ABSTRACT
We investigate hollow-core fibers for fiber delivery of high power ultrashort laser pulses. We use numerical techniques to design an anti-resonant hollow-core fiber having one layer of non-touching tubes to determine which structures offer the best optical properties for the delivery of high power picosecond pulses. A novel fiber with 7 tubes and a core of 30µm was fabricated and it is here described and characterized, showing remarkable low loss, low bend loss, and good mode quality. Its optical properties are compared to both a 10µm and a 18µm core diameter photonic band gap hollow-core fiber. The three fibers are characterized experimentally for the delivery of 22 picosecond pulses at 1032nm. We demonstrate flexible, diffraction limited beam delivery with output average powers in excess of 70W.
ABSTRACT
We demonstrate a compact fibre-based laser system at 2.05 microns stabilized to a CO2 transition using frequency modulation spectroscopy of a gas-filled hollow-core fibre. The laser exhibits an absolute frequency accuracy of 5 MHz, a frequency stability noise floor of better than 7 kHz or 5 × 10-11 and is tunable within ±200 MHz from the molecular resonance frequency while retaining roughly this stability and accuracy.
ABSTRACT
Gas-filled hollow-core photonic crystal fibers are used to stabilize a fiber laser to the 13C2H2 P(16) (ν1+ν3) transition at 1542 nm using saturated absorption. Four hollow-core fibers with different crystal structure are compared in terms of long term lock-point repeatability and fractional frequency instability. The locked fiber laser shows a fractional frequency instability below 4 × 10(-12) for averaging time up to 10(4) s. The lock-point repeatability over more than 1 year is 1.3 × 10(-11), corresponding to a standard deviation of 2.5 kHz. A complete experimental investigation of the light-matter interaction between the spatial modes excited in the fibers and the frequency of the locked laser is presented. A simple theoretical model that explains the interaction is also developed.
ABSTRACT
1178 nm single-frequency amplification by Yb doped photonic bandgap fiber has been demonstrated. 24.6 W output power and 12 dB gain were obtained without parasitic lasing and also stimulated Brillouin scattering. 1.8 dB suppression of Brillouin gain by an acoustic antiguiding effect has been found in the Yb doped photonic bandgap fiber.
ABSTRACT
An ytterbium-doped solid-core photonic bandgap fiber oscillator in an all-fiber format is investigated for high power at an extreme long wavelength. The photonic bandgap fiber is spliced with two fiber Bragg gratings to compose the cavity. The sharp-cut bandpass distributed filtering effect of the photonic bandgap fibers efficiently suppresses amplified spontaneous emission in the conventional high-gain region. Fine adjustment of the short cut-off wavelength by coiling with tighter diameter is performed to suppress parasitic lasing. A record output power of 53.6 W with a slope efficiency of 53% at 1178 nm was demonstrated.
Subject(s)
Amplifiers, Electronic , Fiber Optic Technology/instrumentation , Oscillometry/instrumentation , Refractometry/instrumentation , Yttrium/chemistry , Equipment Design , Equipment Failure Analysis , Light , Scattering, RadiationABSTRACT
The transmission properties of five types of hollow-core photonic bandgap fibers (HC-PBFs) are characterized in the telecom wavelength range around 1.5 microm. The variations in optical transmission are measured as a function of laser frequency over a 2 GHz scan range as well as a function of time over several hours. The influence of these variations on spectroscopy of molecules in a HC-PBF is simulated.
