Optical systems using WDM are of increasing interest for telecommunications transmission, switching, wavelength routing, and broadcast networks, where often an array of sources at different wavelengths is needed. Conventionally this is achieved with separately packaged sources and WDM multiplexers. However, a considerable reduction in system complexity, along with potential cost reductions, can be achieved by reducing the number of separately packaged components. In this paper we describe a high performance multiple wavelength laser transmitter that operates at four wavelengths spaced by 4 nm around 1550 nm, in the erbium fiber amplifier window. The transmitter package includes an array of four DFB lasers along with a miniature diffraction grating and hybrid micro-optics for efficient coupling into a single mode output fiber. An array of micro-lenses bonded directly to the front facet of the laser array reduces alignment tolerances and minimizes optical losses. The compact package (5 X 3.5 X 1.5 cm) also includes novel ECL-level compatible laser drive circuitry that allows each laser in the array to be controlled and modulated independently at bit rates up to 2.5 Gbit/s. A thermoelectric cooler and thermistor provide temperature stabilization of the laser array. Prototype components have demonstrated mean launched powers of greater than -4 dBm per channel and laser wavelengths within +/- 0.3 nm of target for all channels simultaneously. Wavelength crosstalk between lasers caused by thermal effects was measured at less than 0.1 nm.