Transmitter optical subassembly (TOSA) lasers for digital and coarse wave division multiplexing applications are offered by Applied Optoelectronics Inc. The hermetically sealed devices feature high output power and 5.6-mm TO-style packaging, available in SC and LC styles. Low-noise light sources, the lasers are uncooled up to 4 Gb/s and have an optional extended temperature range from –40 to 85 °C. Fabry-Perot or distributed feedback lasers are available. The modules meet the environmental requirements of the European Restriction on Hazardous Substances regulations.