Constant output power and low linewidth in a simple wide-tuning DFB laser with multiwavelength grating

Step-tuning to widely spaced predefined wavelengths using a single current is demonstrated. A compound distributed-feedback-distributed-Bragg-reflector (DFB-DBR) GaInAsP laser structure including multiwavelength gratings (MWGs) on both sections is proposed. MWGs are fabricated by holographic lithography. Each MWG acts as a spectral comb filter. Using vernier effect between passive and active MWGs, DFB modes are successively selected. As wavelength selectivity is performed on the active medium without help of facet reflectivity, output power remains the same on all wavelengths. Four 4-nm-spaced DFB modes are accessed with constant optical output power. Advantages of such a configuration for integrated components are discussed.