Tunable Microwave Photonic Bandpass Filter Research Articles

Tunable kilohertz microwave photonic bandpass filter based on backscattering in a microresonator.

A tunable microwave photonic bandpass filter (MPBPF) with a kilohertz bandwidth based on the backscattering mode of a silica microsphere resonator is proposed and experimentally demonstrated. In this work, an ultrahigh-quality-factor microsphere resonator is used to generate a radio frequency bandpass response with a bandwidth of 600 kHz. Meanwhile, scattering-induced coupling between the clockwise mode and the counterclockwise mode is introduced to reduce the number of resonance modes, and a single backscattering mode which has a high extinction ratio is obtained. Therefore, an MPBPF with a tuning range of 40 GHz and a rejection ratio of 16.9 dB is realized. This MPBPF possesses advantages such as ultranarrow bandwidth, large tuning range, and compactness, and shows great potential for microwave photonic applications.

High-Selectivity On-Chip Optical Bandpass Filter With Sub-100-MHz Flat-Top and Under-2 Shape Factor

We demonstrate a fully tunable microwave photonic bandpass filter fabricated with Si3N4/SiO2 waveguides on a chip. The filter is based on coupled resonator optical waveguide architecture comprising a chain of eight coupled ring resonators, each with an optical roundtrip length of 21 cm (free spectral range of 1.4 GHz), with an adjustable resonance frequency, and with adjustable power coupling. The passband shows a 3-dB bandwidth of 72 MHz with at least 51-dB out-of-band rejection and features simultaneously a flat-top, a shape factor of 1.9, and a group delay variation smaller than 2 ns.

Optically Tunable Frequency-Multiplying Optoelectronic Oscillator

An optically tunable frequency-multiplying optoelectronic oscillator (OEO) incorporating a tunable microwave photonic bandpass filter is proposed and experimentally demonstrated. The microwave photonic filter is implemented employing a phase-shifted fiber Bragg grating, a polarization modulator, and a phase modulator. The frequency tuning is realized by changing the wavelength of the light wave to the OEO loop. The frequency-doubling and frequency-quadrupling operations with large frequency tunability are experimentally demonstrated. The phase noise performance of the generated microwave signals is also investigated.

Microwave photonic bandpass filter based on spectrumslicing and phase modulator

A tunable microwave photonic bandpass filter with high mainlobe-to-sidelobe ratio (MSR) based on a phase modulator and a dispersive device is proposed. The multi-tap characteristics of the filter are realized by slicing a broadband source using a Mach-Zehnder interferometer (MZI) which results in a high MSR of 25 dB. The tunability of the filter is realized by an optical variable delay line (OVDL) in one arm of the MZI, which changes the wavelength spacing of the sliced broadband source and results in a tunable free spectrum range (FSR) of the filter. The central frequency of the bandpass filter is tunable from 10.7 GHz to 27 GHz by changing the wavelength spacing from 0.145 nm to 0.054 nm.

Tunable microwave photonic bandpass filter with high-resolution, coherence-free operation

Two new structures that can realise both tunable and high-resolution filter operation simultaneously, together with low-noise, are presented. Experimental results demonstrate a wide tuning range for high-resolution low-noise bandpass filters with a Q value of 200.

Microwave photonic bandpass filter using a multi‐wavelength laser with a bell‐shaped power profile

AbstractA low cost sidelobe suppressed tunable microwave photonic bandpass filter is proposed and experimentally demonstrated. The filter is based on a multi‐wavelength ring laser and a segment of single mode fiber as a dispersive element. Through adjustment of the power profile of the multi‐wavelength laser to a bell shape, a filter frequency response without sidelobes is achieved. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1329–1332, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24316

Novel Continuously Tunable Microwave Photonic Bandpass Filter

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A new technique for tuning the passband frequency of a microwave photonic bandpass filter is presented. It is based on controlling the polarization state of the signal in an amplified recirculating delay line loop with a polarizer at the output. A fixed wavelength laser can be used as an optical source. The filter has a sharp passband, which can be tuned continuously while maintaining the same passband width. Experimental results demonstrate continuous tuning capability of the high-resolution bandpass filter. </para>