A-3E, a fiber optic transceiver300with a heat dissipating structure350is depicted. The fiber optic transceiver300may comprise a controller380, a substrate330, a first metal wall362, a second metal wall365, a wall368, a first photo detector314, a second photo detector316, a driver circuit312, and a detector circuit318. All the components of the fiber optic transceiver300that are in common with the fiber optic transceiver100,200may share similar characteristics or may be identical.

Referring toFIG. 3A, the heat dissipating structure350may comprise a plurality of fins358, a major surface352and a plurality of insulating protrusions356. The plurality of fins358may be separated by gaps359from a plurality of ribs364of the first metal wall362. The first metal wall362may be facing the second surface330bof the substrate330.

The first metal wall362may comprise a first surface362aand a second surface362badjacent to the first surface362a. The second surface362bof the first metal wall362may be disposed proximate to the second surface330bof the substrate330than the first surface362aof the first metal wall362.

The controller380may be disposed on the first surface330aof the substrate330. The second surface362bof the first metal wall362may be disposed approximating the controller380. The fiber optic transceiver300may further comprise a first thermal pad363. The first thermal pad363may be interposed between the second surface330bof the substrate330and the second surface362bof the first metal wall362. The first thermal pad363may be thermally conductive. The first thermal pad363may be configured to transfer heat from the controller380to the first metal wall362.

The first metal wall362may comprise a second metal wall365. The second metal wall365may be projecting from the first metal wall362to the second surface330bof the substrate330. The second metal wall365may be disposed between the plurality of fins358and the first thermal pad363. The fiber optic transceiver300may further comprise a second thermal pad367. The second thermal pad367may be disposed between the second metal wall365and the second surface330bof the substrate330. The second thermal pad367and the second metal wall365may be configured to reduce heat generated by the controller380travelling through the substrate330from reaching the light source310. The heat dissipating structure350may be surrounded by the second metal wall365, the wall368, the substrate330and the first metal wall362.

The fiber optic transceiver300may further comprise a third metal wall385and a heat dissipating block387. The third metal wall385may face the first surface330aof the substrate330. The third metal wall385may comprise an opening385a. The opening385aof the third metal wall385may be opposite to the controller380. The heat dissipating block387may be disposed on the opening385aof the third metal wall385. The heat dissipating block387may extend from the opening385atowards the controller380.

The heat dissipating block387may be made from different material from the third metal wall385. The third metal wall385may be made from zinc. The heat dissipating block387may be made from copper or aluminum or other materials with higher thermal conductivity than zinc, which is approximately 116 W/mK. The heat dissipating block387may be configured to dissipate heat from the controller380to the third metal wall385. The fiber optic transceiver300may further comprise a third thermal pad382. The third thermal pad382may be disposed between the controller380and the heat dissipating block387. The third thermal pad382may be configured to provide a direct thermal path between the controller380and the heat dissipating block387while reducing the pressure from the weight of the heat dissipating block387on the controller380.

Referring toFIG. 3B, the heat dissipating block387may be coupled to the opening385aof the third metal wall385by using an attachment member389. Referring toFIGS. 3A and 3C, the plurality of insulating protrusions356of the heat dissipating structure350may comprise a plurality of faces356asubstantially parallel to the major surface352of the heat dissipating structure350. The plurality of faces356aof the plurality of insulating protrusions356may be attached with an attachment member (not shown) to the substrate330.

The major surface352of the heat dissipating structure350may be approximately 20 to 45 times larger than one of the plurality of faces356aof the plurality of insulating protrusions356. When the size of the plurality of faces356ais smaller by more than 45 times from the major surface352of the heat dissipating structure350, the amount of thermal cross talk from the substrate330to the heat dissipating structure350may be minimal. However, the contact area between the heat dissipating structure350and the substrate330may also be minimal and may cause the heat dissipating structure350to be detached from the substrate330. By having one of the plurality of faces356aof the plurality of insulating protrusions35620 to 45 times smaller than the major surface352of the heat dissipating structure350, the heat dissipating structure350may be coupled to the substrate330with sufficient contact area while in the same time reducing the thermal cross talk between the substrate330and the heat dissipating structure350.

The projecting member354may comprise a mounting surface354a. The mounting surface354amay be parallel to the major surface352of the heat dissipating structure350. The light source310may be disposed on the mounting surface354aof the projecting member354.

Referring toFIG. 3D, the heat dissipating structure350may comprise an intersection354bbetween the projecting member354and the major surface352of the substrate330. The intersection354bmay be a curved surface. The curved surface of the intersection354bmay be advantageous to prevent heat concentration on the intersection between354band the major surface352so as to allow better heat dissipation from the projecting member354to the plurality of fins358.

FIG. 3Eillustrates a partial top view of an embodiment of the fiber optic transceiver300. The fiber optic transceiver300may be a bidirectional fiber optic transceiver. In this embodiment, the first and second photo detectors314,316, the driver circuit312and the detector circuit318may be disposed on the first surface330aof the substrate330. The mounting surface354aof the projecting member354may be surrounded by the first and second photo detectors314,316, the driver circuit312and the detector circuit318.

The first photo detector314may be a monitoring photo diode. The first photo detector314may be optically coupled with the light source310and may be electrically coupled with the driver circuit312. The first photo detector314may be configured to monitor output from the light source310and may be configured to communicate the information to the driver circuit312in order for the light source310to produce a stable output light.

The second photo detector316may be configured to detect light received from an optical fiber (not shown) for data communication purposes. The second photo detector316may be configured to generate electrical signal from the light detected. The detector circuit318may be configured to amplify the electrical signal generated by the second photo detector316.

The controller380shown inFIG. 3Amay be configured to control the driver circuit312. The controller380may control the driver circuit312to provide different current to the light source310when there is a change in the operating condition of the fiber optic transceiver300. For example, when temperature of the fiber optic transceiver300increases, the light source310may experience a decrease in light output. The controller380may be configured to receive information on the increase in the temperature and generate a control signal to the driver circuit312to increase the current provided to the light source310.

FIGS. 4A and 4Billustrate partial sectional views of a fiber optic transceiver400. The fiber optic transceiver400may comprise a substrate430, a heat dissipating structure450, a receptacle420, a first metal wall462, a wall468. All the components of the fiber optic transceiver400that are in common with the fiber optic transceiver100,200,300may share similar characteristics or may be identical.

The wall468may comprise an opening468aadjacent to a first surface430aof the substrate430. The receptacle420may be disposed in the opening468aof the wall468. The heat dissipating structure450may comprise a plurality of fins458. The plurality of fins458may comprise at least one surface458bof the plurality of fins458that extends parallel to the major surface452of the heat dissipating structure450. The at least one surface458bof the plurality of fins458may be separated by a first distance Y1from the second surface430bof the substrate430. The first metal wall462may comprise a second surface462b. The second surface462bof the first metal wall462may be disposed at a second distance Y2from the second surface430bof the substrate430. The first distance Y1may be larger than the second distance Y2.

Referring toFIG. 5, a fiber optic transceiver500having first and second heat dissipating structures550,551is depicted. The fiber optic transceiver500may comprise first and second receptacles520,521and a substrate530. All the components of the fiber optic transceiver500that are in common with the fiber optic transceiver100,200,300,400may share similar characteristics or may be identical.

The first and second heat dissipating structures550,551may be disposed on the same substrate530. In one embodiment, the first receptacle520may be configured to receive an optical signal from an optical fiber (not shown) and the second receptacle521may be configured to deliver an optical signal to another optical fiber (not shown).

Referring toFIGS. 6A-6D, an optical communication system698comprising a fiber optic transceiver600and a cage609is depicted. The fiber optic transceiver600may comprise a housing660, an optical port606, a substrate630, a heat dissipating surface652, a plurality of heat dissipating extensions658, a heat dissipating projection654, a heat dissipating block687, a controller680, and a light source610. All the components of the fiber optic transceiver600that are in common with the fiber optic transceiver100,200,300,400,500may share similar characteristics or may be identical.

Referring toFIG. 6A, the housing660may comprise a first region603and a second region605. The optical port606may be disposed at the first region603. The cage609may be configured to substantially enclose the second region605of the housing660. The cage609may comprise a plurality of cage pins694and a plurality of heat dissipating pins692. The plurality of cage pins694may be configured to secure the cage609to a host circuit board (not shown).

Referring toFIG. 6B, a plurality of electrical contacts604may be disposed on the substrate630at the second region605of the housing660. The heat dissipating block687and the controller680may be disposed at the second region605of the housing660. The heat dissipating block687and the controller680may be disposed proximate to the optical port606but distanced away from the plurality of electrical contacts604.

Referring toFIGS. 6B-6C, the substrate630may be disposed within the housing660. The substrate630may extend from the first region603to the second region605of the housing660. The substrate630may comprise an opening630c. The opening630cmay extend from the first surface630ato the second surface630bof the substrate630. The heat dissipating surface652may be disposed adjacent to the second surface630bof the substrate630at the first region603of the housing660. The plurality of heat dissipating extensions658may comprise a plurality of heat dissipating fins. The plurality of heat dissipating extensions658may project from the heat dissipating surface652away from the substrate630.

The heat dissipating projection654may extend perpendicularly from the heat dissipating surface652to the first surface630aof the substrate630through the opening630cof the substrate630. The light source610may be disposed on the heat dissipating projection654proximate to the first surface630aof the substrate630. The light source610may be optically coupled with the optical port606.

Referring toFIGS. 6B and 6D, the cage609may comprise a first metal surface691and a second metal surface693. The heat dissipating projection654may extend from the heat dissipating surface652in a first direction. The plurality of cage pins694may project from the first metal surface691in a direction opposite to the first direction. The plurality of heat dissipating extensions658may be projecting from the heat dissipating surface652in a second direction. The plurality of heat dissipating pins692may be projecting from the second metal surface693in a direction opposite to the second direction.

Different aspects, embodiments or implementations may, but need not, yield one or more of the advantages. For example, by having one of the plurality of faces of the plurality of insulating protrusions 20 to 45 times smaller than the major surface of the heat dissipating structure, the heat dissipating structure may be coupled to the substrate with sufficient contact area while in the same time reducing the thermal cross talk between the substrate and the heat dissipating structure.

Although specific embodiments of the invention have been described and illustrated herein above, the invention should not be limited to any specific forms or arrangements of parts so described and illustrated. For example, the fiber optic transceiver described above may be a single mode fiber optic transceiver, a multi mode fiber optic transceiver, a wavelength division multiplexing fiber optic transceiver or any other types of fiber optic transceiver. The scope of the invention is to be defined by the claims.