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We investigate the cause of the insertion loss of our holographic switch by determining the relation between the diffraction efficiency and the hologram patterns generated by the control beams. According to the calculation the theoretical insertion loss is 7.4 dB with loss distribution of 0.03 dB under the conditions of a previous experiment. We find that incomplete storage of the interference pattern on the optically addressed spatial light modulator is the strongest factor determining the insertion loss.

We have proposed a holographic switch with a ferroelectric liquid-crystal spatial light modulator for a large-scale switch. 4 × 1204 switching was demonstrated to show that the proposed switch structure is suitable for a large-scale switch. The average losses of the four inputs were 28, 33, 35, and 36 dB. The average crosstalk-to-signal ratio of one of the inputs was-16 dB.

• Effects of defibrinogenation therapy and steroid therapy for sudden deafness were compared by paired double-blind testing. The average hearing recovery for five frequencies (250 to 4000 Hz) was more than 30 dB; overall improvement rate was 57.3% (47/82) for the patients assigned to defibrinogenation therapy and 38.7% (31/80) for the patients assigned to steroid therapy. Thus, the former treatment resulted in significantly better hearing recovery.(Arch Otolaryngol Head Neck Surg 1988;114:649-652)

We extended the scale of a previously reported holographic switch [Appl. Opt.34, 8137 (1995)] in which each input is assigned to one of the control light sources to control a large-scale switch with low power. The average losses of the four inputs were 28, 33, 35, and 36 dB. The average cross-talk-to-signal ratio of one of the inputs was -16 dB.

We demonstrate 1 × 1104 holographic switching with a ferroelectric liquid-crystal spatial light modulator to test the feasible output size of a holographic switch. The demonstration proves that switching was achieved when the power of a laser diode used as the control light source was 6.3 mW. The average of the insertion loss was 31.6 dB.