Related Experiment Video
Updated: Jun 18, 2025
00:07
A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
8.4K
Polarization-insensitive multimode interference coupler on an x-cut thin-film lithium niobate platform
Optics Letters
|August 2, 2024
Summary
Researchers developed a novel polarization-insensitive multimode interference (MMI) coupler for thin-film lithium niobate photonics. This breakthrough enables crucial polarization management in optical communication systems.
Area of Science:
- Integrated photonics
- Materials science
- Optical communications
Background:
- Thin-film lithium niobate (TFLN) is a key platform for integrated photonics.
- Existing TFLN technology lacks polarization-insensitive multimode interference (MMI) couplers.
- MMI couplers are essential for polarization management, division multiplexing, and insensitive modulation in optical communications.
Purpose of the Study:
- To design and demonstrate a novel polarization-insensitive MMI coupler on TFLN.
- To address the limitations of current TFLN-based polarization control components.
- To enable advanced polarization-dependent functionalities in photonic integrated circuits.
Main Methods:
- Utilizing anisotropic x-cut TFLN.
- Rotating the MMI structure at specific angles.
- Compensating for polarization-dependent beat length differences.
Main Results:
- Experimental achievement of a polarization-insensitive 1x2 MMI coupler.
- Measured transmittances ranging from -2.5 to -4 dB for both output ports.
- Operation demonstrated across the 1520-1580 nm wavelength range for both polarization modes.
Conclusions:
- The novel MMI coupler design successfully achieves polarization insensitivity on TFLN.
- This development is critical for advancing polarization-related optical communication applications.
- The demonstrated device offers a viable solution for polarization management in TFLN photonic systems.
Related Concept Videos
01:31Dielectric Polarization in a Capacitor
4.6K
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...
4.6K
01:28Induced Electric Dipoles
4.2K
A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
4.2K
01:27Biasing of Metal-Semiconductor Junctions
235
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
235
01:16Biasing of P-N Junction
485
The operation of a p-n junction diode involves various biasing conditions, including forward bias, reverse bias, and equilibrium.
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
485