We demonstrate a scheme based on cascade of lithium niobate intensity and phase modulators driven by specially tailored RF waveforms to generate an optical frequency comb with very high spectral flatness. In this Letter, we 10 GHz 38 lines within power variation below 1 dB. The number that can be generated is limited the handling capability modulator, scaled without compromising Furthermore, combs in our almost purely quadratic, which, as will demonstrate, allows for high-quality pulse...

High-power fiber lasers have seen tremendous development in the last decade, with output powers exceeding multiple kilowatts from a single fiber. Ytterbium has been at forefront as primary rare-earth-doped gain medium owing to its inherent material advantages. However, for this reason, are largely confined narrow emission wavelength region of ytterbium. Power scaling other regions lagged significantly, and large number applications rely upon diversity wavelengths. Currently, Raman only known...

A cladding pumped multicore erbium-doped fiber amplifier for simultaneous amplification of 6 channels is demonstrated. Peak gain over 32 dB has been obtained at a wavelength 1560 nm and the bandwidth measured 20-dB was about 35 nm. Numerical modeling also performed to study properties amplifier. The results experiment simulation are found be in good agreement.

High power fiber lasers operating at the 1.5micron wavelength region have attractive features like eye-safety and atmospheric transparency, cascaded Raman offer a convenient method to obtain high sources these wavelengths. A limitation scaling however has been lower conversion efficiency of lasers. We recently introduced architecture for applicable Here we demonstrate further using this new architecture. Using numerical simulations identify ideal conditions 1480nm laser with an output 301 W,...

Cascaded Raman fiber lasers based on random distributed feedback (RDFB) are proven to be wavelength agile, enabling high powers outside rare-earth doped emission windows.In these systems, by simply adjusting the input pump power and wavelength, highpower can achieved at any within transmission window of optical fibers.However, there two primary limitations associated with which in turn limits further scaling applicability.Firstly, degree conversion or spectral purity (percentage output...

We report on the recent development of multicore fiber amplifiers suitable for amplifying space division multiplexed signals. designed and constructed 7-core amplifiers, where cores could be pumped individually or simultaneously through cladding studied amplification noise properties these amplifiers. In core-pumped amplifier, net average gain was 25 dB, figure less than 4 dB. Using side-coupled pumping, over dB obtained in each a 40-nm bandwidth covering C-band. present results numerical...

The cascaded Raman fiber laser is a proven technology that provides wavelength agile high-power lasers outside the rare-earth emission windows. However, conventional lack agility due to use of fixed Bragg gratings. Recently, proposed based on random distributed feedback have provided grating-free solution enabling agility. With these lasers, wide tunability has been achieved. there are still limitations in scaling output power while maintaining high spectral purity conversion. Spectral...

We demonstrate a new Fourier pulse shaping apparatus capable of achieving simultaneous high resolution and broad bandwidth operation by dispersing frequency components in two dimensional geometry through use spectral disperser. show experimental results which significant improvements achievable waveform complexity (number controllable temporal/spectral features). also experiments line-by-line with optical combs. In this regime our configuration would allow enhancement the number lines may...

We introduce a new cascaded four-wave mixing technique that scales up the bandwidth of frequency combs generated by phase modulation continuous-wave (CW) laser while simultaneously enhancing spectral flatness. As result, we demonstrate 10 GHz comb with over 100 lines in dB which record 75 are within flatness 1 dB. The process increases initial CW factor five. broadband has approximately quadratic phase, is compensated upon propagation single-mode fiber, resulting train 940 fs pulses.

We demonstrate scaling of the effective area higher-order mode, Er-doped fiber amplifiers. Two mode fibers, one with 3800 μm(2) A(eff) in LP(0,11) and 6000 LP(0,14) are demonstrated. Output beam profiles show clean higher order modes, S(2) imaging measurements low extraneous content. CW pulsed amplifier experiments reported. Nanosecond pulses amplified to 0.5 mJ pulse energy MW peak power.

We demonstrate a new high efficiency architecture for cascaded Raman fiber lasers based on single pass amplifier configuration. Conversion is seeded at all intermediate Stokes wavelengths using multi-wavelength seed source. A lower power laser the conventional resonator provides convenient source providing necessary simultaneously. In this work we 1480nm pumped by an 1117nm Yb-doped with maximum output of 204W and conversion 65% (quantum-limited ~75%). believe both (relative to...

Random distributed feedback (RDFB) cascaded Raman fiber lasers (CRFLs) are simple, wavelength agile, and enable high-power outside emission bandwidths of rare-earth doped lasers. However, the spectral purity, defined as percentage total output power in desired Stokes band, relative intensity noise (RIN) these systems limited due to pump source used for conversion. RIN gets amplified transferred orders which causes incomplete conversion hence limits purity. Here, we demonstrate a...

Pulsed laser sources with nanosecond pulse duration are widely used in numerous noninvasive biomedical imaging applications, notably photoacoustic (PAI), an vivo modality. Multiple required to target the absorption features of multiple endogenous chromophores (optical absorbers inside tissues). We demonstrate a tunable pulsed cascaded Raman fiber continuously second near-infrared window (NIR-II, 1060–1600 nm) and through harmonic conversion visible (530–600 nm, limited by crystal...

Phase and/or intensity modulation techniques to broaden the Linewidth of an optical source are well known methods suppress stimulated Brillouin scattering (SBS) in fibers.A common technique used achieve significant bandwidth enhancement a simple fashion is phase modulate with filtered noise source.We will demonstrate here that, this case stochastic nature requires inclusion length dependent corrections SBS threshold enhancement.This effect becomes particularly for short fiber lengths most...

Cascaded Raman Fiber Lasers (CRFLs) are wavelength versatile sources that can provide power at any in the Near-Infrared (NIR) region. Conventional CRFLs with broadband feedback widely tunable but have broad line widths. A mechanism must be used to reduce broadening of linewidth without compromising tunability. Here, we propose use a dual combines all wavelengths, using flat cleave, filtered desired due grating filter. This allows substantial reduction up 6

We demonstrate a cascaded Raman fiber laser with record output power of 104 W at 1480 nm. achieve this an 1117 nm Yb-doped pumping conversion to 1480nm. Enhanced efficiency is achieved in the cavity using long wavelength cut-off which prevents further light and thus allowing for longer lengths. The single mode making it bright source core or cladding erbium-doped lasers.

Power scaling of continuous-wave, narrow-linewidth fiber lasers are limited by the onset stimulated Brillouin scattering (SBS) which manifests at threshold as potentially damaging, peak power, backward propagating pulses. While several SBS mitigation techniques exist, optical linewidth broadening through external phase modulation using white noise is predominantly used for its simplicity. But broadened line-shape non-ideal and has a slow roll-off resulting in increased seeding from...