Fig. 4. Multimode waveguides fabricated by MPP.
a SEM image of multimode waveguides with the widths ranging from 3 µm to 10 μm (from left to right). b, c Microscope images of areas close to the ends of the waveguides (wl = 10 μm), where the sample was cleaved. The output signal from one end of the waveguide is imaged by a CCD camera. d Microscope images of waveguides fabricated on a glass substrate by stitching eight parallel waveguide sections shown in (a). e Enlarged view of the stitching area where the photosensitive material was exposed twice. The width of the waveguide is 8 µm. The length of the stitching area is approximately 25 µm. f Bright-field microscope image of light guided through the waveguide (width: 10 µm). The doubly exposed area does not affect the propagation of light in the waveguide. g Long waveguides on a flexible PMMA substrate obtained by stitching eight parallel waveguide sections shown in (a). The length of each waveguide is approximately 1.2 cm. h Image of the long waveguides when bent.