Laser Linewidth and Bandwidth Calculator
Convert a laser's wavelength linewidth to frequency bandwidth.
A laser's spectral linewidth in wavelength corresponds to a frequency bandwidth.
How the Math Works
The Laser Linewidth and Bandwidth Calculator uses the formula Δν = c·Δλ ÷ λ² to convert a laser's wavelength linewidth (Δλ) into its frequency bandwidth (Δν). Here, c represents the speed of light (approximately 3×10⁸ m/s), λ is the laser's central wavelength, and Δλ is the small variation in wavelength. This relationship stems from the inverse connection between frequency and wavelength (ν = c/λ), where a tiny change in wavelength translates to a proportional change in frequency. The formula approximates the derivative of frequency with respect to wavelength, ensuring accuracy when Δλ is much smaller than λ.
Practical Applications
To use this calculator, input the laser's central wavelength and its linewidth in compatible units (e.g., nanometers). The tool automatically applies the formula, multiplying the speed of light by the wavelength linewidth and dividing by the square of the central wavelength. This conversion is critical in fields like optics and telecommunications, where precise frequency bandwidth determines a laser's performance in applications such as fiber-optic data transmission or spectroscopy. For instance, a laser with a narrower linewidth (smaller Δλ) yields a tighter frequency bandwidth (Δν), enhancing signal quality and resolution in precision instruments.
Day-to-Day Use
While lasers may seem high-tech, their precise properties impact everyday technology. This calculator helps engineers design lasers for devices like barcode scanners, CD/DVD players, and medical equipment, where tight frequency control ensures reliability and safety. In telecommunications, accurate bandwidth calculations optimize internet speeds by minimizing signal distortion in fiber-optic cables. Even in consumer electronics, such as laser pointers or printers, understanding these parameters ensures consistent performance, making the math behind this tool a quiet but vital part of modern life.
Worked example
1064 nm with 1 pm linewidth → about 265 GHz.
FAQ
Why does linewidth matter?
Narrow linewidth gives long coherence length, vital for interferometry and comms.