Jan 27 2009
Alfalight, Inc., a leading supplier of highly efficient high-power diode lasers, announced today the first details of its breakthrough Surface-Emitting Distributed Feedback (SE-DFB) laser diode technology. This technology uses a significantly different approach at the wafer level to provide a lower-cost system solution with enhanced brightness and ruggedness compared to the edge-emitting laser technology.
Key features include complete immunity to facet damage, on-chip integrated wavelength stabilization, and intrinsically high brightness that eliminates the need for expensive, precision optical elements. The company will provide details at an invited presentation scheduled for Thursday, January 29 at the Photonics West 2009 conference in San Jose, CA, by Manoj Kanskar, vice president, Research and Development at Alfalight. The talk will describe SE-DFB technology, discuss experimental results, and outline configurations for combining chips into high power laser arrays. Prototype SE-DFB chips, and demonstrations of a SE-DFB-based array and a fiber-coupled module are on display at the Alfalight booth at Photonics West (booth 443).
"Alfalight's SE-DFB laser is a breakthrough technology that will reach beyond the capabilities of bar-based optical sources. We are introducing a new approach to high power semiconductor lasers that will provide cost-competitive, robust and high brightness diode laser systems that will benefit fiber lasers, solid state lasers and direct diode applications," said Manoj Kanskar. "SE-DFB lasers have unmatched power scaling and wavelength stabilization capability besides a singular brightness advantage over edge-emitting laser diodes. This technology has the potential to displace ubiquitous laser diode bars in many important applications."
Highlights of SE-DFB Technology
SE-DFB lasers are made of the same high-reliability semiconductor material used for Alfalight's edge-emitting lasers. Whereas standard edge-emitting lasers emit through a small facet on the edge of the semiconductor chip, SE-DFB lasers emit through a large optical window on the surface of the laser chip. A curved grating patterned on the base layer of the semiconductor chip has four main functions:
- To form the laser cavity, providing optical feedback precisely at the design wavelength, locking the emission spectrum on a narrow peak for any combination of operating temperatures and currents
- To couple the laser beam out of the laser chip, through an AR-coated optical window while collimating it in one direction without the aid of external optics
- To shape the optical wavefront to enhance brightness and suppress filamentation
- To protect the device from external optical feedback
The optical density at the emission window of a SE-DFB laser is four orders of magnitude lower than at the facet of edge-emitting lasers, making SE-DFB lasers immune to Catastrophic Optical Mirror Damage (COMD), the main reliability issue plaguing current laser diode technology.
Several SE-DFB laser chips can be combined on a common heat sink and coupled into an optical fiber using simple optical elements. No micro-lenses or beam transformation optics are needed.
SE-DFB lasers offer the same 0.07 nm/°C wavelength stability as Alfalight's proven Wavelength Stabilization Technology (WST) -- a factor of five more stable over temperature than standard semiconductor lasers. Consequently, there is no need to precisely control the temperature of the SE-DFB laser chip. SE-DFB diodes can be driven by low-current power supplies, further reducing system costs.
Alfalight anticipates the technology will benefit applications such as pumping of high power fiber lasers and solid-state lasers, as well as direct diode applications such as materials processing, and IR illumination. For information about Alfalight's high-power laser diode pump sources, please contact Anthony Bisco at [email protected] or +1-608-240-4826.