Research

Professor Marciante's research group is currently focused on large-mode area fibers, high-efficiency fiber amplifiers, visible fiber lasers, high-brightness semiconductor lasers, ans spatially-coherent beam combination.

The word cloud generated from our journal paper titles is shown below (courtesy of Wordle): click for full-scale image

A few of our current projects are listed below.  Please also refer to our recent publications.


High Brightness Semiconductor Lasers

Broad-area laser (BAL) diodes are useful for pumping high-power fiber lasers and amplifiers, however they suffer greatly due to free-carrier induced self-focusing causing beam filamentation and thus reduced beam quality.

We are exploring methods of on-chip, integrated, continuous filtering in order to suppress filamentation in broad-area lasers in order to relieve the pumping limitations on high-power fiber lasers/amplifiers that BALs impose.  We are using a custom Beam Propagation Method code to design gain, current, and index structures that preferentially and continuously filter the high spatial frequency light characteristics of filamentation before it experiences large amounts of gain.

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Fiber Lasers at Exotic Wavelengths

High-power, high-brightness, solid-state coherent light sources in the visible wavelengths are of great interest in laser material processing, home entertainment, opthamology, and much more. Fiber lasers excel in their power scaling ability and beam quality. However, most visible fiber lasers are based on fluorozirconate fibers which suffer from brittleness and hygroscopy. It is highly desirable to realize visible lasing in silica fibers, which are compatible with the established technology and components developed with the telecommunications industry.

We are studying exotic dopants in silicate fibers which potentially allow lasing at multiple visible wavelengths in one device. Current efforts encompass experimental characterization of fibers with such dopants, numerical simulation of its laser properties, and fabrication of fibers with novel designs.


Large-Mode-Area Fiber Lasers

High power and high pulse energy fiber lasers and amplifiers require large-mode area fibers to spread the optical power and reduce the optical intensity to avoid detrimental noniear effects, such as stimulated Brillouin scattering.  However, modal discrimination in large-mode-area fibers becomes increasingly difficult with increasing core area.  Moreover, thermal effects such as mode compression and thermal mode instability further inhibit core-area scaling.

We are developing multiple types of fibers to mitiage these problems and enable core-are scaling while maintaining good beam quality.  Such fiber types include semi-guiding high-aspect-ratio-core (SHARC) fiber, confined-gain fiber to exploit gain filtering, and other unique designs including spatial index and gain tailoring.

© John Marciante 2017