The challenge of making a monolithic electrically tunable laser source for wavelength division multiplexing applications covering at least the 30 nm Erbium doped fiber amplifier optical window led to different approaches to extend the limited tuning range (< 15 nm) of common DBR lasers. In the following, we will comment on three types: the vertical coupler filter laser, the sampled-DBR laser or its improved version the super structure grating DBR (SSG- DBR) laser and the grating assisted coupler with sample rear reflector (GCSR) laser. These lasers use carrier induced index change geared up to achieve the wide electrical tuning. Their performance has been continually improved in term of tuning range, wavelength coverage, output power and side mode suppression. Wavelength coverage of 67 nm in a GCSR laser and of 62 nm in SSG-DBR lasers has been demonstrated requiring a three-tuning-current control. Their tuning mechanism and tuning characteristics are discussed as well as linewidth, power and wavelength switching speed. Various switching experiments have been performed that demonstrate switching times between 4 and 20 ns. The latency incurred when switching between wavelengths is due to the spontaneous carrier lifetime.