Panasonic develops VCSEL with 12.5-Gbit/s data-transmission rate

May 31, 2005, Osaka, Japan--Panasonic has developed an 850-nm vertical-cavity surface-emitting laser (VCSEL) capable of high-speed 12.5-Gbit/s modulation at a low operating current of 8 mA. This laser will be used for low-cost optical communications approaches such as plastic fiber communication and spatial light transmission. The laser is based on an aluminum gallium arsenide/gallium arsenide structure.

For high-speed operation, it is essential to reduce the parasitic capacitance in the laser. The developed VCSEL has a planarized structure using benzocyclobutene resin, which has a low dielectric constant, formed around the light-emitting post structure. This structure reduces the parasitic capacitance to less than one-third of the conventional value, or from 0.7 to 0.2 pF. The change doubles the modulation bandwidth previously limited by the parasitic capacitance, realizing a data-transmission rate of 12.5 Gbit/s with a 12-GHz relaxation-oscillation frequency.

The optimization of the device structure, which uses current confinement by selective oxidation has pushed the threshold current down to 1 mA and the slope efficiency up to 1.1 W/A (close to three times higher than the conventional value). This has resulted in a low operating current of 8 mA for 12.5-Gbit/s modulation.

Panasonic wants to begin shipping two types of VCSELs (2.5 and 12.5 Gbit/s) in early 2006. Applications for 40 domestic and nine international patents have been filed. The company's research and development results were presented at the Conference on Lasers and Electro-Optics (CLEO) 2005, held in Baltimore, Maryland from May 22 to 27, 2005.

Panasonic is the leading brand by which Matsushita Electric Industrial Co. is generally known.