20-Gb/s ON–OFF-Keying Modulators Using 0.25- $\mu$ m InP DHBT Switches at 290 GHz.

Performances of high-speed switches operating as terahertz on–off-keying (OOK) modulators are reported. Two types of switches, a passive shunt switch and an amplifier switch, are fabricated using 0.25- $\mu \text{m}$ InP double heterojuction bipolar transistor (DHBT) technology. Small-signal tests show that the amplifier switch possesses superior on–off ratio, but the passive switch has broader bandwidth and smaller group delay ripples. A modulator test setup is built with 20-dB path loss between the transmitter and the receiver. The results indicate that carrier power levels of 14 dBm for the shunt switch and 8 dBm for the amplifier switch are required for 20-Gb/s OOK modulation with bit error rate (BER) of 10−2 at 290 GHz. [ABSTRACT FROM AUTHOR]