Title :
Optical mixing in thin YBa/sub 2/Cu/sub 3/O/sub 7-x/ films
Author :
Zorin, M. ; Gol´tsman, G.N. ; Karasik, B.S. ; Elantev, A.I. ; Gershenzon, E.M. ; Lindgren, M. ; Danerud, M. ; Winkler, D.
Author_Institution :
Moscow State Pedagogical Univ., Russia
fDate :
6/1/1995 12:00:00 AM
Abstract :
High quality, j/sub c/ (77 K)>10/sup 6/ A/cm/sup 2/, epitaxial YBa/sub 2/Cu/sub 3/O/sub 7-x/ films of 50 nm thickness were patterned into ten parallel 1 /spl mu/m wide strips. The film structure was coupled to a single-mode fiber. Mixer response was obtained at 0.78 /spl mu/m using laser frequency modulation and an optical delay line. Using two semiconductor lasers at 1.55 /spl mu/m wavelength the beating signal was used to measure the photoresponse up to 18 GHz. Nonequilibrium photoresponse in the resistive state of the superconductor was observed. Bolometric response dominates up to 3 GHz, after which the nonequilibrium response is constant up to the frequency limit of our registration system. Using an electron heating model the influence of different thermal processes on the conversion loss has been analyzed. Ways of increasing the sensitivity are also discussed.<>
Keywords :
barium compounds; high-temperature superconductors; optical frequency conversion; superconducting epitaxial layers; yttrium compounds; 0.78 micron; 1.55 micron; 3 to 18 GHz; YBa/sub 2/Cu/sub 3/O/sub 7/; beating signal; bolometric response; conversion loss; electron heating model; epitaxial YBa/sub 2/Cu/sub 3/O/sub 7-x/ films; laser frequency modulation; nonequilibrium photoresponse; optical delay line; optical mixing; resistive state; semiconductor lasers; sensitivity; single-mode fiber; thermal processes; Delay lines; Fiber lasers; Frequency modulation; Optical films; Optical mixing; Optical modulation; Optical sensors; Semiconductor films; Semiconductor lasers; Strips;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
