This paper describes a newly developed 22 liquid crystal optical switch for 1.3µm single-mode fiber use. This switch state can be freely set at either the cross or the bar state. The measured performance of two prototype 22 liquid crystal optical switches is given. Tests confirm that the 3 values are a maximum insertion loss of 1.5dB, a crosstalk attenuation of more than 26.1dB, and a return loss of more than 28.9dB. Requirements for optical switches for fault isolation are theoretically clarified from a LAN system view point.