Abstract
Coherent beam combining can be used to scale optical power and enable mechanism-free beam steering using an optical phased array. Coherently combining multiple free-running lasers in a leader-follower laser configuration is challenging due to the need to measure and stabilize large and highly dynamic phase differences between them. We present a scalable technique based on frequency-offset phase locking and digitally enhanced interferometry to clone the coherence of multiple lasers without the use of external sampling optics, which has the potential to support both coherent and spectral beam combining, and alleviates issues of voltage wrapping associated with actuating feedback control using electro-optic modulators. This technique was demonstrated experimentally using a tiled-aperture optical phased array in which the relative output phase of three free-running lasers was stabilized with an RMS output phase stability of λ/104.
Highlights
Optical phased arrays (OPAs) manipulate the distribution of optical power in the far field by controlling the phase of light emitted by multiple spatially separate transmit apertures
The first is split into multiple channel, each connected to a waveguide electro-optic modulator used to encode the phase of the light with a pseudo-random bit sequence (PRBS) for digitally enhanced heterodyne interferometry [22]
We have presented a technique for coherently combining multiple free-running follower lasers based on frequency-offset phase locking
Summary
Optical phased arrays (OPAs) manipulate the distribution of optical power in the far field by controlling the phase of light emitted by multiple spatially separate transmit apertures. By precisely controlling the relative optical phase at the output of the array, OPAs can be used to deliver a large amount of optical power to a specific location in the far-field (e.g., for directed energy applications [1]); and rapidly steer the interfered beam within its field-of-regard without the use of moving parts (e.g., for solid-state light detection and ranging (LiDAR) [2], adaptive optics [3], free-space laser communications [4], satellite interferometry [5], and materials processing [6]). [14]) to actively stabilize the relative phase of multiple independent follower lasers to a single free-running leader laser at a specific offset frequency. We refer to this as a leader-follower laser configuration. One advantage of this architecture is the ability to arbitrarily define the offset frequencies between follower lasers, enabling it to support both coherent and spectral beam-combining
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
