High-power visible-enhanced all-fiber supercontinuum generation in a seven-core photonic crystal fiber pumped at 1016 nm

Partial Amplification of Octave-Spanning Supercontinuum in the Spectral Region of 1.5–2.2 μm

Octave-spanning supercontinuum conversion in three different rare-earth doped fiber amplifiers have been investigated. Using an erbium amplifier, it turned out to increase the output power to 445 mW with a spectral width of 1250 nm. For a thulium amplifier, an average output power of 390 mW and a spectral width of 569 nm was obtained. Additionally, for holmium, the average output power was 724 mW with a spectral width of 450 nm. For all cases, the output pulses envelope did not exceed 0.72 ns.

High Power All-Fiber Supercontinuum System Based on Graded-Index Multimode Fibers

An all-fiber supercontinuum source based on graded-index multimode fibers is reported. The supercontinuum source is based on a homemade mode-locked oscillator and a three-stage picosecond amplifier, which obtained the supercontinuum by a graded-index multimode fiber. The laser output with a spectral range of 480–2440 nm, an average power of 25 W, and a repetition frequency of 8.27 MHz is obtained. To the best of our knowledge, this is the highest average power for generating a supercontinuum with an all-fiber structure based on the graded-index fiber. The effects of GRIN fiber length and different pump peak powers on the supercontinuum generation are also verified. The results showed that the graded-index multimode fiber can effectively obtain a supercontinuum with high power.

Ultra-broadband supercontinuum covering a spectrum from visible to mid-infrared generated by high-power and ultrashort noise-like pulses

To facilitate a fiber-based supercontinuum generation system, single-mode fibers with different cutoff wavelengths are introduced to serve as shortpass filters to replace conventional reflective or transmissive filters. Meanwhile, an ytterbium-doped fiber amplifier is adopted to amplify the filtrated pulses, scaling their average power to the watt level up to 4.33 W. Through this approach, ultrashort high-power laser pulses of 1.56 µm and 1.06 µm wavelengths, which are commonly used in optical communications and industrial applications, can be generated by this single system. Furthermore, it is found that the noise-like pulses still maintain their temporal features, even after they undergo multiple optical processes including amplification, supercontinuum generation, and filtration. After that, the generated pulses at 1.06 µm were launched into a photonic crystal fiber to generate a supercontinuum of 1.85 W covering a spectral range from 560 nm in the visible region to 3.5 µm in the mid-infrared region. This is one of the widest records of spectrum in broadband supercontinuum generation.

High-efficiency ultra-compact near-infrared supercontinuum generated in an ultrashort cavity configuration

We report a novel method to generate near-infrared supercontinuum (SC) in an ultrashort cavity configuration with only 11.5 m. With the continuous laser diode pump, a near-infrared SC with 26.8 W average output power and a spectrum ranging from 900 nm to 2000nm is demonstrated, and the laser diode pump to supercontinuum conversion efficiency is up to 60%. The spectral and power characteristics of the generated SC under different lengths of germanium-doped fiber (GDF) were carefully studied. This near-infrared SC generation method has the advantages of simple structure, low cost and good stability and also possesses the shortest fiber laser cavity length ever reported to the best of our knowledge.

Supercontinuum generation of 314.7 W ranging from 390 to 2400 nm by tapered photonic crystal fiber

To consider both high-power handling and blue-extended supercontinuum (SC) generation, a long-tapered photonic crystal fiber is pumped by a high-power laser source. An SC ranging from 390 to 2400 nm with 314.7 W output power is obtained. A spectral component below 960 nm accounts for 36.1% of the total output power, exceeding 113.5 W, with a spectral flatness within 16 dB. To the best of our knowledge, this is the first time an SC coverage of all visible wavelengths with more than 300 W output power has been achieved. This result increases the output power of the SC covering the visible range by a factor of three.

Micro-joule level visible supercontinuum generation in seven-core photonic crystal fibers pumped by a 515 nm laser

A visible supercontinuum (SC) with high energy is of vital importance to applications in remote sensing and hyperspectral light detection and ranging. A fiber laser with a wavelength of 1030 nm is frequency doubled through a LBO (LiB₃O₅) crystal, and a high-energy 515 nm laser is obtained after wavelength conversion. Two kinds of seven-core photonic crystal fibers (PCFs) are used in this Letter. One is a uniform seven-core PCF (USC-PCF), and the other is a tapered seven-core PCF (TSC-PCF). Pumped by a 515 nm laser with a pulse width in nanosecond level, an SC covering 400 to 900 nm is efficiently generated in both PCFs. A maximum energy of 4.24 μJ is obtained in a USC-PCF. To prevent fiber damage of the coupling fiber end, the TSC-PCF which contains a transition fiber and a meters-long small core fiber is fabricated. One end of the transition fiber possesses a larger core diameter, and the pump laser can be coupled into the TSC-PCF without fiber damage. The meters-long small core fiber has the same core size with a USC-PCF and is utilized as the nonlinear medium to generate an SC. The dispersive wave in the short wavelength band is excited when more energy is shed into a fiber anomalous dispersion region. Up to 15th-order Raman peaks are observed during the SC evolution process.

Hundred-watt level linearly polarized visible supercontinuum generation

An all-fiber linearly polarized supercontinuum (SC) laser source with 93 W average output power and spectrum ranging from 520 nm to 2300 nm is experimentally demonstrated. The linearly-polarized SC is generated in a piece of 2.6 m long polarization-maintaining photonic crystal fiber (PM-PCF), pumped by a polarization-maintaining picosecond Yb-doped master oscillator power amplifier (PM-MOPA). The source exhibits a flat spectrum from 600 nm to 1880 nm at -10 dB level except for the residual pump peak. A new method is proposed to measure the polarization extinction ratio (PER) of each single wavelength of the broadband supercontinuum at a high-power level, resulting in larger than 16 dB PER from 900 nm to 1600 nm and larger than 15 dB PER from 540 nm to 650 nm. To our knowledge, this is the first demonstration of hundred-watt level linearly polarized visible SC and the first demonstration of PER measurement of each single wavelength within such a wide spectrum range.

High power LP11 mode supercontinuum generation from an all-fiber MOPA

High power LP₁₁ mode supercontinuum is generated from 25/250 large mode area (LMA) fiber. A mechanical long period grating (LPG) is utilized to control the transverse modes in the LMA fiber to realize the LP₁₁ mode supercontinuum generation in a master oscillator power amplifier (MOPA) configuration. The generated LP₁₁ mode supercontinuum covers the spectral range from ~900 nm to ~2100 nm with a -30-dB spectral width of ~1200 nm and 50% optical to optical conversion efficiency. The seed laser produces picosecond pulses with 1 MHz repetition rate at the wavelength of 1060 nm. After multi-stage amplification in ytterbium-doped fibers, the average output power is scaled to 54.51 W and 56.79 W respectively for LP₁₁ and LP₀₁ mode, accompanying supercontinuum generation. Obvious difference of supercontinuum generation between the LP₀₁ and LP₁₁ modes is experimentally observed due to the different dispersion characters.