Selectable wavelength laser arrays for WDM applications

In the present talk will review some of the ongoing work considering DFB laser arrays for wavelength selectable lasers (WSL) and simultaneously modulated multichannel source (SMS) applications. To ensure output power levels and chirp performance similar to current DFB lasers with integrated electroabsorption (EA) modulators, a semiconductor optical amplifier (SOA) and an EA modulator are sometimes integrated with these arrays. We review the available data on uniformity, chirp and wavelength precision of these arrays, as well as the packaging requirements. An approach that separates a tunable wavelength source and the amplifier-modulator part into two different packages have also been suggested. For an SMS source, simultaneously modulated channels create significant cross talk penalties when propagating through a common SOA. However, without an SOA, a laser array with six directly modulated DFB lasers combined into a single output fiber, has been demonstrated.