High resolution light intensity spectrum analyzer (LISA) based on Brillouin optical filter

Area of Science:

• Optoelectronics
• Nonlinear Optics
• Optical Communications

Background:

• Characterizing radio frequency (RF) modulation spectra of optical signals is crucial for high-speed optical communication systems.
• Existing methods may lack the resolution or dynamic range required for detailed analysis.

Purpose of the Study:

• To present and experimentally validate a high-resolution light intensity spectrum analyzer technique for deriving the RF modulation spectrum of optical signals.
• To assess the influence of the fiber electrostriction effect on the measurement accuracy.

Main Methods:

• Utilizing the cross-phase modulation (XPM) nonlinear effect in a dispersion-shifted fiber to generate the light intensity spectrum.
• Employing a Brillouin optical filtering method for high-resolution spectrometric analysis.
• Measuring RF spectra of pseudo-random binary sequence (PRBS) modulated optical signals at 2.5 Gb/s and 10 Gb/s.

Main Results:

• Experimental confirmation of the high-resolution light intensity spectrum analyzer technique.
• Accurate measurement of RF spectra for 2.5 Gb/s and 10 Gb/s PRBS modulated optical signals.
• Comparison with electrical domain measurements validates the technique's capabilities.
• Quantification of the fiber electrostriction effect's influence.

Conclusions:

• The presented technique offers a high-resolution method for RF modulation spectrum analysis of optical signals.
• The technique is experimentally validated and capable of analyzing signals modulated at multi-gigabit rates.
• Understanding the fiber electrostriction effect is important for precise measurements in optical systems.