Experimental cascaded operation of low-birefringence nonlinear-optical loop mirrors

Area of Science:

• Optics and Photonics
• Nonlinear Optics
• Optical Signal Processing

Background:

• All-optical logic gates are crucial for high-speed optical signal processing.
• Cascading optical logic gates is essential for advanced applications like header processing in time-division-multiplexed networks.
• Nonlinear-optical loop mirrors (NOLMs) are key components for all-optical switching.

Purpose of the Study:

• To experimentally demonstrate a low-birefringence (low-bi) nonlinear-optical loop mirror (NOLM).
• To showcase the advantages of the low-bi NOLM, including low switching energy, timing jitter tolerance, and cascadability.
• To validate the cascaded operation of two low-bi NOLMs for practical applications.

Main Methods:

• Utilizing a passively mode-locked fiber laser generating 450-fs pulses at 1.55 microm.
• Employing low-birefringence (Deltan ~ 3.0 x 10(-6)) polarization-maintaining fiber for long interaction lengths.
• Experimentally configuring and testing cascaded low-bi NOLM devices.

Main Results:

• Achieved a switching contrast ratio of 10.7:1.
• Obtained a timing window of 2.7-pulse-widths after cascaded gates.
• Demonstrated successful cascaded operation of two low-bi NOLMs.

Conclusions:

• The low-bi NOLM offers significant advantages for all-optical switching applications.
• The demonstrated cascadability is a critical step towards practical high-speed optical signal processing.
• Experimental results align with theoretical predictions, confirming the device's efficacy.