A novel optically-triggered (OT) interband resonant-tunneling-diode (I-RTD) device (based on AlGaSb/InAs/AlGaSb
heterostructures) concept for generating terahertz (THz) frequency oscillations has been previously presented that shows
promise for achieving enhanced output power levels under pulsed operation. The main concept is to utilize novel
nanoscale mechanisms to achieve an externally driven relaxation oscillation that consists of two phases. Namely, the
first phase is a valence band (VB) well hole-charging transient produced by a natural Zener (interband) tunneling
process and the second is a discharging transient induced by optical annihilation of the VB well hole-charge by
externally-injected photon flux. While the initial simulation results for a practical diode-laser implementation clearly
show the superiority of this new oscillator concept (i.e., excellent output power capability, ~10mW, over broad portions
of the THz regime, ~300-600GHz), the specific optical-triggering conditions required by the AlGaSb/InAs based
material systems (i.e., photonic-energy ~4.7 μm, intensity level ~3.5x107 W/cm2 and a pulse repetition frequency (PRF)
equal to the THz oscillation period) are technically too demanding to meet for continuous-wave (CW) mode operation.
Hence, this paper will report on variations and extensions of the original OT-I-RTD oscillator concept. Specifically,
modifications to the device structure will be considered to allow for OT operation at 1.55 μm where the optical
technology is more robust. Here the specific focus will be in the introduction of In1-xGaxAs /GaSbyAs1-y hetero-systems
and the application of band-engineering to assess the potential of a 1.55 μm based OT-I-RTD oscillator design.