High SBS-threshold single-mode single-frequency monolithic pulsed fiber laser in the C-band

Abstract

We report a high SBS-threshold, single-frequency, single-mode, polarization maintaining (PM) monolithic pulsed fiber laser source in master oscillator and power amplifier (MOPA) configuration that can operate over the C-band. In order to achieve a narrow transform-limited linewidth for pulses longer than 100 ns, we use a single-frequency Q-switched fiber laser seed, which itself can be seamlessly tuned up to 1.24 micros. The Q-switched pulses are amplified in the power amplifier stage of MOPA using a high SBS threshold single-mode PM large core highly Er/Yb co-doped phosphate glass fiber (LC-EYPhF). This seed and amplifier combination represents the first monolithic, all-fiber implementation of a single-frequency pulsed laser with the highest pulse energy of 54 microJ and peak power of 332 W for 153-ns pulses at 1538 nm.

Highly Doped Phosphate Glass Fibers for Compact Lasers and Amplifiers: A Review

“…In 2009 Shi et al [21] proposed the use of a single-mode PM large core highly Er/Yb co-doped phosphate fiber for engineering the final power amplifier stage of a monolithic all-fiber pulsed MOPA laser operating in the C band. Single-mode operation was achieved in such a large core (15 µm) thanks to the accurate control of the refractive indices of the core and the cladding obtainable in phosphate glasses (core NA = 0.053).…”

“…In addition, the characteristic temperatures difference between phosphates and silica, as well as the sharp difference in physical properties between standard commercial silica based fibers and phosphate ones, has slowed down the exploitation of these fibers due to the more challenging integration in all-fiber devices. Nonetheless, splicing of phosphate fibers to silica based fibers and fiber components (for example couplers and Fiber Bragg Gratings) is nowadays commonly employed, with relatively low loss (0.2 dB per joint) and high strength [19][20][21].…”

Theoretical analysis of a method for extracting the phase of a phase-amplitude modulated signal generated by a direct-modulated optical injection-locked semiconductor laser

“…7,8 However, these external modulators exhibit several limitations, including large-form factors and high cost, and are typically difficult to integrate with other photonic devices. [9][10][11] To overcome these limitations, optical injection-locked (OIL) lasers have been proposed and found effective for generating signals with PM simply by changing the injectionlocking parameters, specifically, the detuning frequency between the master and free-running slave lasers and the injection ratio between the powers of the master and slave lasers. [12][13][14] We recently reported the theoretical analysis of the PM of an OIL laser based on the direct modulation (DM) of a slave laser, the results of which demonstrated the successful enhancement of the PM range up to 360 deg using a cascaded connection of injection-locked laser stages.…”

Stimulated Brillouin Scattering Suppression With a Chirped Laser Seed: Comparison of Dynamical Model to Experimental Data

“…Since the SBS threshold scales as 1/L eff it is common practice to limit the length of the fiber to achieve large threshold values [3]. Using thermal/stress gradients changes the Brillouin frequency along the length of the fiber decreasing L eff , but becomes impractical after a few times threshold enhancement [4].…”