Browse Prior Art Database

Integrated TE cooler for laser diode & driver chip on a Si Optical Bench

IP.com Disclosure Number: IPCOM000016479D
Original Publication Date: 2003-Jun-24
Included in the Prior Art Database: 2003-Jun-24
Document File: 3 page(s) / 54K

Publishing Venue

IBM

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Integrated TE cooler for laser diode & driver chip on a Si Optical Bench

Integrated TE Cooler for Laser Diode and Driver Chip on a Silicon Optical Bench

Disclosed is a novel structure using micro thermoelectric (TE) cooling elements on a Si optical bench and solder bumps to connect the TE elements to the laser diode which contains matching metal links. An additional aspect of this structure is to route the electrical connections to the laser diode through TE elements to avoid the thermal short that a conventional wirebond or solder bump would form. Scaling down the TE elements in size and forming them by microelectronic processing techniques increases the heat 2density (W/cm) across which a given temperature differential can be maintained, see US Pat. 5,712,448 for example.

Laser diodes used in telecommunications applications typically require cooling since the efficiency and reliability of the laser diodes decreases with increasing temperature 0(beyond about 40C). It is also desirable to have the devices operate in a relatively hot 0ambient temperature (70-80C). Typically, the laser diode is mounted on a substrate which is attached to the cold side of a thermoelectric cooler (TEC), see US pat. 4,802,178 or US 5,264,392. US pat. 5,264,392 also describes a Si subassembly mounted on a TE cooler which contains cavities to receive and align a laser diode, ball lens, optical fiber etc... Such assemblies are now commonly known as a Si optical bench (SiOB). The driver chip which provides signals and power to the laser diode is typically packaged separately from the laser diode because the power dissipated by it would exceed what can easily be cooled by conventional TE coolers. This requires additional levels of expensive packaging and limits the further integration of laser diodes and driver chips. Also, conventional TE coolers cost about $20-25 each due to their fabrication by bulk metallurgy and precision assembly processes.

1

Page 2 of 3

micro TEC elementsLaser diode

Link metallurgy on Laser Solder for joining n or p-type TE elements Link metallurgy on SiOB

Driver chip

Optical fiber in Si V groove

3 mm thick

Si Optical Bench (SiOB) ~10x8 mm

Laser diode

SiOB

By building a mi...