Eye-safe broadband output at 1.55 microns through the use of a fan-out grating structure in MgO:PPLN

J A C Terry, G Tsiminis, Malcolm Harry Dunn, Cameron Francis Rae

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3 Citations (Scopus)


Attempts at active imaging employing narrowband sources suffer from reduction in image fidelity due to the presence of speckle. Use of broadband sources promises to alleviate this problem. Here we report the demonstration of > 1.5 W of broadband (> 20 nm, full width at 1/e(2) points (fw1/e(2))) 1.55 mu m output from an optical parametric oscillator (OPO) utilizing a fan-out grating structure in MgO doped with periodically poled lithium niobate (PPLN). Anamorphic expansion of the pump beam (diode-pumped Nd:YVO4 Q-switched at 25 kHz) in the plane of the fan provides for control of the bandwidth of the output. Operation was achieved with both plano-concave and plane-plane OPO resonators, with best performance (bandwidth, efficiency and beam quality) achieved under plane-plane conditions. The maximum output power of similar to 1.6 W was achieved for a pump power of 5.2 W: an efficiency of 30%. Structure in the spectra was observed, which led to the conclusion that rather than the grating period varying continuously, it is believed to consist of small steps in the period.
Original languageEnglish
Pages (from-to)229-234
Number of pages6
JournalJournal of Optics A: Pure and Applied Optics
Issue number3
Publication statusPublished - Mar 2007


  • OPO
  • fan-out grating
  • PPLN
  • broadband
  • eye-safe
  • LINBO3


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