C-band 41-wavelength-switchable single-longitudinal-mode fiber laser with sub-kHz linewidth and high stability using a wide-band chirped Moiré fiber Bragg grating

Abstract

A high-performance wavelength-switchable single-longitudinal-mode (SLM) fiber laser with ultra-narrow linewidth and high stability in C-band was proposed and demonstrated, mainly benefiting from the use of a wide-band chirped Moiré fiber Bragg grating (WB-CM-FBG) with 41 ultra-narrow channels. By combining the WB-CM-FBG with a manual tunable bandpass filter and using a subring cavity with a length of only 34 cm to efficiently stabilize the SLM lasing, we achieved switchable lasing operation among 41 wavelengths, with a switching-step of ~0.96 nm from 1526.592 nm to 1565.126 nm, covering the whole C-band, and obtained sub-kHz linewidth at every lasing wavelength. The high stability was validated by the measured slight fluctuations of lasing wavelength and optical power of <0.004 nm and <0.113 dB, respectively, in 1.5 h. To the best of authors’ knowledge, this is the state-of-the-art CM-FBG-based fiber laser reported with the greatest number of switchable-wavelengths covering C-band, and, what’s more, each switchable lasing wavelength was with sub-kHz linewidth. The performance of the proposed fiber laser can be improved further with good temperature compensation and vibration isolation packaging for practical applications.

Six-Wavelength-Switchable SLM Thulium-Doped Fiber Laser Enabled by Sampled FBGs and 3 × 3 Coupler Based Dual-Ring Compound Cavity Filter

“…The multi-channel optical filter can be one of the following: a photonic crystal fiber based Mach-Zehnder interferometer [11], a superimposed FBG [12,13], a wideband chirped Moiré FBG filter [14,15], a sample fibered Bragg grating (SFBG) or a polarization-maintaining (PM) SFBG [16,17], a Sagnac interferometer [18], a few-mode fiber with core-offset structure [19], etc. The wavelength switching mechanism can be one of the following: tunable-filter scanning [20], polarization-dependent loss (PDL) [21], polarization controlling [17], or nonlinear polarization rotation (NPR) [16,22], etc. To further enable SLM lasing for the wavelength-switchable laser, it is critical to find effective mode-selection mechanisms against the resulting small FSR due to the elongated laser cavity length.…”

Selectivity analysis of femtosecond laser polarizer by three-layer grating

“…Compared with ordinary light source, laser has the advantages of good mono-chromaticity, high brightness and good directivity, and the combination of diffraction grating and laser light source suitable for integration is widely used in many modern optical systems [1,2], such as switches [3][4][5][6], sensors [7][8][9][10], solar cells [11][12][13][14] spectrometer [15,16], polarizer [17,18], laser [19][20][21][22], beam splitter [23], wavelength multiplexers [24], and so on. The surface-relief grating is fabricated by a photolithography process [25].…”