Estimate grating behavior for sensing and filtering tasks. Test wavelength, period, order, strain, temperature inputs. View formulas, graphs, exports, examples, and guidance easily here.
A Bragg grating is a periodic index structure that reflects a narrow wavelength band while transmitting nearby wavelengths. Engineers use these devices in fiber sensing, filtering, wavelength locking, and structural monitoring. This calculator handles the core Bragg relation and also extends the analysis with strain and temperature effects.
The form can solve for Bragg wavelength, grating period, or effective index. It also estimates frequency, bandwidth, and reflectivity from length and index modulation. The graph plots a simple response shape around the base wavelength and the shifted wavelength so you can compare operating conditions quickly.
Use strain in microstrain, then convert to strain by multiplying by 10-6. Use α and ξ in reciprocal degrees Celsius. Length is entered in millimeters and wavelength values are shown in nanometers.
| Case | n_eff | Λ (nm) | m | Strain (µε) | ΔT (°C) | Base λ_B (nm) | Shifted λ_B (nm) |
|---|---|---|---|---|---|---|---|
| Structural sensing | 1.45 | 534.48 | 1 | 500 | 5 | 1550.00 | 1550.68 |
| Optical filter | 1.46 | 531.00 | 1 | 0 | 0 | 1550.52 | 1550.52 |
| Higher order design | 1.44 | 1086.81 | 2 | 200 | 2 | 1565.01 | 1565.28 |
It evaluates the relationship between effective index, grating period, order, and reflected wavelength. This version also estimates shift effects from strain and temperature, plus simple reflectivity behavior.
Effective index controls the optical path inside the guided mode. A small change in n_eff directly changes the Bragg wavelength, so accurate mode data improves design accuracy.
Order describes which harmonic of the periodic structure satisfies the Bragg condition. First order is common, but higher orders can be used for special designs and fabrication goals.
Strain changes both grating spacing and optical properties. Temperature changes material expansion and refractive behavior. Together they shift the reflected wavelength from its original design value.
Real grating spectra depend on apodization, chirp, loss, fabrication tolerances, and boundary effects. The calculator uses a compact coupling estimate, which is useful for planning but not full device simulation.
Use nanometers for wavelength and period, millimeters for length, microstrain for strain, and reciprocal degrees Celsius for thermal coefficients. The report keeps the same units for clarity.
Yes. It is useful for fiber sensing, wavelength-selective filtering, and quick engineering checks. It helps compare static designs and operating shifts before detailed modeling.
Most issues come from mixed units, incorrect order selection, negative or zero physical inputs, or thermal coefficients copied from a different material system. Check every input before final design decisions.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.