Stability Comparison of Two Ring Resonator Structures for Multiwavelength Fiber Lasers Using Highly Doped Er-Fibers

Abstract

An experimental comparison of stability between two different fiber laser topologies is carried out. The lasers are based on ring resonators that include highly-doped Er-fibers. Both topologies use fiber Bragg grating reflectors in order to select the emission wavelengths. The experimental results confirms that the novel topology based on fiber optic circulators arranged in an hybrid serial-parallel configuration offers a better stability and higher optical signal to noise ratios (OSNR) than the simpler based on a parallel configuration.

Multi-Wavelength Fiber Lasers

“…However, some alternative fiber laser configurations have been shown, where these kinds of devices can be suppressed from the cavity rings by using optical circulators [7]. Theoretically, a polarization controller is also needed for conventional doped fiber that does not preserve polarization.…”

“…Theoretically, a polarization controller is also needed for conventional doped fiber that does not preserve polarization. However, some works [7] have demonstrated that this device has little influence on the multiwavelength regime. Ring fiber lasers are also known to be susceptible to power fluctuations.…”

“…A systematically effort to study these causes has been carried out. Based on previous experience these studies have been focused on optimization of some the following parameters: pump power [19], doped fiber length and ions concentration [26], output coupling ratio [7], total cavity length [26], spectral hole-burning effect [27] or the cavity losses [28]. However, polarization control seems not very important for the multimode regime [7].…”

“…These new sensing configurations offer a much improved SNR than the non-lasing ones. Initially Er-doped fiber amplifiers were utilized, being nowadays utilized Raman amplification, EDFAs and SOAs depending on the application and distance to be achieved [7]. Several approaches based on fiber lasers have been reported in order to realize long-distance and remote sensing.…”

Stability performance of short cavity Er-doped fiber lasers

“…Because of this, different doped fiber lengths were studied in order to maximize the output power for each value of launched pump power. However, the stability dependence is non-monotonic and strongly depends on the active fiber length [12][13][14].…”