An intersectional optical switch structure based on the field induced refractive index variation was fabricated by the use of LPE grown GaInAsP/InP MQW wafer. The first switching operation in a MQW intersectional switch structure was achieved. The field induced refractive index variation in quantum well was estimated to be around 0.45% at the applied field of 13 V/µm from the experimentally obtained switching ratio. Finally a small X-type modulator with low chirp, low power saturation is proposed which make use of the reflection phenomenon caused by field induced rafractive index variation instead of absorption phenomenon as in conventional absorption type modulators.

Field induced refractive index variation and the ratio of index to loss variations p' which is an important parameter deciding the loss characteristics of an intersectional optical switch, was analyzed for GaInAs/InP quantum box structure. We found that large index variation and large | p| value(10) with low fundamental absorption, which are required for low insertion loss switch(1 dB), can be attained. Further the usable wavelength range for low loss switching operation is shown to be around 8 nm.