An atomic optical filter working at 1.5 μm based on internal frequency stabilized laser pumping.

Area of Science:

• Atomic physics
• Optical engineering
• Photonics

Background:

• Excited state Faraday anomalous dispersion optical filters (ES-FADOF) are crucial for optical communication.
• Traditional ES-FADOFs often require complex external frequency stabilization systems.
• Improving the efficiency and compactness of these filters is an ongoing research goal.

Purpose of the Study:

• To realize a compact ES-FADOF operating at optical communication wavelengths (1.5 μm).
• To propose and implement an internal frequency stabilization scheme for enhanced performance.
• To increase the transmittance and simplify the structure of the atomic filter.

Main Methods:

• Development of an ES-FADOF utilizing an internal frequency stabilization scheme.
• Employing the working atoms within the filter as the frequency reference.
• Utilizing a specific cross-line of multiple transitions for pump laser frequency stabilization.

Main Results:

• Achieved a significantly higher pump efficiency compared to previous ES-FADOF schemes.
• Increased filter transmittance from 10% to 60% at 100 °C.
• Eliminated the need for external frequency stabilization, leading to a reduced filter volume.

Conclusions:

• The proposed internal frequency stabilization scheme enables the realization of a compact and efficient ES-FADOF.
• This simplified structure enhances the practical applicability of atomic filters in optical communication.
• The method offers a significant improvement in transmittance and operational efficiency.