A5019176809- Advanced Fiber Laser Technologies
- Advanced Fiber Optic Sensors
- Photonic Crystal and Fiber Optics
- Photonic and Optical Devices
- Laser Material Processing Techniques
- Quantum Information and Cryptography
- Photorefractive and Nonlinear Optics
- Quantum optics and atomic interactions
- Solid State Laser Technologies
- Optical Coatings and Gratings
- Neural Networks and Reservoir Computing
- Quantum Mechanics and Applications
- Semiconductor Quantum Structures and Devices
- Surface Roughness and Optical Measurements
- Advanced Photonic Communication Systems
- Advanced Surface Polishing Techniques
- Laser-Matter Interactions and Applications
- Mechanical and Optical Resonators
- Optical Network Technologies
- Semiconductor Lasers and Optical Devices
- Advanced MEMS and NEMS Technologies
Friedrich Schiller University Jena
2016-2025
Schiller International University
2015
Fraunhofer Institute for Applied Optics and Precision Engineering
2013
Abstract High-dimensional photon states (qudits) are pivotal to enhance the information capacity, noise robustness, and data rates of quantum communications. Time-bin entangled qudits promising candidates for implementing high-dimensional communications over optical fiber networks with processing approaching those classical telecommunications. However, their use is hindered by phase instability, timing inaccuracy, low scalability interferometric schemes needed time-bin processing. As well,...
Abstract Modern quantum technologies have matured such that they can now be used in space applications, e.g., long‐distance communication. Here, the design of a compact true single photon source is presented enhance secure data rates satellite‐based key distribution scenarios compared to conventional laser‐based light sources. The fluorescent color center hexagonal boron nitride. emitter off‐resonantly excited by diode laser and directly coupled an integrated photonic processor routes...
We report the inscription of low-loss fiber Bragg gratings using focused femtosecond (fs) pulses and a continuous core-scanning technique. This direct-write technique produces high-fidelity Type I-IR that share inherent advantages other methods, such as point-by-point (PbP) method, for which grating period is free parameter. However, here we demonstrate an order magnitude improvement in scattering loss compared to PbP gratings, level comparable with phase-mask-based fs inscription. A...
We present highly robust fiber Bragg gratings (FBGs) in passive large-mode-area fibers for kilowatt laser systems. The were inscribed directly through the coating using near-infrared femtosecond pulses and then implemented an all-fiber ytterbium-doped single-mode oscillator setup reaching up to 5 kW signal output power. untreated cooled FBGs showed thermal coefficients as low ${1}\;{\rm K}\;{{\rm kW}^{ - 1}}$1KkW-1, proving excellent qualification implementation into high-power setups.
Highly localized fiber Bragg gratings can be inscribed point-by-point with focused ultrashort pulses. The transverse localization of the resonant grating causes strong coupling to cladding modes high azimuthal and radial order. In this paper, we show how reflected fully analyzed, taking their vectorial nature, orientation degeneracies into account. observed modes' polarization intensity distributions are directly tied dispersive properties abrupt transitions in strongly correlated changes strengths.
Point-by-point (PbP) inscription of fiber Bragg gratings using femtosecond laser pulses is a versatile technique that currently experiencing significant research interest for and sensing applications. The recent demonstration apodized this provides new avenue investigation into the nature refractive index perturbation induced by PbP modifications, as are sensitive to variation in average background along grating. In work we compare experimental results Gaussian- sinc-apodized coupled-mode...
We investigate the high-power durability of fiber Bragg gratings written directly into an ytterbium-doped large mode area using ultrashort laser pulses. The were successfully integrated as a high reflector oscillator setup reaching up to 1.9 kW signal output power with efficiency 87%. Defect states induced during inscription process could be drastically reduced by self-annealing resulting in stable performance.
We detail the design and performance of a high efficiency in-band pumped thulium fiber amplifier operating at 100 W level. Using novel pumping architecture based on three incoherently combined oscillators 1904 nm seed laser tunable from 1970-1990 nm, efficient amplification is demonstrated in dopant concentration 25/65/250 µm fiber. Here we use 65 pedestal surrounding core as pump cladding to increase overlap improve overall absorption. Up 89% slope obtained with ∼100 output power 1990 nm....
Abstract Shaped laser pulses have been remarkably effective in investigating various aspects of light–matter interactions spanning a broad range research. Chirped exhibiting time‐varying frequency, or quadratic spectral phase, form crucial category the group shaped pulses. This type made ubiquitous presence from spectroscopic applications to developments high‐power technology, and nanophotonics quantum optical communication, ever since their introduction. In case technologies recently,...
The first steps towards the development and characterization of next-generation chirped volume Bragg gratings (CVBGs) by means fs laser inscription were made. Based on phase mask technique we realized CVBGs in fused silica with a 3 × mm 2 aperture length almost 12 chirp rate ∼190 ps/nm around central wavelength 1030.5 nm. Strong mechanical stresses induced serious polarization distortions radiation. We show possible approach to solution this problem. change linear absorption coefficient...
We report on the inscription of fiber Bragg gratings using femtosecond laser pulses and phase-mask technique. The wavefront is variably tuned with a spatial light modulator (SLM). By applying Fresnel lenses different focal lengths, period could be shifted. A linear change grating for FBG inscribed third-order deformed quadratic-period behavior fourth-order verified experimentally first time.
We report on the detailed investigation of core to cladding mode coupling in femtosecond-written long period fiber gratings (LPFG). It is shown that excitation higher-order modes with strong selectivity and high precision possible. The behavior several gratings, as well its dependence modified cross-section, determined theoretically confirmed experimentally by spectral response. presented tool paves way for a completely new class tailored LPFGs different integrated devices.
We present efficient long period fiber gratings written with femtosecond laser pulses at 800 nm and an amplitude mask, to the best of our knowledge, for first time. The measured transmission spectra depict strong resonances, while total grating length polarization-dependent loss could be significantly reduced compared previous results. Two are exemplarily shown—one in a standard single mode, one large-mode-area revealing predictable spectrum without intermediate peaks due suppression...
The average output power of fiber lasers have been scaled deep into the kW regime within recent years. However a further scaling is limited due to nonlinear effects like stimulated Raman scattering (SRS). Using special characteristics femtosecond laser pulse written transmission gratings, it possible realize notch filter that mitigates efficiently this negative effect by coupling wavelength from core cladding fiber. To best our knowledge, we realized for first time highly efficient gratings...
We present and compare the performance of bidirectionally pumped Yb-doped monolithic amplifier oscillator setups in 20/400 μm geometry tested up to signal powers 3.5 kW 5 without occurrence transverse mode instabilities maintaining a single beam quality M<sup>2</sup> ~ 1.3. The scaling was primarily limited by nonlinear effect Stimulated Raman Scattering. This contribution contains detailed analysis temporal spectral behavior both configurations. results show excellent feasibility...
Ultrashort laser pulses are used to inscribe volume Bragg gratings (VBGs) into fused silica. These VBGs demonstrate excellent performance for the external stabilization of diode bars. The stabilized system emits at a wavelength 969 nm with signal width (FWHM) 100 pm and shows spectral drift as low 24 change in output power 45 W grating surface area 10 mm2.
We demonstrate and characterize a highly linearly polarized (18.8 dB) narrow spectral emission (<80 pm) from an all-fiber Tm laser utilizing femtosecond-laser-written fiber Bragg gratings. Thermally-dependent anisotropic birefringence is observed in the FBG transmission, effects of which enable both generation elimination output. To our knowledge, this first detailed study such thermal femtosecond-written FBGs.
We demonstrate the fabrication of aperiodic fiber Bragg gratings (AFBGs) for their application as filter elements. Direct inscription was performed by focusing ultrashort laser pulses with an oil-immersion objective into core and utilizing line-by-line technique flexible period adaptation. The AFBGs inscribed allow suppression 10 lines in a single grating are excellent agreement simulations based on specific design. Applications astronomy hydroxyl emission discussed.
We present and compare highly robust Yb-doped monolithic amplifier -oscillator setups in 20/400 μm geometry achieving signal powers of 3.5 kW 5 a bidirectional pumping scheme while maintaining single mode beam quality M2 ~ 1.3.
We present the tuning of dispersion properties a femtosecond (fs) laser inscribed chirped fiber Bragg grating (CFBG), realized by selectively modifying refractive index already CFBG fs post-processing. This Letter demonstrates for first time, to best our knowledge, flexible approach tailoring higher-order terms via post-processing selected regions, thus paving way, e.g., applications in management ultrashort pulse lasers.
We report the development of a widely tunable mode-locked thulium-doped fiber laser based on robust chirped Bragg grating (CFBG). By applying mechanical tension and compression to CFBG, an overall tunability 20.1 nm, spanning from 2022.1 nm 2042.2 was achieved. The observed pulse train this has repetition rate 9.4 MHz with average power 12.6 dBm duration between 9.0 ps 12.8 ps, depending central wavelength. To best our knowledge, is first demonstration operating beyond 2 µm using CFBG as...
Modern quantum technologies have matured such that they can now be used in space applications, e.g., long-distance communication. Here, we present the design of a compact true single photon source enhance secure data rates satellite-based key distribution scenarios compared to conventional laser-based light sources. Our is fluorescent color center hexagonal boron nitride. The emitter off-resonantly excited by diode laser and directly coupled an integrated photonic processor routes photons...
The period of fiber Bragg gratings is adapted by shaping the wavefronts ultrashort laser pulses applied in a phase mask inscription technique. A specially designed deformable mirror, based on dielectric substrate to withstand high peak powers, utilized deform wavefront. shift about 11 nm demonstrated for wavelength around 1550 nm.
We present the inscription of narrow-linewidth fiber Bragg gratings (FBGs) into different types multicore fibers (MCFs) using ultrashort laser pulses and phase mask technique, which can act as notch filters. Such filters are required, e.g., to suppress light emitted by hydroxyl in Earth’s upper atmosphere, disturbs ground-based observation extraterrestrial objects near infrared. However, a commercially available seven-core showed quite large core-to-core deviation resonance wavelength up...