Cascaded Random Raman Fiber Laser With Low RIN and Wide Wavelength Tunability

Abstract

Cascaded random Raman fiber lasers (CRRFLs) have been used as a new platform for designing high power and wavelength-agile laser sources. Recently, CRRFL pumped by ytterbium-doped random fiber laser (YRFL) has shown both high power output and low relative intensity noise (RIN). Here, by using a wavelength- and bandwidth-tunable point reflector in YRFL, we experimentally investigate the impacts of YRFL on the spectral and RIN properties of the CRRFL. We verify that the bandwidth of the point reflector in YRFL determines the bandwidth and temporal stability of YRFL. It is found that with an increase in the bandwidth of the point reflector in YRFL from 0.2nm to 1.4nm, CRRFL with higher spectral purity and lower RIN can be achieved due to better temporal stability of YRFL pump. By broadening the point reflector’s bandwidth to 1.4nm, the lasing power, spectral purity, and RIN of the 4th-order random lasing at 1349nm can reach 3.03W, 96.34%, and −115.19 dB/Hz, respectively. For comparison, the spectral purity and RIN of the 4th-order random lasing with the point reflector’s bandwidth of 0.2 nm are only 91.20% and −107.99dB/Hz, respectively. Also, we realize a wavelength widely tunable CRRFL pumped by a wavelength-tunable YRFL. This work provides a new platform for the development of ideal distributed Raman amplification pump sources based on CRRFLs with both good temporal stability and wide wavelength tunability, which is of great importance in applications of optical fiber communication and distributed sensing.

Spectral Manipulations of Random Fiber Lasers: Principles, Characteristics, and Applications

“…[105] Especially for cascaded RRFLs with broadband point reflectors and Rayleigh backscattering, the lasing wavelengths can be continuously tuned in a wide range by directly varying the pump wavelengths and pump power with no need for pairs of mirrors in the conventional fiber lasers. [37,99,[106][107][108][109] With a tunable ytterbiumdoped fiber laser pump source and a broadband reflector, the cascaded Raman random fiber lasing with a wavelength tuning range of 1070-1370 nm can be stimulated in the passive fiber. [109] Then, by further utilizing the Raman fiber, in which the zero-dispersion wavelength is >2 μm, to provide SRS gain and Rayleigh backscattering for the cascaded RRFL (as shown in Figure 6a), the Raman shifting >1.3 μm has been realized.…”

“…Reproduced under the terms of the Creative Commons CC BY license. [ 108 ] Copyright 2022, The Authors. b) Output spectra at different radiation powers of the backward‐pumped half‐open structure EYRFL.…”

“…Based on the amplified YRFL pump, a fourth‐order cascaded RRFL was demonstrated with a tunable operating wavelength. [ 108 ] The results indicate that the broadband YRFL pump is beneficial in enhancing the temporal stability and spectral purity of the RRFL. Another approach to realize RRFL pumping is to form a common structure for ytterbium/Raman RFL.…”

Review of Random Fiber Lasers for Optical Fiber Sensors

“…Since RFL was proposed, many researchers have explored the physical mechanism, output characteristics, and implementation methods of RFL. RFL has been well applied in fields such as supercontinuum spectroscopy [17][18][19][20], speckle free imaging [21][22][23][24][25][26], fiber communication [27][28][29][30][31][32][33][34][35][36], and fiber sensing [37][38][39][40][41][42][43][44][45][46][47][48][49][50]. Especially in the field of fiber optic sensing, RFL exhibits significant advantages in fiber optic sensing systems due to its simple structure, narrow linewidth, and low noise.…”

Effect of Linewidth on the Relative Intensity Noise in Random Distributed Feedback Raman Fiber Lasers

“…Some of the most relevant studies of RIN transfer in RDFLs [ 11 , 12 ] showed the influence of pump power and fiber characteristics on the frequency-dependent RIN transfer function and shed some light about the differences between RIN transfer in mode-dominated ultra-long lasing and random distributed feedback regimes. In addition, the RIN transfer and noise intensity level are becoming relevant for high-power multiple-order Raman distributed feedback lasers using short fibers [ 13 , 14 , 15 , 16 ]. Furthermore, some of this previous work [ 17 ] allowed us to theoretically predict that, in some particular configurations, the maximum RIN transfer in RDFLs, which typically happens at low modulation frequencies, could be dampened, leading to an anomalous RIN transfer profile in which pump intensity noise is transferred efficiently only to a mid-frequency band, which could help to reduce noise impairments in telecommunications and sensing.…”