We report on the highly coherent modeless broadband continuous wave operation of a semiconductor vertical-external-cavity-surface-emitting laser. The laser design is based on a frequency-shifted-feedback scheme provided by an acoustooptic frequency shifter inserted in a linear or a ring traveling wave cavity. The gain mirror is a GaAs-based multiple quantum-well structure providing large gain at 1.07 mu m. This laser exhibits a coherent optical spectrum over 1.27 nm (330 GHz) bandwidth, with 70 mW output power and a high beam quality. The light polarization is linear (> 30 dB extinction ratio). The laser dynamics exhibits a low intensity noise close to class A regime, with a similar to 1.5 MHz cutoff frequency. The frequency noise spectral density shows a first-order low-pass like shape (130 kHz cutoff) leading to a Gaussian shape for homodyne interferometric signals. The measured beat width is similar or equal to 54 kHz and the coherence time of similar to 19 mu s. No nonlinear effects are observed, showing dynamics very close to theory. (C) 2015 Optical Society of America
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