Every other one optical fiber core regarded as a positioning fixture was removed from the glass substrate; thus the 1st layer of optical fiber cores with nominal pitch 250 [micro]m was formed.
The aforementioned construction process was repeated and every other two neighboring optical fiber cores regarded as positioning fixtures were removed; likewise, the 3D arrays of 2 and 3 layers of optical fiber cores with nominal pitch 375 [micro]m were formed, respectively
The averages of the actual pitches of the 3D array of the cylindrically hierarchical structures in Figure 2(a) deviated less from nominal pitch 250 than that in Figure 2(d) from nominal pitch 375 [micro]m.
Similarly, the ZnO seed solution was deposited on the aforementioned 3D arrays of 2 and 3 layers of optical fiber cores with nominal pitches 250 [micro]m and 375 [micro]m.
Figure 2 demonstrates the 3D arrays of 2 and 3 layers of cylindrically hierarchical structures with nominal pitches 250 [micro]m and 375 [micro]m.