Most vertical-cavity surface-emitting lasers (VCSELs) operate at 850 nm in Ethernet and other shorter-range fiber-optic applications. With their small size and low cost, they have captured a large share of the laser market. In fact, they have replaced many of the more expensive and complex distributed-feedback (DFB) and Fabry-Perot (F-P) lasers.
But they haven't succeeded in longer-wavelength, longer-haul fiber applications where 1310- and 1550-nm lasers rule—yet. Picolight's 1310-nm VCSEL may change that. According to the company, it's the first 1310-nm VCSEL that fits longer-range applications. Unlike other lasers, it doesn't need any special cooling apparatus. It also generates very low electromagnetic interference.
Developing VCSELs with longer wavelengths has been a real challenge for designers because of materials and processing. But Picolight has achieved success with an exotic mix of indium, gallium, arsenide, and nitride on a galliumarsenide substrate in a proprietary process. The laser is poised to dominate short-and medium-range fiber applications, and the growing use of 4-Gbit/s Fibre Channel in storage area networks seems like a good place to start.
Picolight makes the VCSEL and the transmit optical subassembly (TOSA), but the company doesn't sell these items separately. Instead, its key product using this new technology is a small-form-factor pluggable (SFP) transceiver module that fully complies with the SFP multisource agreement (see the figure). It will work well in 1G, 2G, and 4G/s Fibre Channel applications.
Also, the module is fully compatible with Ethernet 1000BaseLX for 5- and 10-km applications. Using multimode fiber, it ranges up to about 200 to 300 m. A range of 10 km is possible with single-mode fiber. The transceiver complies with the SFF-8472 digital diagnostic feature set, which permits real-time monitoring of transceiver performance and system stability, as well.
The Picolight 4-Gbit/s, 1310-nm VCSEL transceiver is sampling now. It will be generally available in volume later in the first quarter.