As sputtering power of Mo target was increasing,surface roughness of Mo/Si film was increasing,characteristic diffraction peak of Mo species became stronger and stronger,furthermore, soft X-ray peak reflectivity of Mo/Si multilayers first increased and then reduced.
Using the couple mode theory, the reflection spectrum, the peak reflectivity and the reflection bandwidth of several typical fiber grating filters have been theoretically analyzed and numerically simulated.
The measurement results show that the multilayer mirrors designed and fabricated by this paper have practical reflectance. It needs to point out especially that at r=1.03nm the peak reflectance of the multilayer mirror is 10%.
The simulated annealing(SA) arithmetic was used in the optimized designing for several wavelength in soft x-ray region and the optimized optical parameters was gained,including the optimized period thickness,thickness ratio and peak reflectance.
It shows from the measured reflectivity spectrum of each sample that obvious reflectance peak occurs,but the center wavelength has some deviation from the designed value and the peak reflectance value is lower than expected.
A new dispersion compensator for multi-wavelength, the sampled chirped fiber Bragg grating(FBG),was fabricated. Its length is 10cm. I t has the 10 wavelength structures,with the space of neighbored wavelength 0.8nm .
In experiment,the chirp-free tuning wavelength of 20.1 nm,using part pure bending method was achieved. During the whole tuning process,the linearity was 0.9996,the 3-dB reflection bandwidth and the reflection index showed little variations less than 0.07 nm and 0.2 dB,respectively. There was almost no chirp appearing,and the experiment consists with theory analysis well.
The periodic thickness and structure of the multilayer were measured by X-ray diffractometer. The reflectivities of these multilayers were measured on beam line UE56/1-PGM at BESSY-II,Germany. The measured peak reflectivities were 7.50% and 6.12% for Cr/C and Cr/Sc multilayer mirrors,respectively.
in this work,we firstly enhanced the photosensitivity of general monomode fiber by hydrigen doping method,then fabricated fiber grating in it with UV-writing technology.The Bragg wavelength of the fiber grating we fabricated is 1552 um,the maximium reflectivty is about 48% and the full width at half maximium of the reflection peak is 1.2 um.
The fiber Bragg gratings (FBG) in domestic monomode photosensitive optical fibers were prepared in terms of a 248nm KrF excimer laser and a phase mask. Some FBGs with the reflectivity of 10% and the bandwidth of 0. 6nm were obtained.
A method for fabricating chirped fiber gratings using fiber Bragg gratings is presented. A Bragg fiber grating has been tapered by etching it in HF acid. A strain gradient along the grating was formed when a tension of 1.50 N was applied to the etched fiber grating and then a 15 mm long chirped fiber grating with a peak reflection of 92% and reflection full width at half maxmum (FWHM) width of 5 nm was fabricated.