Scalable Phase Locking of Large High Power Semiconductor Diode Arrays
Abstract
A wide variety of Navy applications requires laser sources that are capable of emitting very high powers with excellent quality beam,. For many applications, a single laser cannot provide such a power thus beam combining of multiple lasers is being employed. Scalab,le phase locking of lasers is considered one of the most important though challenging and yet unsolved problems in directed energy.,A variety of external cavity designs (such as Talbot, Fourier, V-Shape Talbot, etc.) have been explored; however, so far scalable ph,ase locking of large diode arrays has not been demonstrated. External cavity designs, if successful, would allow for spontaneous pha,se locking of large number of diode lasers thus would substantially decrease the complexity of high-power laser system design. Spont,aneous phase locking can be achieved by coupling the emitted radiation among the diodes in the array. Experimental results show almo,st perfect diffraction-limited beams emitted from small, high-power, commercial quality broad-area diode arrays. The main questions,though remain: (a) is it possible to phase lock large arrays of semiconductor diode and, if yes, (b) how and what are the mechanis,ms of robust and scalable phase locking of large high-power semiconductor (or other lasers) diode arrays? Recently, the feasibility,of achieving scalable phase locking in very large, electromagnetically coupled single-mode diode arrays has been reported, based on,theoretical and computational results. It has been shown that, for properly designed laser coupling structure, a stable spatial mode, can be formed and result in almost perfect phase locking of the array. Existence and stability of such a mode does not vanish with,the array size, consequently very large arrays may possess such spatial mode behavior leading to almost perfect phase locking.The go,al of the project is to develop fundamental paradigms by which we can design coherent beam combining of semiconductor diode laser sy,stems, computationally test the proposed phase locking mechanisms on very large two-dimensional arrays, and experimentally test the,phase locking and fundamental phase locking paradigms. Our group is capable of fabricating high power (of the order of 5-10W) single,-mode diodes and diode arrays, consequently, the proposed phase locking mechanisms will be tested using the arrays fabricated at CRE,OL. We will be utilizing phase locking mechanisms that either (a) are robust to effects of heterogeneity, misalignment, and multiple, transverse modes or (b) use one or more of these detrimental effects in ways that are advantageous to maintaining a robust diffract,ion-limited beam from the array of lasers. We would like to design and study fundamental paradigms for passive coherent beam combini,ng of large arrays of semiconductor lasers that are specifically robust to the effects of large amounts of heterogeneity among eleme,nts (e.g. ~GHz detunings), misaligned facets, and existence of multiple transverse and longitudinal modes in the lasers. We would sp,ecifically like to find and exploit dynamical mechanisms by which disorder in the system could be used to strengthen (rather than de,stabilize) coherent behavior.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 05, 2022
- Source ID
- N000142212237
Entities
People
- Y. Braiman
Organizations
- Office of Naval Research
- United States Navy
- University of Central Florida Board of Trustees