**4.2.1 Splicing IPHT 282b4 to SMF**

Being similar to SMF, this fibre was spliced in the same way, using the following fusion program (pre-fusion, fusion, annealing - Figure 4): 9 mA – 3 s / 17 mA – 0.5 s / 9 mA – 3 s.

PCF length, attenuation and loss at 1558 nm were 12.4 m, 61.5 dB/km and 0.76 dB respectively. The SMF fibre was Corning SMF-28 (Corning, 2008). Splice loss (Table 3) was acceptable despite destruction of photonic structure over 300 µm (Figures 24 and 25), due to guiding of light by doped core. This case was easy, as no special techniques were required besides reduction of fusion power and duration in comparison to SMF splicing. Lower loss was achievable with shorter fusion time, but at expense of reduced splice strength.

Fig. 24. SMF (left) and PCF (right) cleaved and positioned before fusion.

Fig. 25. Fibres fused.


Table 3. Loss of IPHT 282b4 sample measured during making of splice No. 2 (1558 nm).
