Higher-order Soliton Compression Research Articles

Higher-Order Soliton Compression of Optical Pulses from 5 ps to 20 fs by a 15.1-m-long Single-Stage Step-like Dispersion Profiled Fiber

It has been successfully demonstrated to compress 5 ps optical pulses down to 20 fs by a 15.1-m-long single-stage step-like dispersion profiled fiber (SDPF) through a series of the higher-order soliton compression processes in conjunction with a single and ordinary erbium-doped fiber preamplifier. The SDPF compressor contains two kinds of dispersion-flattened fibers (DFFs) at its end and was composed by fiber-splicing with an aid of an extremely careful cutback method. In addition, we have compared the measured compression profiles in the 20–100 fs range with simulation results calculated on the bases of a few elementary soliton models and some experimentally extracted parameters, which is aimed to investigate and clarify its compression mechanism. It was found out that the standard nonlinear Schroedinger equation works appropriately to some extent even in the 30–100 fs range for the DFF used here, although some difficulty exists in modeling the pulse width evolution in the sub-30 fs range as far as the parameters that we used are concerned.

Experimental studies of high order soliton compression effect and gain characteristics in femtosecond laser pulses Er 3+-doped fiber amplifier

Seed laser pulses with average power of 146 mu W and pulse duration of 480 fs were amplified to 14.5 mW. The pulse duration was compressed to 260 fs using 6 m high concentration E-r(3+)-doped fiber under forward pumping. The amplified signal pulse energy was 0.691 nJ (corresponding to a peak power of 2 657.7 W) and the repetition rate was 20.84 MHz. Spectrum breakup was observed simultaneously. The spectrum of pulses amplified by 3 m E-r(3+)-doped fiber remains a single peak under different pump power. The amplified pulse duration was compressed abnormally with the increasing pump power using the backward pumping; that is, the amplified pulses were compressed with the increasing pump power under low pump power. When the pump power reached 38 mW, the shortest amplified pulse duration was 309 fs. With further increase in pump power, the amplified pulses began broadening, accompanied by a single peak spectrum under different pump power.

Femtosecond Erbium-Doped Fiber Laser with Nonlinear Polarization Rotation and Its Soliton Compression

A continuous wave suppressed, uniformly repetitive pulse train as short as 136–145 fs has been successfully generated at a wavelength of 1.55 µ m from a new type of femtosecond erbium-doped fiber laser with nonlinear polarization rotation. The 145 fs pulse was shortened to 52 fs by using soliton narrowing and high order soliton compression. Soliton narrowing was achieved by amplifying the soliton pulse with an erbium-doped fiber amplifier, and a short length of dispersion-flattened fiber was used for further compressing the soliton.

Femtosecond Erbium-Doped Fiber Lasers and a Soliton Compression Technique

The lasing characteristics of an erbium-doped fiber laser with a nonlinear amplifying loop mirror (NALM) were investigated in detail. The NALM was pumped by 1.48 µm InGaAsP laser diodes and an output pulse as short as 124 fs was obtained at 1.56 µm. The 124-fs pulse was shortened to 50 fs by using adiabatic soliton narrowing and high order soliton compression. Soliton narrowing was achieved by amplifying the soliton pulse adiabatically with an erbium-doped fiber amplifier, and a short length of dispersion-flattened fiber was used for soliton compression. Soliton narrowing enabled us to succeed in generating a 98-fs pulse directly from a modified erbium-doped fiber laser.

Effects of group velocity dispersion on self/cross phase modulation in a nonlinear Sagnac interferometer switch

Time-resolved numerical analysis of a nonlinear Sagnac interferometer switch (NSIS) reveals that the combined effects of group velocity dispersion (GVD), self phase modulation, cross phase modulation, and pump-probe walk-off seriously degrade switching performance when the soliton number N of the pump pulse is under 5. This means that the peak power of short pump pulses cannot be reduced to less than the critical value at N>5 to prevent the effect of GVD. This restriction is more severe for pump pulses in the anomalous dispersion region than for those in the normal dispersion region because of higher-order soliton compression. System designs for time-division demultiplexers that use NSISs and picosecond pump pulses generated by a laser-diode coupled to erbium-doped fiber amplifiers are discussed. It is found that 1:32 demultiplexing from 160 to 5 Gb/s and 1:8 demultiplexing from 80 to 10 Gb/s with a switching contrast of more than 60 are possible using diode-laser-pumped 1- and 2-ps pump pulses, respectively.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Femtosecond soliton Raman ring laser

Pulses as short as 100 fs have been generated in standard single-mode optical fibre using a high-order soliton compression mechanism of the Raman component, synchronously excited in a ring laser geometry, pumped by a CW mode-locked Nd: YAG laser at 1.32?m.