Low-spatial-coherence high-radiance broadband fiber source for speckle free imaging

• Published in: Optics letters Vol. 40; no. 20; p. 4607
• Main Authors: Redding, Brandon, Ahmadi, Peyman, Mokan, Vadim, Seifert, Martin, Choma, Michael A, Cao, Hui
• Format: Journal Article
• Language: English
• Published: United States 15.10.2015
• Subjects: Optical Fibers; Optical Imaging - instrumentation
• ISSN: 1539-4794
• DOI: 10.1364/OL.40.004607

We design and demonstrate a fiber-based amplified spontaneous emission (ASE) source with low spatial coherence, low temporal coherence, and high power per mode. ASE is produced by optically pumping a large gain core multimode fiber while minimizing optical feedback to avoid lasing. The fiber ASE source provides 270 mW of continuous wave emission, centered at λ=1055  nm, with a full width at half-maximum bandwidth of 74 nm. The emission is distributed among as many as ∼70 spatial modes, enabling efficient speckle suppression when combined with spectral compounding. Finally, we demonstrate speckle-free full-field imaging using the fiber ASE source. The fiber ASE source provides a unique combination of high power per mode with both low spatial and low temporal coherence, making it an ideal source for full-field imaging and ranging applications.