Fig. 1. Principle of the optical attenuator: (a) initial state; (b) loading a grayscale with phase π on the SLM.

Fig. 2. Phase modulation of the SLM when loading different grayscales.

Fig. 3. Results of loading different grayscales on the SLM: (a) value=0; (b) value=15; (c) value=30; (d) value=45; (e) value=60; (f) value=75 (Media 1).

Fig. 4. Attenuation when loading different grayscales on the SLM.

Fig. 5. Structure of the extended 1×2 optical switch.

Fig. 6. Grayscales loaded on the SLM and the results of light-on and light-off: (a) grayscale in (1, 1) state; (b) grayscale in (1, 0) state; (c) result of (1, 1) state; (d) result of (1, 0) state.