M. Tawfieq, H. Wenzel, P. Della Casa, O. Brox, A. Ginolas, P. Ressel, D. Feise, A. Knigge, M. Weyers, B. Sumpf, and G. Tränkle

Published in:

Appl. Opt., vol. 57, no. 29, pp. 8680-8685 (2018).

Abstract:

Tunable high-power diode lasers are key components in various established and emerging applications. In this work, we present a compact hybrid master oscillator power amplifier (MOPA) laser system. The system utilizes a tunable GaAs-based sampled-grating (SG) distributed Bragg reflector (DBR) laser as the master oscillator (MO), which emits around a wavelength of 970 nm in a single longitudinal mode with a spectral width below 20 pm. The SG-DBR laser consists of two SGs, each of which can be thermally tuned with microheaters. By tuning one of the two SGs, a discrete wavelength tuning of 21.1 nm can be obtained with a Vernier mode spacing of about 2.3 nm. By tuning both SGs, 23.5 nm of quasi-continuous tuning is obtained, with a mode spacing of about 115 pm. The coupling of the beam emitted by the MO into a tapered power amplifier provides an amplified output power in the watt range having a nearly diffraction-limited beam with a propagation factor of M²_1/e² = 1.6. The combination of high power and wide wavelength tuning in a compact system makes this light source ideal for, among other things, nonlinear frequency conversion.

OCIS codes:

(140.3490) Lasers, distributed-feedback; (140.3600) Lasers, tunable; (250.5980) Semiconductor optical amplifiers; (130.3990) Micro-optical devices; (140.3613) Lasers, upconversion.

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