Injection locking increases InP disc-laser modulation rate

May 1, 2011
Although silicon-on-insulator (SOI) modulators have been demonstrated for future on-chip integrated-photonics interconnect architectures, they require an external laser source and suffer from unavoidable tradeoffs in operation bandwidth, footprint, drive voltage, extinction ratio, and/or insertion loss.

Although silicon-on-insulator (SOI) modulators have been demonstrated for future on-chip integrated-photonics interconnect architectures, they require an external laser source and suffer from unavoidable tradeoffs in operation bandwidth, footprint, drive voltage, extinction ratio, and/or insertion loss. To avoid these tradeoffs, researchers at Eindhoven University of Technology (Eindhoven, the Netherlands), Ghent University (Ghent, Belgium), and the Institut des Nanotechnologies de Lyon (Ecully, France), collaborating within the framework of the ICT-FP7 project HISTORIC, have demonstrated for the first time how the direct modulation bandwidth of an indium phosphide (InP) disc laser—fabricated using CMOS-compatible techniques—is dramatically enhanced to a 15 GHz, 3 dB modulation bandwidth while consuming only 1 mW of power.

Optical injection locking is achieved by using two lasers designated master and slave. When the master laser’s light matches the wavelength of the slave laser, it provides it with a “photon bias” so that turning it on and off produces fewer oscillations, significantly improving the direct-current modulation bandwidth. The 20 Gbit/s directly modulated disc laser consumes only 50 fJ/bit energy and has a low drive voltage (a few hundred millivolts) that is compatible with future CMOS logic-level voltages. Even though the slave laser is currently external to the chip, the results are a promising step toward a fully integrated high-speed optical interconnect transmitter that will eventually include these two (master and slave) disc lasers simultaneously integrated on CMOS.

Contact Oded Raz at [email protected].

About the Author

Gail Overton | Senior Editor (2004-2020)

Gail has more than 30 years of engineering, marketing, product management, and editorial experience in the photonics and optical communications industry. Before joining the staff at Laser Focus World in 2004, she held many product management and product marketing roles in the fiber-optics industry, most notably at Hughes (El Segundo, CA), GTE Labs (Waltham, MA), Corning (Corning, NY), Photon Kinetics (Beaverton, OR), and Newport Corporation (Irvine, CA). During her marketing career, Gail published articles in WDM Solutions and Sensors magazine and traveled internationally to conduct product and sales training. Gail received her BS degree in physics, with an emphasis in optics, from San Diego State University in San Diego, CA in May 1986.

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