Page 127 - Fiber Bragg Gratings
P. 127

Table 3.1: Common options of UV laser sources for grating formation.

                            UV wavelength          UV
           Pump laser            (nm)         power/energy      Beam shape       Beam quality      Application
           KrF              248              1 J/lOOHz, QS    Few cm diameter   Low spatial/     Mass production,
                                                                                 temporal coher-   fiber drawing
                                                                                 ence: requires    tower grating
                                                                                 injection lock-   fabrication,
                                                                                 ing               TYPE II grat-
                                                                                                   ings
           ArF              193              1 J(lOOHz) QS    Few cm diameter   Low spatial/     Planar devices,
                                                                                 temporal coher-   non-Ge
                                                                                 ence              fibers/planar,
                                                                                                   direct writing
           Quadrupled       266, KDP/BBO     >100 mW 5 ns     1 mm diameter     10 mm coherence  Hydrogen loaded
            Nd:YAG (1064      frequency dou-   QS pulses at                      length, low       fibers, planar
            nm)               biers            >lkHz                             transverse        Ge/P doped sil-
                                                                                 beam coher-       ica, + RE-
                                                                                 ence              doped silica,
                                                                                                   Type II grat-
                                                                                                   ings
           Nd:YAG (355 nm   220-260 tunable  >100 mW, 4 ns    2 mm diameter,    Low coherence,   UV-induced
            via frequency     extra cavity     QS               not Gaussian,    unless line-      index change
            mixing)           BBO frequency                     flat-topped or   narrowed          studies, grat-
                              doubled                           triangular                         ing writing,
                                                                                                   material stud-
                                                                                                   ies, Type II
                                                                                                   grating forma-
                                                                                                   tion, scanned
                                                                                                   phase mask
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