InGaAsP/InP optical switches embedded with semi-insulating InP current blocking layers

A carrier injection type of InGaAsP/InP optical switch is fabricated using a semi-insulating InP current blocking layer. The switching state is obtained by current injection of 180-1000 mA. The lifetime of the injection carrier is calculated to be 6.8 ns from the measurement of switching delay time. On the basis of these fundamental switching characteristics, the reduction of the operation current and the improvement of the modulation bandwidth are theoretically investigated. It is shown that the operation current as low as 3 mA will be attained for the switch with a 6° crossing angle and that high-speed operation up to 2 GHz will be achieved by increasing the doping level in the core layer. It is also shown that an optical switch with a crossing angle over 15° will be realized for this type of semiconductor switch