Optical element having wavelength selectivity

#The present invention relates to an optical element having wavelength selectivity, and, more particularly, to an optical element which multiplexes lights of different wavelengths or demultiplexes multiplexed light wavelength by wavelength.

#Optical elements using an optical fiber and collimator lens have conventionally been used as optical communication equipment parts. When optical communication becomes very popular from now on, miniaturization and integration of optical communication equipment parts become further essential. Optical communication requires a technique which demultiplexes light by selectively transmitting or reflecting light wavelength by wavelength. A multilayered film filter which has high refractive-index dielectric layers and low refractive-index dielectric layers alternately laminated, e.g., an edge filter or a narrow-band filter, is known as an optical filter.

#An optical communication equipment part 100 as shown in, for example, FIG. 1 is known as a conventional optical communication equipment part which uses such an optical filter. The optical communication equipment part 100 demultiplexes mixed light signal including sixteen kinds of optical signals of the wavelengths λ1-λ16 with different center wavelengths into individual optical signals. As shown in FIG. 1, the optical communication equipment part 100 includes a plurality of collimator lenses L1 to L7, L9 to L15, L20, a plurality of optical filters (a narrow-band filter) F1 to F7, F9, F10 to F15 and an edge filter F20. An optical signal is sent among those members through an optical fiber.

#The present invention, together with objects and advantages thereof, may be better understood by reference to the following description of the typified embodiments together with the accompanying drawings.

#FIG. 1 is a schematic connection diagram of a conventional optical element.

#FIG. 2 is a schematic perspective view of an optical element according to a first embodiment of the present invention.

#(First Embodiment)

#FIG. 2 is a schematic perspective view showing the cross section of an optical element 21 according to the first embodiment of the present invention. The optical element 21 includes a light guide plate 22, a multilayered film filter 23 and an optical thin film 24 as shown in FIG. 2. The multilayered film filter 23 is formed by alternately laminating high-refractive-index dielectric layers and low-refractive-index dielectric layers on lengthwise-directional one end face 22a of the light guide plate 22.

#The light guide plate 22 is made of, for example, glass or resin, and is a transparent body having a higher refractive index than air. The light guide plate 22 is formed like a plate extending long and narrow in the right and left directions on the sheet of FIG. 2.