Abstract
Optical modulation characteristics of resonant tunneling diode photodetectors (RTD-PD) are investigated. Intensity modulated light excites the RTD-PDs to conduct data experiments. Simple and complex data patterns are used with results showing data rates up to 80 and 200 Mbit/s, respectively. This is the first demonstration of complex modulation using resonant tunneling diodes. © 2019 The Authors. Microwave and Optical Technology Letters published by Wiley Periodicals, Inc.

Abstract
The performance of Resonant Tunnelling Diode (RTD) oscillators with an optical window is evaluated experimentally, in the transmission of advanced modulation formats using electrical and optical modulation, for the first time. Additionally, the impact of phase noise in the transmission performance is also assessed. © 2018 IEEE.

Abstract
In this paper, we investigate the optical modulation characteristics of a resonant tunnelling diode (RTD) oscillator. This preliminary work on the first RTD-PD oscillators with an optical window available from the iBROW project demonstrate that this device can effectively be used to accomplish amplitude and frequency modulation with light injection. © 2017 IEEE.

Abstract
In this paper, we further explore the concept of phase-conjugated twin waves (PCTW) for nonlinear cancellation in space-division multiplexed (SDM) systems. Previously, we demonstrated that the PCTW technique can successfully provide nonlinear cancellation in SDM systems. In this paper, we investigate the cases where two and four spatial modes are copropagating in a multimode fiber, considering three link lengths (1000, 3200, and 8000 km). Weak-and strong-coupling regimes are also evaluated. Our numerical simulation results show an average performance improvement > 10 dB after a 1000 km transmission link.

Abstract
Spatial division multiplexing (SDM) is seen as an effective technique to overcome the present limits of fiber capacity and satisfy future bandwidth requirements, by substantially increasing optical transport capacities [1-5]. Similarly to single-mode fiber based modern telecommunication systems, the nonlinear penalties will eventually become the ultimate limiting factor in SDM systems, arising from crosstalk effects in multimode core or few mode fibers, which generate intramodal and intermodal nonlinearities. Here we explore the concept of conjugated twin waves in few mode fibers based SDM optical systems, as a means to overcome these nonlinear impairments and assess the performance of SDM systems for different PCTW configurations and coupling regimes. Our numerical simulation results show that this technique is an effective means to overcome the nonlinear impairments arising in mode division multiplexed systems, improving performance by up to 10 dB, in the strong coupling regime.