Linewidth-narrowing and intensity noise reduction of the 2nd order Stokes component of a low threshold Brillouin laser made of Ge_10As_22Se_68 chalcogenide fiber

Abstract

A compact second-order Stokes Brillouin fiber laser made of microstructured chalcogenide fiber is reported for the first time. This laser required very low pump power for Stokes conversion: 6 mW for first order lasing and only 30 mW for second order lasing with nonresonant pumping. We also show linewidth-narrowing as well as intensity noise reduction for both the 1 st and 2 nd order Stokes component when compared to that of the pump source.

Original designs of chalcogenide microstuctured optical fibers

“…Only the Brillouin thresholds are significantly different. Indeed, the Brillouin threshold reach 85 mW in a 4·9 m-long SIF [35], while a threshold of only 6 mW were observed in only 3-m long MOF [36] (In that study the fiber design was close to the design illustrated in Figure 3(c)). The single-frequency Brillouin laser made with this fiber showed a promising frequency noise reduction of nearly 6 dB, as compared to the noise of the pump laser.…”

“…composition-dependent, with values of 8·2 GHz in a sulfur fiber [28] and 7·95 GHz in As-Se fibers (SIF or MOF) [35,36].…”

“…Stimulated Brillouin scattering (SBS) in optical fibers are important nonlinear interactions that can be exploited to obtain wavelength conversion and highly coherent lasers, specifically in chalcogenide fibers where the Brillouin gain (gB) can reach more than 120 times the gain measured in a silica fiber. Thus, gB is as high as 5·5 10 −9 m W −1 and 6·0 10 −9 m W −1 in chalcogenide MOF and step index fibers (SIFs), respectively [35,36]. Only the Brillouin thresholds are significantly different.…”

Chalcogenide Brillouin lasers

“…In both fiber 15,16 and waveguide 18 experiments, the configuration of the laser cavity imposed restrictions on the amount of power that could be coupled out of the cavity for detection. The output coupler with a larger fraction would introduce an extra loss per round trip and lead to an increase in the lasing threshold.…”

Narrow linewidth Brillouin laser based on chalcogenide photonic chip

“…One possible way to build such a laser is to exploit the intrinsically narrow linewidth and tunability of stimulated Brillouin scattering (SBS). Recent studies have demonstrated that Brillouin lasers (BLs) can have orders of magnitude higher coherence than their pump sources [4][5][6][7]. The phase noise of the pump is transferred to the Stokes wave, but with significantly reduced magnitude due to the combined action of acoustic damping and cavity feedback [4].…”