Widely Tunable Laser Using Reflecting Fabry–Perot Filters With Lossy Half-Wave Trenches

We report the design and experimental results of a widely tunable three-section laser by using reflecting Fabry-Perot filters with deeply etched lossy half-wave coupling trenches. Good performance in side-mode suppression ratio and wavelength tuning range has been demonstrated experimentally. By introducing moderate coupling loss in the half-wave coupling trenches, high-mode selectivity can be achieved. The single-mode selectivity can be further improved by introducing slight gain in the Fabry-Perot filters. Electrical tuning of 12 channels covering as large as 84-nm wavelength range with side-mode suppression ratio up to 48 dB has been demonstrated. The large wavelength tuning range is a result of large temperature induced gain spectrum shift, which is verified by amplified spontaneous emission measurements.