Few-mode YAG Crystal Fiber Cladded by High-index Glass

Single crystalline YAG-core fiber with a lanthanum dense flint glass cladding

“…We already used the N-SF57 glass with its refractive index close to but slightly lower than that of YAG for cladding YAG crystal fiber core using the CD-LHPG process. A phenomenally large index drop of the N-SF57 cladding of at least 0.02 was found compared with the nominal index of N-SF57 [5]. The large index drop of the cladding glass during CD-LHPG should be taken into consideration when choosing the proper cladding glass.…”

“…For achieving small positive Δn between the YAG crystal core and the glass cladding, the glass cladding material should be chosen to have a small but negative pre-CD-LHPG Δn, considering the expected significant index drop induced by the CD-LHPG process [5]. The N-LaSF9 glass having an index higher than that of YAG crystal, as shown in Fig.…”