The linewidth of a laser, e.g. a single-frequency laser, is the width (typically the full width at half-maximum, FWHM) of its optical spectrum. It is the width of the power spectral density of the emitted electric field in terms of frequency, wavenumber or wavelength.
DFB lasers, known for narrow linewidths (low linewidths ), typically their linewidths are in the range of 1 MHz to 10 MHz. Some DFB lasers can achieve even narrower linewidths, like sub-MHz (685 kHz) in certain applications. The narrow linewidths are crucial for applications like optical communication, sensing, and precise measurements.
Narrow linewidth: Employing the built-in isolator enables achieving a typical linewidth of approximately 1MHz.
Typical DFB Laser Linewidth: The general range for DFB lasers is 1 MHz to 10 MHz.
A narrow linewidth (a laser with a high degree of monochromaticity,is important for achieving high-fidelity optical communication, precise measurements, and other applications where a stable and well-defined light source is needed.
Many commercially available DFB lasers are designed to operate with low linewidths and offer options like tuning and modulation capabilities.