What is a Hybrid Silicon Laser?

A hybrid silicon laser is a new type of laser, developed in 2006 by Intel and the University of California Santa Barbara (UCSB). This laser is made from group III-V semiconductor materials (e.g. Gallium(III) arsenide, Indium(III) phosphide) of the same type used in mass-produced computer chips, as well as silicon. A hybrid silicon laser is distinct from the laser diodes we currently use in our computers and CD players, based on Indium Phosphide, which must be individually assembled and aligned for each unit, and cannot be mass-produced in the same way as computer chips.

Separate III-V semiconductor wafers must be used to fabricate current laser diodes. Hybrid silicon lasers are primarily made of silicon, and are fabricated on a silicon wafter, which we have extensive experience at mass-manufacturing thanks to photolithography and the computing revolution. Hybrid silicon lasers will greatly drop the cost of building a laser.

Although hybrid silicon lasers will also use indium phosphide to generate light, it does not use the chemical to route, detect, modulate, and amplify light, as in normal laser diodes, but instead uses silicon. Hybrid silicon lasers are a huge step towards the integration of optical systems with conventional computer chips, which could allow processing speeds and data transfer rates hundreds of times faster than the best we have today. These transfer rates would be on the terabit level rather than the gigabit or megabit level we see today.

Hybrid silicon lasers are part of a research programme called photonic computing, which wants to see computer chips use light in tangent with electrical impulses to process data. Light requires less energy per unit of data. Hybrid silicon lasers can be mass-produced on an industrial scale, with hundreds or more to a die. Numerous on-chip lasers would be required to make a computer primarily based on photonics. Another necessary step to true photonics would be the technology to literally stop light in a crystal, analogous to electron storage in current computer logic. Preliminary research has shown promising results in this direction.