Kevin Creedon
Massachusetts Institute of Technology
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Featured researches published by Kevin Creedon.
Optics Letters | 2011
Shawn Redmond; Kevin Creedon; Jan E. Kansky; Steven J. Augst; Leo J. Missaggia; Michael K. Connors; Robin K. Huang; Bien Chann; Tso Yee Fan; George W. Turner; Antonio Sanchez-Rubio
We have demonstrated active coherent beam combination (CBC) of up to 218 semiconductor amplifiers with 38.5 W cw output using up to eleven one-dimensional 21-element individually addressable diode amplifier arrays operating at 960 nm. The amplifier array elements are slab-coupled-optical-waveguide semiconductor amplifiers (SCOWAs) set up in a master-oscillator-power-amplifier configuration. Diffractive optical elements divide the master-oscillator beam to seed multiple arrays of SCOWAs. A SCOWA was phase actuated by adjusting the drive current to each element and controlled using a stochastic-parallel-gradient-descent (SPGD) algorithm for the active CBC. The SPGD is a hill-climbing algorithm that maximizes on-axis intensity in the far field, providing phase locking without needing a reference beam.
Optics Letters | 2012
Kevin Creedon; Shawn Redmond; Gary M. Smith; Leo J. Missaggia; Michael K. Connors; Jan E. Kansky; Tso Yee Fan; George W. Turner; Antonio Sanchez-Rubio
We demonstrate 40 W coherently combined output power in a single diffraction-limited beam from a one-dimensional 47-element array of angled-facet slab-coupled optical waveguide amplifiers at 1064 nm. The output from each emitter was collimated and overlapped onto a diffractive optical element combiner using a common transform lens. Phase locking was achieved via active feedback on each amplifiers drive current to maximize the power in the combined beam. The combining efficiency at all current levels was nearly constant at 87%.
Applied Optics | 2012
Juan Montoya; Steven J. Augst; Kevin Creedon; Jan E. Kansky; Tso Yee Fan; Antonio Sanchez-Rubio
Active coherent beam combining of laser oscillators is an attractive way to achieve high output power in a diffraction limited beam. Here we describe an active beam combining system used to coherently combine 21 semiconductor laser elements with an 81% beam combining efficiency in an external cavity configuration compared with an upper limit of 90% efficiency in the particular configuration of the experiment. Our beam combining system utilizes a stochastic parallel gradient descent (SPGD) algorithm for active phase control. This work demonstrates that active beam combining is not subject to the scaling limits imposed on passive-phasing systems.
Proceedings of SPIE | 2016
Leo J. Missaggia; C. A. Wang; Michael K. Connors; Brian G. Saar; Antonio Sanchez-Rubio; Kevin Creedon; George W. Turner; William D. Herzog
There are a number of military and commercial applications for high-power laser systems in the mid-to-long-infrared wavelength range. By virtue of their demonstrated watt-level performance and wavelength diversity, quantum cascade laser (QCL) and amplifier devices are an excellent choice of emitter for those applications. To realize the power levels of interest, beam combining of arrays of these emitters is required and as a result, array technology must be developed. With this in mind, packaging and thermal management strategies were developed to facilitate the demonstration of a monolithic QCL array operating under CW conditions. Thermal models were constructed and simulations performed to determine the effect of parameters such as array-element ridge width and pitch on gain region temperature rise. The results of the simulations were considered in determining an appropriate QCL array configuration. State-of-the-art micro-impingement cooling along with an electrical distribution scheme comprised of AlN multi-layer technology were integrated into the design. The design of the module allows for individual electrical addressability of the array elements, a method of phase control demonstrated previously for coherent beam combining of diode arrays, along with access to both front and rear facets. Hence, both laser and single-pass amplifier arrays can be accommodated. A module was realized containing a 5 mm cavity length monolithic QCL array comprised of 7 elements on 450 m pitch. An output power of 3.16 W was demonstrated under CW conditions at an emission wavelength of 9μm.
Proceedings of SPIE | 2012
Gary M. Smith; J.P. Donnelly; Leo J. Missaggia; Michael K. Connors; Shawn Redmond; Kevin Creedon; D.C. Mathewson; Reuel B. Swint; Antonio Sanchez-Rubio; George W. Turner
Slab-coupled optical waveguide lasers (SCOWLs) and amplifiers (SCOWAs) are inherently low-confinement structures with large nearly-circular modes that are easily coupled to optical fibers or collimated for free-space applications. Recently SCOWL powers have increased to 3 W by increasing the cavity length to 1 cm and improving the heat removal. SCOWAs are coherently combined using active phase control to achieve a very high-brightness source. Our coherent beam combining system consists of single-pass amplifiers with angled-facet SCOWAs that suppress feedback. Single-pass, 5-mm long, SCOWAs have now been demonstrated with 1.5 W CW output with only 50 mW seed power. Arrays of 47 SCOWAs have demonstrated a raw power of 57 W with 50 mW of seed power per element. A coherent beam combining demonstration is currently being assembled.
Applied Physics Letters | 2015
Juan Montoya; Christine Y. Wang; Anish K. Goyal; Kevin Creedon; Michael K. Connors; Jeffrey Daulton; J.P. Donnelly; Leo J. Missaggia; Chris Aleshire; Antonio Sanchez-Rubio; William D. Herzog
We report on monolithic integration of active quantum cascade laser (QCL) materials with passive waveguides formed by using proton implantation. Proton implantation reduces the electron concentration in the QCL layers by creating deep levels that trap carriers. This strongly reduces the intersubband absorption and the free-carrier absorption in the gain region and surrounding layers, thus significantly reducing optical loss. We have measured loss as low as α = 0.33 cm−1 in λ = 9.6 μm wavelength proton-implanted QCL material. We have also demonstrated lasing in active-passive integrated waveguides. This simple integration technique is anticipated to enable low-cost fabrication in infrared photonic integrated circuits in the mid-infrared (λ ∼ 3–16 μm).
conference on lasers and electro optics | 2014
Juan Montoya; Steven J. Augst; Kevin Creedon; Jan E. Kansky; Antonio Sanchez-Rubio; T. Y. Fan
Beam combining of a laser array allows power scaling with increased brightness. Here we report 27 W of coherently combined power from 9 solid-state intracavity gain elements with a combining efficiency of 87%.
conference on lasers and electro optics | 2013
Kevin Anglin; Kevin Creedon; Adam Hanninen; Michael K. Connors; Leo J. Missaggia; Jeanne Porter; George W. Turner; Antonio Sanchez-Rubio; William D. Goodhue; Reuel B. Swint
A surface-emitting SCOWL is demonstrated using a deep etched 45° turning mirror, achieving 1 W q-CW output power, a diffraction-limited beam, and comparable efficiency to conventional edge-emitters. This design offers 2-D laser array scalability.
photonics society summer topical meeting series | 2012
Gary M. Smith; Shawn Redmond; J.P. Donnelly; Leo J. Missaggia; Michael K. Connors; Kevin Creedon; D.C. Mathewson; Reuel B. Swint; Antonio Sanchez-Rubio; George W. Turner
SCOWAs have produced 1.5 W of output power with a 44 mW seed. Arrays of 47 SCOWA elements have demonstrated a raw power of 57 W. Coherent beam combining of these arrays will be discussed.
conference on lasers and electro optics | 2012
Steven J. Augst; Juan Montoya; Kevin Creedon; Jan E. Kansky; T. Y. Fan; Antonio Sanchez-Rubio