Experimental investigation of optimal conventional CW pump laser architectures for low-intensity noise supercontinuum generation in standard telecom fibers

We report an experimental study of supercontinuum (SC) generation in standard telecom fiber driven by continuous-wave cascaded random Raman fiber-laser (CRRFL) pumps, with emphasis on minimizing intrinsic intensity noise. We tested three Ytterbium (Yb) fiber pump architectures: a bidirectional fiber Bragg grating (FBG) linear-cavity laser and two master-oscillator power amplifier (MOPA) systems seeded by either an FBG laser or a unidirectional ring-cavity laser. In all configurations, approximately 75 W of CW power at 1064 nm was launched into 2 km of SMF-28e, producing supercontinuum output powers up to ⁓34 W with spectral coverage extending from 1000 to 1700 nm and power spectral densities (PSD)exceeding 50 mW/nm. The wavelength-resolved relative intensity noise (RIN) of the generated supercontinuum was measured over 1200–1700 nm and radiofrequency range from 1MHz–40 MHz band, where noise is due to the amplification of the quantum noise by the nonlinear processes involved. Among the three pump configurations, ring cavity seeded MOPA pumped SC consistently produced the lowest integrated RMS RIN, approximately 2.5% over the measured MHz band, compared to ⁓5% for FBG-based pumps. This reduction can be attributed to the lower intrinsic intensity noise of the ring-cavity Yb-fiber source, highlighting pump laser architecture as a key determinant of noise transfer in CW-pumped CRRFL supercontinuum systems.