KEYWORDS: Fiber lasers, Adaptive control, Process control, Single mode fibers, Control systems, Modulators, Laser applications, High power fiber lasers
In this paper, the adaptive mode control method based on a 6-port photonic lantern is presented. The structural characteristics of the photonic lantern were introduced, and the control mechanism from multi-single mode to super mode in the photonic lanterns were analyzed. The mode control experiments with the 6-port photonic lantern were conducted. We demonstrate that quasi-single mode can be achieved in large-mode field fiber by adaptively control the phase and intensity in the input ports of the photonic lantern. The output beam power in bucket (PIB) can be increased from 37% to 63%.
Photonic lanterns can control beam modes by tuning phase, amplitude and polarization of multiple beam inputs, providing new methods to overcome mode instability in high-power large-mode area fiber lasers. The initial amplitude input of photonic lanterns are usually preset to be equal or random. The beam mode is then adaptively controlled by evaluating the beam output profile. This method can easily realize stable light output, but it sometimes runs into local optimum solutions. In this work, we propose a novel method to preset the initial amplitudes to realize better beam mode control. Based on the waveguide characteristics of the photonic lantern structure, we inversely work out the initial amplitude requirement of the input channels for controlling a certain mode using its transmission matrix. Taking 3×1 photonic lantern as an example, our simulation results show that this method can realize any mode control of LP01, LP11e, LP11o with their mode power ratios all above 99%, better than those preset methods to be equal or random. Our simulation method can be utilized in beam control experiments to achieve better beam control in photonic lantern-based fiber lasers
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.