Abstract: An optical network for bi-directional communication includes: a base station for generating downlink optical signals and detecting uplink optical signals; and a remote antenna unit for transmitting the downlink optical signals and generating the uplink optical signals to the base station; wherein the remote antenna includes: an optical detector for converting the downlink optical signals into downlink radio signals; an antenna for transmitting the downlink radio signals to outside thereof, and receiving the uplink radio signals in wireless communication; a semiconductor optical amplifier for converting the uplink radio signals into the uplink optical signals to output the uplink optical signals to the base station; and a circulating device having a plurality of ports, each of which is connected to the antenna, the optical detector, and the semiconductor optical amplifier, respectively.

Abstract: A dual-port broadband light source with independently controllable output powers includes a broadband light source having a first gain medium pumped by an input pump light in order to output a first amplified spontaneous emission through both ends thereof. A second gain medium pumped by another input pump light in order to output a second amplified spontaneous emission through both ends thereof. A reflector disposed between the opposite ends of the first and second gain mediums to reflect the input first and second amplified spontaneous emissions. The first and second amplified spontaneous emissions output from the first and second gain mediums are then output to the outside through first and second output terminals.

Abstract: Disclosed are a method for broadcasting signal transmission in a wireless communication system providing a broadcasting service and a corresponding wireless communication system. In such a method and a system, a terminal receives a signal transmitted from a repeater to calculate received performance information of the signal and then transmits the received performance information to an administration center if the received performance information is equal to or greater than a reference error value. The administration center controls the repeater based on the received performance information transmitted from the terminal. The repeater adjusts transmission signal intensity or a transmission angle based on a control signal transmitted from the administration center.

Abstract: A wavelength division multiplexed passive optical network (WDM PON) includes a central office that has: a broadband light source, a first wavelength division multiplexer to spectrum-slice light outputted from the light source, semiconductor optical amplifiers or variable optical attenuators, each modulating an associated one of spectrum-sliced lights in accordance with input data, and a second wavelength division multiplexer to multiplex optical signals respectively outputted from the semiconductor optical amplifiers. A remote node, connected to the central office via a main optical fiber, distributes the optical signals to distribution optical fibers, and, in, turn, to respective optical network units.

Abstract: The present invention relates to a siloxane monomer containing a trifluorovinylether group and a sol-gel hybrid polymer prepared using the monomer, more particularly to siloxane monomer with novel structure prepared by reacting alkoxychlorosilane with a Grignard reagent containing a trifluorovinylether (—OC2F3) group, a method of preparing the same and a sol-gel hybrid polymer containing a perfluorocyclobutane (PFCB) group prepared from sol-gel reaction using said siloxane monomer containing a trifluorovinylether group.

Abstract: A dual-port broadband light source with independently controllable output powers includes a broadband light source having a first gain medium pumped by an input pump light in order to output a first amplified spontaneous emission through both ends thereof. A second gain medium pumped by another input pump light in order to output a second amplified spontaneous emission through both ends thereof. A reflector disposed between the opposite ends of the first and second gain mediums to reflect the input first and second amplified spontaneous emissions. The first and second amplified spontaneous emissions output from the first and second gain mediums are then output to the outside through first and second output terminals.

Abstract: A portable flag holding pole having a flag tube (2) a holder (1), rising and setting groove (3) to facilitate the rising and setting of a flag (5) into an inner tube (6), a cap 12, a slope gear (16) and a slope gear projection (15) positioned at the inner part of the cap (12), a projection piece (17) of the slope gear (16) for insertion into a cutting groove (7), an axial pin (18) connected to the slope gear projection (15), a revolving body (9) is flexibly mounted at an end of the winding inner tube (6) through which an insert driving shaft (10) is inwardly passed and a spring (8) is mounted flexibly, characterized in that the cutting groove (7) engages a fixed pin (19) of the revolving body (9) with the insert holding piece (11) positioned at the rear end of the insert driving shaft (10) inserted into the insert holding piece (22) of a supporting means (20).