title: Photo-detectors integrated with resonant tunneling diodes.
abstract: We report on photo-detectors consisting of an optical waveguide that incorporates a resonant tunneling diode (RTD). Operating at wavelengths around 1.55 μm in the optical communications C band we achieve maximum sensitivities of around 0.29 A/W which is dependent on the bias voltage. This is due to the nature of RTD nonlinear current-voltage characteristic that has a negative differential resistance (NDR) region. The resonant tunneling diode photo-detector (RTD-PD) can be operated in either non-oscillating or oscillating regimes depending on the bias voltage quiescent point. The oscillating regime is apparent when the RTD-PD is biased in the NDR region giving rise to electrical gain and microwave self-sustained oscillations Taking advantage of the RTD's NDR distinctive characteristics, we demonstrate efficient detection of gigahertz (GHz) modulated optical carriers and optical control of a RTD GHz oscillator. RTD-PD based devices can have applications in generation and optical control of GHz low-phase noise oscillators, clock recovery systems, and fiber optic enabled radio frequency communication systems.
authors.affiliation: Centro de Electrónica, Optoelectrónica e Telecomunicações (CEOT), Departamento de Física, Universidade do Algarve, Faro, Portugal. bmromeira@ualg.pt
authors.forename: Bruno
authors.initials: B
authors.lastname: Romeira
authors.forename: Luis M
authors.initials: LM
authors.lastname: Pessoa
authors.forename: Henrique M
authors.initials: HM
authors.lastname: Salgado
authors.forename: Charles N
authors.initials: CN
authors.lastname: Ironside
authors.forename: José M L
authors.initials: JM
authors.lastname: Figueiredo