Talbot external cavity coherently combines ten laser diodes

Feb. 1, 2009
A method of phase-locking an array of ten index-guided tapered laser diodes has been devised by researchers at CNRS and the Alcatel-Tales III-V Lab (both in Palaiseau, France) and the University of Nottingham (Nottingham, England).

A method of phase-locking an array of ten index-guided tapered laser diodes has been devised by researchers at CNRS and the Alcatel-Tales III-V Lab (both in Palaiseau, France) and the University of Nottingham (Nottingham, England). The Talbot effect (a near-field diffraction effect in which a grating is repeatedly imaged at regular distances from the grating) is exploited by using a slightly tipped volume Bragg grating (VBG) as the output mirror; the tip selects an in-phase self-image and places it back on the diode array, sending light back into the diodes for phase-locking.

Click here to enlarge image

An acylindrical lens collimates the array’s fast-axis output. The VBG is designed to reflect 40% at the laser wavelength of 976 nm and has a spectral bandwidth of 0.3 nm, resulting in a laser bandwidth of 0.1 nm. The phase-locked laser array’s threshold current is 0.9 A; at a current of 3.9 A, the array reaches an output power of 1.7 W in its in-phase single main lobe mode. The far-field profile contains interference peaks, which at an output power of 1.2 W, are 1.2 mrad full-width at half-maximum (FWHM), close to the diffraction-limited width of 1 mrad. At higher power, the peaks broaden to 2.5 mrad FWHM. Contact David Paboeuf at david.paboeuf.institutoptique.fr.

Sponsored Recommendations

March 31, 2025
Enhance your remote sensing capabilities with Chroma's precision-engineered optical filters, designed for applications such as environmental monitoring, geospatial mapping, and...
March 31, 2025
Designed for compatibility with a wide range of systems, Chroma's UV filters are engineered to feature high transmission, superior out-of-band blocking, steep edge transitions...
March 31, 2025
Discover strategies to balance component performance and system design, reducing development time and costs while maximizing efficiency.
March 31, 2025
Explore the essential role of optical filters in enhancing Raman spectroscopy measurements including the various filter types and their applications in improving signal-to-noise...

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!