Tunable all-optical negative multitap microwave filters based on uniform fiber Bragg gratings

We present a novel and simple technique for obtaining transversal filters with negative coefficients by using uniform fiber Bragg gratings. We demonstrate a wide tuning range, good performance, low cost, and easy implementation of multitap filters in an all-optical passive configuration in which negative taps are obtained by use of the transmission of a broadband source through uniform Bragg gratings.     

Arrayed waveguide Sagnac interferometer

We present a novel device, an arrayed waveguide Sagnac interferometer, that combines the flexibility of arrayed waveguides and the wide application range of fiber or integrated optics Sagnac loops. We form the device by closing an array of wavelength-selective light paths provided by two arrayed waveguides with a single 2 x 2 coupler in a Sagnac configuration. The equations that describe the device's operation in general conditions are derived. A preliminary experimental demonstration is provided of a fiber prototype in passive operation that shows good agreement with the expected theoretical performance. Potential applications of the device in nonlinear operation are outlined and discussed.     

Performance parameters and applications of a modified amplified recirculating delay line

A theoretical study of the proposed modified recirculating delay line (MARDL) is described using a time-domain analysis to derive the optical transfer function. Those cases that present novel and interesting features in the transfer function are identified. Design flexibility and tuning capabiliv, dependent on the different parameters that define the structure, are analyzed. Possible applications of the MARDL as a photonic high-selectivity filter and /or tunable notch filters are discussed.     

Theory of integrated ring resonators using electro-optical couplers

In this paper we focus on integrated resonators that employ electro-optical couplers and phase shifters and, thus, are capable of providing high-speed channel tunability and coupling constant variation. We find that, although a conventional operation is always attainable, integrated resonators can, in some cases, present an anomalous behavior compared to that of their fiber-based equivalents. These can have potential applications.     

An analysis on the effect of the equalizer parameters in a direct-modulation optical communication system employing an all-pass filter to combat chirp and dispersion

We consider the effect of the equalizer parameters in the performance of a direct modulated high-bit-rate communication system where the degrading combination of fibre dispersion and source chip is compensated using an all-pass optical filter.     

Tunable radio-frequency photonic filter based on an actively mode-locked fiber laser

We propose the use of an actively mode-locked fiber laser as a multitap optical source for a microwave photonic filter. The fiber laser provides multiple optical taps with an optical frequency separation equal to the external driving radio-frequency signal of the laser that governs its repetition rate. All the optical taps show equal polarization and an overall Gaussian apodization, which reduces the sidelobes. We demonstrate continuous tunability of the filter by changing the external driving radio-frequency signal of the laser, which shows good fine tunability in the operating range of the laser from 5 to 10 GHz.