Highly nonlinear photonic crystal fiber with ultrahigh birefringence using a nano-scale slot core

• A new type of slot photonic crystal fiber is proposed.
• Ultrahigh nonlinear coefficient up to 3.5739 × 104 W−1 km−1 can be achieved for the quasi-TM mode.
• The modal birefringence at 1.55 μm is up to 0.5015.
• The proposed PCF is suitable for all-optical signal processing.

A new type of highly nonlinear birefringent photonic crystal fiber (HNL_PCF) with nano-scale slot core is proposed and numerically simulated. Benefit from the slot effect induced sub-wavelength mode confinement, ultrahigh nonlinear coefficient up to 3.5739 × 104 W−1 km−1 can be achieved for the quasi-TM mode at the wavelength of 1.55 μm. Additionally, the modal birefringence can go up to 0.5015 due to the asymmetry of the fiber structure. Leveraging the extraordinary features, the proposed HNL-PCF offers large potential in miniature fiber devices for all-optical signal processing.