Horacio I. Cantú

Delayed Feedback Dynamics of Liénard-Type Resonant Tunneling-Photo-Detector Optoelectronic Oscillators

We use the nonlinear dynamics approach for studying delayed feedback optoelectronic oscillators (OEOs) formed by hybrid integration of resonant tunneling diode (RTD) photo-detectors with laser diodes, in both single and dual optical fiber feedback routes. In the single loop topology, the performance of the RTD-OEO free-running self-sustained oscillator is improved in terms of phase noise, with a compromise between the delay line and the strength of the optical re-injection. In the dual-loop configuration, superior performance is achieved due to the suppression of the side modes associated with the optical cavity length, resulting in a side mode suppression ratio of up to -60 dBc of the carrier frequency. We compare experimental results with numerical simulations based on a system of delay differential equations comprising a Liénard oscillator model driven by white Gaussian noise and coupled with laser rate equations. The delayed feedback Liénard oscillator model gives considerable insight into the RTD-OEO dynamical regimes predicting its main features in both single- and dual-loop configurations.

Resonant Tunneling Diode Optoelectronic Circuits Applications in Radio-Over-Fiber Networks

Phase-locked oscillators based on resonant tunneling diodes are used in this study to implement transceiver components that perform conversion between optical and wireless phase shift-keyed signals using injection-locked oscillator techniques. Three different links are demonstrated at frequencies of 940 MHz, 1.3 GHz, and 3.2 GHz that are capable of locking to a phase-modulated signal that propagates from the optical to the wireless and back to the optical domains. The transmitter and receiver are evaluated through Gaussian minimum shift-keying modulation accuracy metrics. Deployment of the transceiver in radio-over-fiber architectures is also discussed.

Resonant Tunneling Diode Oscillators for Optical Communications

The ability to use resonant tunneling diodes (RTDs) as both transmitters and receivers is an emerging topic, especially with regards to wireless communications. Successful data transmission has been achieved using electronic RTDs with carrier frequencies exceeding 0.3 THz. Specific optical-based RTDs, which act as photodetectors, have been developed by adjusting the device structure to include a light absorption layer and small optical windows on top of the device to allow direct optical access. This also allows the optical signal to directly modulate the RTD oscillation. Both types of RTD oscillators will allow for seamless integration of high frequency radio and optical fiber networks.

Frequency Selectivity in Directly Modulated Distributed Feedback Laser Transmission Operation Using an Impedance Match Tuning Network

A demonstration of the effect of tuning components on a directly modulated distributed feedback laser (DFB) high-frequency performance is shown in this paper. A network based on three inductors and a microstrip line is used to impedance match the parasitic reactance of a laser diode within a tuning bandwidth. The matching and transmission performance of the laser under these conditions is compared with a radio frequency network simulation that include the intrinsic model of the DFB laser with its internal parasitic reactance, and the added external microstrip components.

An Optical to Wireless Data Link Using Radio Frequency Backscatter

The changes in the impedance of an antenna-coupled photo-detector under optical illumination are used to encode data on a backscattered wireless signal similarly to the standard techniques used for radio frequency identification and tagging. The effect is strong enough to allow retrieval of the information without requiring a dc supply at the optical to wireless interface.