Beam combinable, kilowatt all-fiber amplifiers for directed energy

Beam combinable, kilowatt all-fiber amplifiers for directed energy

For access to this article, please select a purchase option:

Buy chapter PDF
(plus tax if applicable)
Buy Knowledge Pack
10 chapters for $120.00
(plus taxes if applicable)

IET members benefit from discounts to all IET publications and free access to E&T Magazine. If you are an IET member, log in to your account and the discounts will automatically be applied.

Learn more about IET membership 

Recommend Title Publication to library

You must fill out fields marked with: *

Librarian details
Your details
Why are you recommending this title?
Select reason:
Advances in High-Power Fiber and Diode Laser Engineering — Recommend this title to your library

Thank you

Your recommendation has been sent to your librarian.

In this chapter, several beam combining architectures suitable for DE applications have been reported, and are divided into two distinct categories: incoherent beam combination (IBC) and coherent beam combination (CBC). The purpose of each method is to increase the far field intensity when brightness and power of a single fiber amplifier is limited. In IBC, an array of fiber lasers is superimposed in the far field without control of the relative spectra or phases of the different fibers. No brightness enhancement is obtained from this method, limiting the maximum intensity in the far field. Although such beam combining has been successfully demonstrated by the Navy [5], this approach is limited to propagation ranges on the order of a few kilometers. In spectral beam combining (SBC), a separate class of IBC, incoherent beams of different wavelengths are spatially overlapped to create a single output beam of multiple colors. The brightness of the propagating beam can be increased at the cost of increased spectral bandwidth. Similarly, SBC has the advantage of not requiring active phase control or mutual temporal coherence of the individual beams. Alternatively, coherent beam combining (CBC) schemes require proper phase, frequency, and polarization relationships for efficient beam combination. Overall, due to their brightness enhancements, for longer range and higher power/ intensity DE applications, SBC and CBC are potentially more appealing.

Chapter Contents:

  • 9.1 Introduction
  • 9.2 Time-dependent nonlinear SBS theory and model
  • 9.3 Phase modulation in kW class all-fiber amplifiers
  • 9.3.1 WNS and PRBS SBS suppression comparison
  • 9.3.2 WNS and PRBS coherent beam combining analysis
  • 9.3.3 Filtered PRBS phase modulation
  • Filtered PRBS: coherent combining
  • Filtered PRBS: SBS suppression
  • 9.3.4 PRBS re-coherence
  • 9.4 Multi-kW coherent beam combining of PRBS modulated fiber amplifiers
  • 9.5 Laser gain competition of all-fiber amplifiers
  • 9.5.1 Laser gain competition (two-tone): power scaling
  • 9.5.2 Laser gain competition (two-tone): beam combining
  • 9.6 Conclusion
  • Acknowledgments
  • References

Inspec keywords: laser beam applications; optical fibre amplifiers; laser beams

Other keywords: incoherent beam combination; DE applications; spectral bandwidth; coherent beam combination; single fiber amplifier; spectral beam combining; brightness enhancements; kilowatt all-fiber amplifiers; directed energy; far field intensity; fiber lasers

Subjects: Design of specific laser systems; Laser applications; Textbooks; Laser beam interactions and properties; Laser applications; Fibre lasers and amplifiers; Laser beam characteristics and interactions; Fibre lasers and amplifiers

Preview this chapter:
Zoom in

Beam combinable, kilowatt all-fiber amplifiers for directed energy, Page 1 of 2

| /docserver/preview/fulltext/books/cs/pbcs054e/PBCS054E_ch9-1.gif /docserver/preview/fulltext/books/cs/pbcs054e/PBCS054E_ch9-2.gif

Related content

This is a required field
Please enter a valid email address