Abstract
Exploiting III-V semiconductor technologies, vertical external-cavity surface-emitting laser (VECSEL) technology has been identified for years as a good candidate to develop lasers with high power, large coherence and broad tunability. Combined with fiber amplification technology, tunable single-frequency lasers can be flexibly boosted to a power level of several tens of watts. Here, we demonstrate a high power, single frequency and broadly tunable laser based on VECSEL technology. This device emits in the near-infrared around 1.06 µm and exhibits high output power (>100 mW) with a low-divergence diffraction-limited TEM00 beam. It also features a narrow free-running linewidth of < 400 kHz, with high spectral purity (SMSR >55 dB), and continuous broadband tunability greater than 250 GHz (< 15 V piezo voltage, 6 kHz cutoff frequency) with a total tunable range up to 3 THz. In addition, a compact design without any movable intracavity elements offers a robust single-frequency regime. Through fiber amplification, a tunable single-frequency laser is achieved at an output power of 50 W covering the wavelength range from 1057 nm to 1066 nm. Excess intensity noise brought on by the amplification stage is in good agreement with a theoretical model. A low relative intensity noise (RIN) value of-145 dBc/Hz is obtained at 1 MHz and we reach the shot-noise limit above 200 MHz.