We report on the experimental observation of sideband generation in a passively mode-locked erbium-doped fiber laser.
The fiber laser has a conventional ring-cavity configuration for passive mode locking based on nonlinear polarization
rotation. Self-starting and stable mode-locking operation is easily achieved in the laser. The output soliton pulses have a
duration of about 248 fs and a repetition rate of 13.7 MHz at 1565-nm wavelength. Detailed pulse dynamics of the laser
is measured under different operation conditions. Dip-type sidebands are observed on the soliton spectra of the laser,
which have clearly different characteristics to those of the conventional Kelly sidebands. The soliton operation of the
fiber laser is numerically simulated based on the coupled Ginzburg-Landau equations. The simulation results are
consistent with the experimental observations, which confirm that dip-type spectral sidebands can appear on the soliton
spectra of a uniform soliton-emission fiber laser.
Proc. SPIE. 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology
Electro-optic organic/polymer material is important for the fabrication of polymer integrated optic-electronic devices and
organic sensors. Recently, a novel organic high μβ value chromophore FFC have been synthesized by molecular design.
The absorption spectrum in 400-4000 cm-1 is measured for the material, and the measurement result shows that the
absorption loss is negligibly small. An organic/polymer high electro-optic activity material FFC/PSU is obtained by
dissolving guest FFC (wt. 20%) and a host polysulfone (PSU) in a solvent. The resolvability of cyclohexanone for the
material is satisfactory by comparison with other solvents experimentally, and the preparation of FFC/PSU thin film is
ease relatively. The materiel is poled by electric field-assisted contact poling, and the near optimum poling condition is
determined by adjusting poling parameters as pre-curing duration, poling temperature and poling voltage etc. The
electro-optic coefficient of the material is measured as high as 130pm/V by using the widely accepted simple reflection
technique. The investigation indicates that the FFC/PSU has excellent characteristics, such as high electro-optic
coefficient, low absorption loss, good thermal stability and capability for withstanding the subsequent process
techniques, suitable for the fabrication of high-performance integrated optic-electronic devices and sensors.
We present a numerical investigation of nonlinear propagation of chirp-free femtosecond pulses at 1550-nm wavelength
in a nonlinear photonic crystal fiber (PCF) with anomalous dispersion. The PCF has a second-order dispersion of - 8.67
×104 fs2/m, third-order dispersion of 2.8 x 105 fs3/m and nonlinear coefficient of 11 W-1km-1 at 1550 nm. The simulation
results show that efficient spectral compression of unchirped ultrashort pulses is induced in PCF when the input pulse
parameters satisfy the condition 0.6< N<0.7for the soliton number N. It is found that the compressed spectral width is
strongly dependent on the initial peak power and propagation length of the incident pulse. A compression factor up to 7
can be achieved. With the PCF, efficient spectral compression can take place in the wavelength range of 1530 ~ 1570 nm
covering the C-band. This spectral-compression scheme offers much promise for laser spectroscopy, optical information
technologies and high-power fiber-laser systems.
We present an investigation of spectral dynamics of an ultrashort-pulse Er-doped fiber laser mode-locked by a
semiconductor saturable absorber mirror (SESAM). The SESAM used has a saturable absorption modulation depth of
18%, a saturation fluence of 70 μJ/cm2 and a relaxation time of 10 ps at a wavelength of 1550 nm. Detailed pulse
dynamics of the laser are measured at different pumping levels, and the laser operation is linked to the characteristics of
the SESAM. It is observed that, as the pump power is increased, the laser operation changes from cw lasing, to self-Q
switching, Q-switched mode-locking, and then cw mode-locking. Self-starting and stable mode-locking operation is
achieved at a repetition rate of 12 MHz. The pulses with a width of 650 fs are produced at 1562-nm wavelength with a
pump power of 80 mW, and the corresponding spectral width is about 5.0 nm (FWHM). Based on the complex
Ginzburg-Landau equation, self-starting mode-locking process in the fiber laser is simulated, which confirms that
ultrashort pulses can be achieved. The calculated spectral characteristics of the mode-locked pulses are consistent with
the experimental observations.
Single mode propagation is an important requirement for optical waveguide devices for use with single-mode fiber, it
can reduce the coupling loss. In this paper, a technique is used for calculating the field distribution of the polymeric
Y-junction rib waveguide. The technique is based on the combination of the effective index method(EIM) and the
variational method(VM). It is mixed between the advantages of each method and avoided their disadvantages, where EIM
can make the calculations procedures simple but it has some difficult to find the field distribution, other wise, VM can be
used with very good accuracy to find the field distribution. An algorithm is implemented to study the effect of the
structure parameters on the field distribution of the polymeric Y-junction rib waveguide. In our simulation, the core layer
is PU-FTC (firstname.lastname@example.orgμm),the cladding layers were NOA73 (email@example.comμm) and Epoxylite9653 (firstname.lastname@example.orgμm).
The obtained single mode rid waveguide structure parameters are: the core thickness is 1.5μm, the rib height is 0.2μm,
the rib width is 5μm.
The microstructure with high fidelity is very important while being used as micro-optical component, because the
performance tightly depends on the profile quality of microstructure. Optical lithography method based on thick film
resist plays an increasing important role in fabrication for microstructure. However, the profile quality of the
microstructure is greatly affected by process parameters adopted in the experiment. In this paper, the effect of
illumination wavelength, gap distance and absorption coefficient on the profile quality after development has been
simulated, analyzed and discussed in detail, by using the model for thick film lithography. The simulated results show
that these process parameters have a great impact on the profile quality of microstructures, which it is helpful for process
optimization and profile control of thick film photolithography.