A dual-band multiwavelength erbium-doped fiber laser source

A multiwavelength erbium-doped fiber ring laser is proposed, which is based on two Mach-Zehnder interferometers in a cascade configuration. One of the interferometers acts as a wavelength filter, and the other, exhibiting a relatively small optical path difference, determines the number of lasing wavelengths. By the use of an optical switch, the operating wavelengths can be shifted between two wavelength bands, centered at 1555 and 1565 nm. A stable simultaneous ten-wavelength lasing operation with amplitude fluctuations < 5 dB, wavelength spacing ≈ 0.5 nm, and signal-to-noise ratio > 25 dB over the whole operating wavelength region has been obtained.