Photorefractive Effect in a Polymer Molecularly Doped with Low-Molecular-Weight Compounds

Abstract

This paper proposed an X-band 6-bit passive phase shifter (PS) designed in 0.18 m silicon-on-insulator (SOI) CMOS technology, which solves the key problem of high integration degree, low power, and a small size T/R module. The switched-topology is employed to achieve broadband and flat phase shift. The ESD circuit and driver are also integrated in the PS. It covers the frequency band from 7.5 to 10.5 GHz with an EMS phase error less than 7.5 ı . The input and output VSWRs are less than 2 and the insertion loss (IL) is between 8-14 dB across the 7.5 to 10.5 GHz, with a maximum IL difference of 4 dB. The input 1 dB compression point (IP 1dB / is 20 dBm.

Reversible and irreversible index gratings in a NPP-doped low-T<SUB>g</SUB> polymer composite

“…This value for E Q is in reasonable agreement with the value 40:7 V=mm obtained from the TBC experiments. It should be pointed out that the amplitude of PR eå ect in our sample lm is much larger than with NPP-doped other matrices [12][13][14][15] comparable with those reported for azo-dye-doped composites [7,20]. This suggests that NPP also has large orientational anisotropy [18].…”

“…Figure 2 shows the measured TBC coeae cient plotted against the applied electric eld. At 85 V=·m, the TBC coeae cient ¡ was about 140 cm -1 , which was much higher than that of other PR matrices [12][13][14][15] doped with the NPP. This strong enhancement can be attributed to the excellent photoconductivity of the PVK:TNF complex [6,7,17].…”

“…Doped with various azo-dyes as electro-optic (EO) chromophores, the composites exhibit a strong two-beam coupling eå ect [7] and a few milliseconds PR response time [8,9]. The high photorefractivity in these samples is attributed to a so-called orientational enhancement eå ect [10].…”

“…The high photorefractivity in these samples is attributed to a so-called orientational enhancement eå ect [10]. N-(4-nitrophenyl)-(l)-prolinol (NPP), one of the excellent nonlinear optical chromophore [11], has previously been doped in several low T g polymer composites as PR materials [12][13][14][15]. However, the reported photorefractivity was relatively small due to the poor photoconductivity of the matrix [13].…”

Reversible and irreversible index gratings in a NPP-doped low-Tgpolymer composite

“…Doped with various azo-dyes as electro-optic (EO) chromophores, the composites exhibit a strong two-beam coupling effect [7] and a few *e-mail: qhgong@ibm32Oh.phy.pku.edu.cn milliseconds PR response time [8,9]. The high photorefractivity in these samples is attributed to a so-called orientational enhancement effect [lo].…”