Half-Wave-Coupled Ring-FP Laser With 50-Channel 100-GHz-Spaced Wavelength Tuning

We report our latest experimental results of the half-wave-coupled rectangular ring-FP laser. All the waveguides of the device are active, and the thermooptic effect is employed to extend the tuning range beyond the free-spectral-range limit. Singleelectrode tuning of 20 channels with 100-GHz spacing is obtained. By combining five single-electrode-controlled tuning curves with different bias currents on fixed electrodes and with the thermoelectric cooler fixed at 20 °C, wavelength tuning of 50 channels with 100-GHz spacing covering the L-band is achieved with a side-mode suppression ratio up to 41 dB. Direct modulation at 2.5 Gb/s is also demonstrated. The simple and compact ring-FP laser has great potential as a low-cost tunable laser for many applications.