Model and Methodology to Characterize Phosphor-Based White LED Visible Light Communication Links.

LED lighting has become the standard solution for illumination purposes thanks to its energy efficiency. Nowadays, there is growing interest in the use of LEDs for data transmission to develop future-generation communication systems. The low cost and widespread deployment of phosphor-based white LEDs make them the best candidate for visible light communications (VLC), although they have a limited modulation bandwidth.

Real-time 20.37 Gb/s optical OFDM receiver for PON IM/DD systems.

This paper presents the hardware architecture of an OFDM receiver suitable for optical communications. The receiver has been implemented in an FPGA device and used to demonstrate experimentally an optical OFDM transmission in a passive optical link with a directly modulated DFB laser and DAC/ADC at 5 GS/s. A bit rate of 20.

Bimodal grating coupler design on SOI technology for mode division multiplexing at 1550 nm.

In this paper, we evaluate by means of simulation and experimentally the simultaneous coupling of the LP-LP fiber modes and the TE-TE nanophotonic SOI waveguide modes using a grating coupler for a two-mode fiber at 1550 nm. Both the grating width (ranging from 10 µm to 15 µm) and the grating vertical profile have been considered in the design procedure. The optimum design (14 µm width and 609 nm grating period) has been selected in terms of coupling efficiency (both LP-TE and LP-TE), compactness and tolerance to lateral misalignments between fiber and coupler.

Design of asymmetrical directional couplers on ridge and strip SOI technology with high-dimensional variation tolerance.

The supermode analysis of asymmetrical directional couplers (ADC) based on SOI technology for strip and ridge structures at 1550 nm is herein reported, targeting to reduce ADC device fabrication requirements. The reported analysis based on supermodes permits us to assess the sensitivity of the ADC coupling efficiency by calculating the index difference between even and odd supermodes. Optimum designs have been found for 100 and 400 nm gaps, respectively, capable of converting and (de) multiplexing both TE and TE modes taking into account the width, gap, height, and slab thickness variations produced with respect to the nominal design.

Dimensional variation tolerant mode converter/multiplexer fabricated in SOI technology for two-mode transmission at 1550 nm.

The use of an integrated asymmetrical directional coupler for two-mode transmission at 1550 nm is analyzed. The design is based on silicon-on-insulator (SOI) technology and permits mode conversion and mode multiplexing/demultiplexing. In the nominal design, mode conversion and mode (de)multiplexing are achieved with 97% efficiency and a 23.

Evaluation of optical ZP-OFDM transmission performance in multimode fiber links.

In this paper, the performance of Zero Padding Orthogonal Frequency Division Multiplexing (ZP-OFDM) on intensity modulation-direct detection (IM-DD) multimode fiber (MMF) links is assessed by means of numerical simulations. The performance of ZP-OFDM is compared to classical Cyclic Prefixed form of OFDM (CP-OFDM) which is known to offer a limited performance in terms of symbol recovery in subcarriers suffering severe fading. Simulations results show that ZP-OFDM is able to reach 29 Gbps in 99.

Ten gigabits per second 16-level quadrature amplitude modulated millimeter-wave carrier generation using dual-drive Mach-Zehnder modulators incorporated photonic-vector modulator.

A novel photonic-vector modulator architecture for the generation of 16 quadrature amplitude modulation (16 QAM) millimeter-wave carriers using dual-drive Mach-Zehnder modulators is proposed. Experimental generation of 5 Gbits/s 4 amplitude shift-keying (4 ASK) and 10 Gbits/s 16 QAM modulated 42 GHz carriers is reported. The multilevel modulated millimeter-wave signals are demodulated using an electrical receiver and its error-vector magnitude (EVM) estimated from the measurements, obtaining EVMs of -21.

Generation of pure electrical quadrature amplitude modulation with photonic vector modulator.

A photonic vector modulator architecture for generating pure quadrature amplitude modulation (QAM) signals is presented. An electrical quadrature-modulated signal at microwave-millimeter-wave frequencies is generated from its corresponding baseband in-phase (I) and quadrature (Q) components. In the proposed scheme, no electrical devices apart from the electrical tone oscillator are needed in the generation process.

All-optical WDM multi-tap microwave filter with flat bandpass.

An incoherent photonic microwave filter implementing multiple positive and negative coefficients based on two sets of optical carriers and dispersive media is proposed and demonstrated. Positive and negative coefficients are obtained thanks to the pi phase inversion in a single electro-optic Mach-Zehnder modulator as well as the modulator Vpi dependence with wavelength. To show the feasibility of this technique to implement practical filter transfer functions, the Parks-McClellan algorithm has been used to design a 5-tap flat bandpass filter.