|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1994 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1993 : ¥1,600,000 (Direct Cost : ¥1,600,000)
In this research, wide separation of TE and TM slab-mode propagation constant being realized by multilayred thin-film structure, three dimentional (3D) optical wave guides, where single mode operation or polarization-maintaining operation are expected, are analyzed based on optical planar circuittheory. The corresponding 3D optical waveguides are fabricated, measured and compared with the analytical results. Also as a basic research for optical planar circuit with 2D pattern to confined the optical field laterally, simple optical circuit such as bend with large bend angle, Y branch line with large branching angle and circular bend are analyzed and experimented. Following results, still preliminary, are obtained.
(1) Multilayred thin-film slab waveguide being constructed by TiO2/SiO2,10 layrs are enough for sufficient TE-TM mode separation, which is also confirmed by calculation and experiment.
(2) Loss at this time is measured to be l. 6dB/cm for TM mode and 3dB/cm for TE mode.
(3) As for
the analysis of 3D optical waveguide, supposing the top and bottom metal boundary at the proper position, about 25 height modes of TE and TM are necessary to realize the continuity of the tangential field components.
(4) As for multilayred 3D optical wave guide, single mode operation is possible for 0.3mu thickness but multi mode operation for 0.6mu with step-type side-confinement, Rib-type side-confinement again makes this structure single mode operation.
(5) Dielectric strip loaded 3D optical waveguide with multilayred structure is analyzed theoretically.Effect of the dielectric thickness is saturaed with thickness because of exp decay of the field.
(6) Using the above structure, maximum bend angle is estimated based on geometrical optics. This result is confirmed by experiment.
(7) Rib-type multilayred 3D optical waveguide with asymmetrical structure is analyzed theoretically, where number of layrs at both side are controlled separately. Interesting results are obtaind.
(8) It is pointed out that parallel coupled optical waveguide using above structure can control the coupling strength widely. Propagation constant of the parallel coupled waveguides is calculated, which confirms the existence of strong coupling.
(9) In addition, it must be noted that field analysis of the strongly confined 3D optical waveguide discontinuity and thecorresponding experiment has beeen carried out in parallel with the research of the multilayred optical waveguide. Less