Novel techniques for realizing SGDBR DWDM sources without coarse tuning

The multi-wavelength transmitters for DWDM systems can be built with either multiple discrete lasers (DLs) or monolithically integrated multi-wavelength laser arrays (MWLAs). The output wavelengths of these sources must match a specified wavelength grid, so the critical issues of fabricating DWDM sources are wavelength accuracy and stability. We have demonstrated a simple approach for fabricating MWLAs using SGDBR lasers of which the sampling period varies from laser to laser. Arrays of 32 wavelengths with good wavelength uniformity and controllability have been demonstrated. However, the multi-wavelength output was achieved by tuning one of the two SGDBR mirrors to align the reflection spectra at their first order peaks. To simplify the wavelength control for each laser, we demonstrate here the laser arrays that can generate multiwavelength output without any current tuning. This approach may be even more advantageous for fabricating DL-type DWDM sources such that multiple wavelengths can be obtained from the same wafer to save the manufacture cost. The previous approach for fabricating DL-type sources is to vary the wavelength in the wafer scale, i.e., one wavelength from one wafer.