High-Q microwave photonic filter with a tuned modulator

We propose the use of tuned electro-optic or electroabsorption external modulators to implement high-quality (high-Q) factor, single-bandpass photonic filters for microwave signals. Using this approach, we experimentally demonstrate a transversal finite impulse response with a Q factor of 237. This is to our knowledge the highest value ever reported for a passive finite impulse-response microwave photonic filter.     

Effects of fourth-order dispersion in very high-speed optical time-division multiplexed transmission

We present a closed-form expression for computation of the output pulse's rms time width in an optical fiber link with up to fourth-order dispersion (FOD) by use of an optical source with arbitrary linewidth and chirp parameters. We then specialize the expression to analyze the effect of FOD on the transmission of very high-speed linear optical time-division multiplexing systems. By suitable source chirping, FOD can be compensated for to an upper link-length limit above which other techniques must be employed. Finally, a design formula to estimate the maximum attainable bit rate limited by FOD as a function of the link length is also presented.     

Computer simulation of an all-optical coherent code division multiple-access network

This article presents a simulation technique for the analysis of all-optical coherent code division multiple-access asynchronous networks, Graphical results are given showing the signal evolution at different parts of the network, and the various sources of noise that degrade the overall performance are pointed out, including the influence of fiber dispersion, laser biasing, and chirp.     

Ultracompact electro-optic phase modulator based on III-V-on-silicon microdisk resonator

A novel ultracompact electro-optic phase modulator based on a single 9 μm-diameter III-V microdisk resonator heterogeneously integrated on and coupled to a nanophotonic waveguide is presented. Modulation is enabled by effective index modification through carrier injection. Proof-of-concept implementation involving binary phase shift keying modulation format is assembled. A power imbalance of ～0.6 dB between both symbols and a modulation rate up to 1.8 Gbps are demonstrated without using any special driving technique.     

Optical microwave filter based on spectral slicing by use of arrayed waveguide gratings

We have experimentally demonstrated a new optical signal processor based on the use of arrayed waveguide gratings. The structure exploits the concept of spectral slicing combined with the use of an optical dispersive medium. The approach presents increased flexibility from previous slicing-based structures in terms of tunability, reconfiguration, and apodization of the samples or coefficients of the transversal optical filter.     

Tunable and reconfigurable microwave filter by use of a Bragg-grating-based acousto-optic superlattice modulator

We present an all-optical novel configuration for implementing multitap transversal filters by use of a broadband source sliced by fiber Bragg grating arrays generated by propagating an acoustic wave along a strong uniform fiber Bragg grating. The tunability and reconfigurability of the microwave filter are demonstrated.     

Applications of Fiber Bragg Gratings to Microwave Photonics (Invited Paper)

Some of the work that has been recently carried outjointly by the Optical Communications Group of the Universidad Politécnica de Valencia and the Optical Fibre Group of the Universidad de Valancia on the applications of fiber Bragg gratings to microwave photonics is described. The paper investigates separately some applications of linearly chirped fiber Bragg gratings (LCFBGs) and uniform fiber Bragg gratings (UFBGs).     

Dual-wavelength green laser with a 4.5 THz frequency difference based on self-frequency- doubling in Nd3+ -doped aperiodically poled lithium niobate

We report a dual-wavelength continuous-wave laser at 542.4 and 546.8 nm based on an Nd(3+)-doped aperiodically poled lithium niobate crystal. Two fundamental infrared (IR) wavelengths at 1084.8 and 1093.6 nm are simultaneously oscillated and self-frequency-doubled to green. The aperiodic domain distribution patterned in the crystal allows for quasi-phase matched self-frequency-doubling of both IR fundamentals while avoiding their sum-frequency mixing.     

Transmission and group-delay characterization of coupled resonator optical waveguides apodized through the longitudinal offset technique

In this Letter, the amplitude and group delay characteristics of coupled resonator optical waveguides apodized through the longitudinal offset technique are presented. The devices have been fabricated in silicon-on-insulator technology employing deep ultraviolet lithography. The structures analyzed consisted of three racetracks resonators uniform (nonapodized) and apodized with the aforementioned technique, showing a delay of 5 ± 3 ps and 4 ± 0.5 ps over 1.6 and 1.4 nm bandwidths, respectively.