Demo File: Gires–Tournois Interferometer (GTI)

Demo File: Gires–Tournois Interferometer (GTI)

Demo File: Gires–Tournois Interferometer (GTI)
Source: ResearchGate

Gires–Tournois Interferometer: A Tool for Dispersion Compensation

The Gires–Tournois interferometer (GTI) is a device commonly used for dispersion compensation in mode-locked lasers. It consists of a Bragg mirror, a thicker layer, and a thin top layer, operating similarly to a Fabry–Pérot interferometer in reflection. The interference effect from the top mirror leads to a periodic variation of the phase change, resulting in chromatic dispersion.

Structure of a Gires–Tournois Interferometer

The GTI structure typically includes a Bragg mirror with a specific Bragg wavelength, a certain number of layer pairs, and a thick SiO2 layer. The interference layers are usually composed of TiO2 and SiO2, with specific thicknesses at the Bragg wavelength. The superstrate is commonly air, while the substrate is often BK7.

Reflectivity Profile and Group Delay

The reflectivity profile of a GTI shows high reflectivity across a range of wavelengths, with periodic variations due to interference effects. The group delay in reflection is highest at resonances, impacting the overall dispersion characteristics of the device.

Group Delay Dispersion and Intensity Patterns

The group delay dispersion curve illustrates how the dispersion changes with wavelength, affecting the pulse broadening or compression. Intensity patterns versus wavelength demonstrate the depth within the mirror structure where specific intensity levels are observed.

Simulation of Ultrashort Pulse Reflection

Although not directly designed for this purpose, it is possible to simulate the reflection of ultrashort pulses using appropriate script code. By defining complex amplitudes and electric fields, one can analyze the behavior of ultrashort pulses within the GTI structure.

Time-Resolved Field Intensity Distribution

The time-resolved field intensity distribution provides insights into how incoming pulses interact with the GTI structure, leading to multiple reflected pulses at different time intervals. Understanding this distribution is crucial for optimizing the performance of the GTI for specific applications.

In conclusion, the Gires–Tournois interferometer is a valuable tool for dispersion compensation in lasers, offering control over chromatic dispersion and pulse shaping. By studying its structural and optical characteristics, researchers and engineers can enhance the performance of mode-locked lasers and other optical systems.

Demo File: Gires--Tournois Interferometer (GTI)
Source: ResearchGate
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