10,976 research outputs found
Current noise in resonance tunnel diodes based on InGaAlAs heterostructures
Noise in resonance tunnel diodes based on InGaAlAs structures is studied at two frequencies. A
shot noise caused by the current flowing through two barriers of the heterostructure is identified. It was found
that if the voltage across the structure is within the first ascending section of the current–voltage characteristics,
the shot noise is suppressed with the suppression ratio
G
~ 1/15. In the second ascending section of the current–
voltage characteristic, the shot noise coincides with the shot noise of electrons passing through one barrier
(
G = 1) by the order of magnitude. The specific features of current flow affecting the behavior of noise in the
resonance tunnel structures are discussed
Optoelectronic oscillators for communication systems
We introduce and report recent developments on a novel five port optoelectronic voltage controlled oscillator consisting of a resonant tunneling diode (RTD) optical-waveguide integrated with a laser diode. The RTD-based optoelectronic oscillator (OEO) has both optical and electrical input and output ports, with the fifth port allowing voltage control. The RTD-OEO locks to reference radio-frequency (RF) sources by either optical or electrical injection
locking techniques allowing remote synchronization, eliminating the need of
impedance matching between traditional RF oscillators. RTD-OEO functions include generation, amplification and distribution of RF carriers, clock recovery, carrier recovery, modulation and demodulation and frequency synthesis. Self-injection locking operation modes, where small portions of the output electrical/ optical signals are fed back into the electrical/optical input ports, are also proposed. The self-phase locked loop configuration can give rise to low-noise high-stable oscillations, not limited by the RF source performance and with no need of external optoelectronic conversion
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