Search

Self-parametric amplification is employed as a novel gain mechanism in ultrafast fibre lasers, which transfers energy from the spectral tails to the center within the laser field. The laser outputs three pulses with different spectra.

The averaged intra- and inter-modal effective nonlinear coefficients in few-mode fiber are experimentally measured by exploiting self-phase and cross-phase modulation effects. Results are in accordance with predictions using Manakov equation.

We demonstrate pulse compression using ultra-silicon-rich nitride grating devices. Frequency chirp from a waveguide is temporally synchronized by a dispersive grating to achieve temporal compression by a factor of 4.3. When reversed, spectral compression of 2.3× is achieved.

We numerically and experimentally demonstrated the generation flat-spectrum wideband chaos with efficient bandwidth of several tens of GHz and perfect time delay signature suppression using external-cavity semiconductor laser subject self-phase modulation and dual optical feedback.

Stable UV-extended supercontinuum generation by self-action of Nd:YVO SHG-picosecond pulses in bulk solid and liquid materials is demonstrated. The continuum properties show a strong dependence on the incident beam focusing parameters and SHG-phase mismatch.

We propose a phase-preserving multilevel amplitude regeneration scheme based on Mach-Zehnder interferometers. For geometrically shaped 16-QAM signals, the EVM performance is improved by 2.5dB and consequently the higher SNR tolerance is achieved for regenerative links.

We discuss simultaneous and independent 2R regeneration of many WDM channels, enabled by a group-delay-managed nonlinear medium, in which high intra-channel nonlinearity can be accumulated without suffering from the nonlinear inter-channel crosstalk.

We present a 350-W 940-fs thin-disk oscillator. We achieve this new record-high average power ultrafast oscillator through vacuum operation, multiple passes on the disk, and large pump spot. Systematic power-scaling through multi-pass cavities is discussed.

We propose chalcogenide all-solid hybrid microstructured optical fibers for mid-infrared supercontinuum generation pumped with lasers at short wavelengths. The supercontinuum spectra are from 1.3 to 7 µm and highly coherent.

We report an all-PM fiber laser based on a mode-locked seeder and only two amplification stages delivering 35 fs pulses with an energy of 30nJ and an average power of 1.13 W at telecom wavelength.

We report, as a direct consequence of time refraction, an unprecedentedly large and tunable frequency translation of an optical beam over 14.8 THz bandwidth at infrared frequencies using an epsilon-near-zero material of subwavelength thickness.

We demonstrate the optical pulse compression of 2ps laser down to 230fs pulse resulting in 8.7 times compressed using a USRN waveguide. The process is facilitated by high-order soliton formation arising from a large nonlinear parameter and anomalous group velocity dispersion.

We present a compact scheme for generating sub-10-fs, CEP-stable pulses. The output of a CEP-stable ultrabroadband 3-mJ, 12-fs Ti:Sa amplifier is spectrally broadened in bulk and compressed, resulting in sub-10 fs pulses.

We measure parameters of a stable supercontinuum generated in long YAG crystal, driven by 3 ps pulses at 1030 nm and evaluate the impact of initial conditions on supercontinuum stability.

We experimentally demonstrate a broadband chaos generation using semiconductor laser subject to self-phase-modulation and microsphere resonator, and a subsequent fast physical random bit generation beyond 300-Gbps by using the broadband chaos as entropy source.

Using intense quasi-subcycle THz sources, we demonstrate various highly nonlinear THz effects in semiconductors. We also describe experimental results that show the first clear evidence of THz-induced disassembly of DNA nanostructures in solution.

Experimental observation of rogue waves in temporally stretched optical pulse train from a linear cavity mode-locked fiber laser has been reported. Rogue waves appeared when the output spectral width was comparable to the filter bandwidth.

We experimentally demonstrate WDM capable Raman-assisted low-noise phase-sensitive amplifier with up-to ∼26dB gain for 35 channels at 40GHz spacing using FBG phase tuning of single pump. 16QAM constellation shows gain linearity for multi levels formats.

We report the first LiGaS2-based mid-IR OPCPA, delivering 13.8µJ, 10kHz, 145fs, 9µm pulses. A 5-mm thick KrS5 crystal is employed to further compress the pulse to the 45fs (1.5 cycle) pulse duration.

We propose and experimentally demonstrate enhanced interactions among dissipative Kerr solitons in a nonlinear microresonator, via using a beating laser to incur controllable background modulation of the intracavity waveform. Our scheme enables deterministic single-soliton generation.

We demonstrate an ultraviolet frequency comb ranging from 360 to 420 nm based on spectrum translation from a visible supercontinuum in an aluminum nitride nano-scale waveguide with an engineered quadratic nonlinearity.

High power beam combinable fiber lasers are basic modules for developing high power beam-combined fiber laser system such as coherent beam combining and spectral beam combining, in which narrow-linewidth operation are their essential property. In the present talk, we will review the research progress on high power beam combinable fiber lasers, then we will demonstrate our recent progress in our group: we have achieved a 4 kW level narrow-linewidth fiber laser based on tandem pumping scheme, which is the power record of beam combinable fiber lasers to the best of our knowledge. The spectral linewidth account for 90% power is ~ 0.89 nm at full power.

We investigate the use of 4D constant modulus modulation format combined with subcarrier modulation. Compared to the star-8QAM format, the proposed format has an improved performance gain from reducing the baud rate down to 1 GBd.

We successfully demonstrated real-time 400G (64GBaud DP-16QAM) single-carrier ultra-efficient 1.2Tb/s superchannel (6.25bit/s/Hz) over new ultra-low loss large Aeff terrestrial fiber with long term error-free performance over 150km single-span and 250km (2 spans) using only EDFAs.

We propose a conjugate nonlinear-optical loop mirror pair scheme (Conj-NOLM) for phase-preserving multilevel amplitude regeneration, by cascading two identical NOLMs with an intermediate phase conjugation stage. Q2-factor improvements of 2.42dB are achieved for 16-QAM signals.

We describe an SU(1, 1) interferometer based on highly nonlinear optical fiber, attaining >97% peak interference visibility and >90% visibility over a 554 GHz optical band.

We present the experimental development of dispersion-engineered tellurite fibers based on a simple step-index profile for mid-infrared supercontinuum generation. A supercontinuum spanning from 1.5 to 4.5 μm is obtained in a 12-cm-long fiber.

We demonstrate a fiber-based ultrafast source generating 450-mW, sub-100-fs pulses centered at 1250 nm by implementing self-phase modulation enabled spectral selection. This source is ideal for harmonic generation microscopy in human skin.

A new scheme capable of generating tunable relativistically intense, single-cycle pulses in the spectral range of 5-14 µm with a 1.7% conversion efficiency through asymmetric self-phase modulation in a tailored plasma density structure is proposed.

We present an analysis on the optimization of nonlinear amplification in the anomalous dispersion regime, resulting in high-quality 50 fs-pulses at 20 W of average power and 80 MHz repetition rate.

We demonstrate the generation of 1 mJ, 85 fs, 2.5 µm pulses with 300 nm of available bandwidth at 1 kHz of repetition rate from a Chirped Pulse Amplifier based on the Cr2+:ZnSe gain medium.

We demonstrate temporal-based single-shot ns pulse characterization on a nanosecond 1064-nm Yb-doped fiber amplifier system. Both the amplitude and phase stability of bursts containing 35 1-ns pulses are measured and analyzed.

Experimental observation of polarization modulation instability in all-normal dispersion photonic crystal fibers is reported. Stokes and anti-Stokes sidebands with spectral shift of 40 nm were observed when the fiber was pumped at 1064 nm. Experimental results are baked by a vectorial four-wave mixing model.

We experimentally and numerically investigated dispersion engineering of amplification of erbium-fiber based comb. Spectral narrowing in a fiber amplifier increased the effective gain and enhanced the peak power at fiber-based dispersion compensator output.

□ The author would like to thank colleagues at Fujitsu for collaboration, discussion and contribution: □ T. Ikeuchi, I. Kim, M. Sekiya, T. Hoshida, S. Oda, T. Yamauchi, H. Nakashima, T. Oyama, H. Ooi, Y. Aoki, Z. Tao.

The influence of temporal phase control of ultra-broadband femtosecond laser pulses on contrast enhancement in nonlinear imaging and its application in a custom built multimodal microscope, is presented in this study.

We will present the advantages of the single-crystal-fiber (SCF) concept and review the main results obtained in ultrashort multi-stages Yb:YAG SCF amplifiers for high average power (100W) and high energy (mJ) regimes using Divided-Pulse-Amplification technic.

We present and compare highly robust Yb-doped monolithic amplifier and -oscillator setups in 20/400 μm geometry achieving signal powers of 3.5 kW and 5 kW in a bidirectional pumping scheme while maintaining single mode beam quality of M2 ~ 1.3.

We solve the long-standing discrepancy between the theoretically predicted and experimentally observed performance of nonlinear-optical refraction in graphene. Hereto we study self-phase modulation in silica-core waveguides covered with graphene.

We use a phase-mismatched χ(2) crystal to cancel the nonlinearities caused by intracavity air. We obtain 153 W average output power in an air-filled cavity, which is a record value for non-vacuum/non-helium SESAM modelocked lasers.

We studied the format conversion from 16QAM to single symbol rate doubled QPSK modulation using FWM, linear polarizer, and pulse width compressor. Bit-error rate performance is numerically verified, resulting in error-free format conversion.

We report the first observation of Kerr self-focusing of 3 ps TW CO 2 laser pulses in atmosphere. A centimeter diameter, 30m long, 10-μm light channel containing a few Joules of energy is generated and characterized.

A rigorous mathematical model is developed to study the Raman effect in silicon photonic crystal waveguides. We show how enhanced signal amplification without pulse distortion is achieved by adequately tuning the pulse group velocities.

We exploit cascaded-χ(2) nonlinearities in an intracavity second-harmonic-generation crystal to cancel the self-phase modulation from air in a thin-disk oscillator. We obtain 210-W output power, a record value for a SESAM-modelocked laser operated in air.

Dissipative Kerr soliton formation with unprecedented detuning control precision is demonstrated using an auxiliary-laser-heating method to suppress cavity thermal disturbance. New existence region of dissipative Kerr soliton in low pump power regime is originally discovered.

Spectral phase shift of ultra-broadband pulses due to inversion was measured along the two axes of Ti:Sapphire at room and cryogenic temperatures. Results are crucial for CEP stabilization and compression of high energy few-cycle pulses.

We demonstrate new dissipative Kerr soliton formation route with red-detuned pump entrance and observe soliton bursts in microcavity. We show that ignition of soliton burst requires much less pump tuning than conventional blue-pump-entry soliton generation.

Silicon-on-insulator waveguides covered with graphene in different lengths have been fabricated. We demonstrated the enhanced self phase modulation and Kerr nonlinearity in graphene-integrated silicon waveguides.

We measure the chirp in extreme ultraviolet high-harmonics from bulk MgO crystals pumped by strong near-infrared pulses using the two-color approach. By performing measurements in both reflection and transmission we separate propagation effects.

We report the generation of high-power tunable mid-infrared laser pulses at 1 – 4 µm region with duration of less than 70 fs, by a dual-chirped optical parametric amplification (DC-OPA) scheme. DC-OPA can provide TW-scale mid-infrared pulse efficiently.