Experimental performance of a fully tunable complex-coefficient optical FIR filter using wavelength conversion and...

Area of Science:

• Photonics and Optical Engineering
• Nonlinear Optics
• Signal Processing

Background:

• Finite-Impulse-Response (FIR) filters are crucial in signal processing.
• All-optical implementation of complex-coefficient FIR filters is challenging.
• Tunability and reconfiguration are key requirements for advanced optical signal processing.

Purpose of the Study:

• To experimentally characterize a continuously tunable all-optical complex-coefficient FIR filter.
• To demonstrate the reconfiguration and tuning capabilities of the proposed FIR filter.
• To validate the filter's performance against theoretical predictions.

Main Methods:

• Exploiting nonlinear signal processing techniques, including multiplexing and multicasting.
• Utilizing conversion-dispersion-based optical delays for precise tap delays.
• Realizing optical FIR filters of varying lengths (3 and 4 taps) with adjustable tap amplitudes and phases.

Main Results:

• Successful experimental realization of tunable optical FIR filters with complex coefficients.
• Demonstrated control over tap amplitudes (0 to -9 dB) and phases (0 to 2π).
• Achieved close agreement between measured and theoretical frequency responses.

Conclusions:

• The developed all-optical FIR filter offers continuous tunability and reconfiguration.
• Nonlinear signal processing and optical delays provide an effective method for implementing complex-coefficient FIR filters.
• The experimental results validate the proposed approach for advanced optical signal processing applications.