Abstract: A free space optical bus system and method are provided for connecting two units of circuitry across a free space gap. A first unit of circuitry includes a multiplexer that combines a plurality of bus signals to obtain an electronic combined signal and a laser that is driven by the electronic combined signal to transmit an optical signal. A second unit of circuitry is separated from the first unit of circuitry by a free space gap. The second unit of circuitry includes a photodetector that receives the optical signal and transforms it into an electronic composite signal and a demultiplexer that divides the composite signal into a plurality of constituent signals.

Abstract: An optical receiving device capable of outputting a control signal and a data signal received as an optical signal, even if a received optical power of an optical signal inputted via an optical fiber fluctuates. An optical-to-electrical conversion section converts the optical signal inputted via the optical fiber to an electrical signal. A received optical power detection section detects a received optical power of the optical signal. A detection level setting section outputs a first detection level value or a second detection level value as a detection level. A comparison section compares the received optical power with the detection level. An output/stop switching section outputs an electrical signal as an output signal when the received optical power is greater than the detection level, and stops outputting the signal when the received optical power Pt is smaller than the detection level Lt.

Abstract: An object of the invention is to provide a control apparatus and a control method having a simple constitution, which can stably perform switching of optical path in an optical signal exchanger, while suppressing an influence on a control due to the mechanical resonance of tilt mirrors. To this end, the control apparatus of the optical signal exchanger is constituted such that in an optical signal exchanger of three-dimensional type using one set of MEMS mirror arrays, each having a plurality of tilt mirrors arranged on a plane, each tilt mirror having a reflecting surface an angle of which is controllable, when the angle of the MEMS mirror on the optical path is feedback controlled by detecting power of an optical signal output from a specific position, a resonance component removing section that removes a resonance frequency component included in a control signal is shared corresponding to a pair of driving electrodes arranged in a coaxial direction of the MEMS mirror.

Abstract: A preamplifier circuit, a clock switching circuit, and an optical receiver are provided that include a preamplifier that controls a bandwidth for conducting amplification on an input signal by varying a feedback resistance according to a control signal; a control signal generating part that determines the band of the output signal of the preamplifier to generate the control signal; and a correction signal generating part that generates a correction signal for correcting the control signal; wherein the correction signal corrects the control signal to adjust the feedback resistance. Accordingly, even when the number of rises and falls of an optical input signal in a given time period is less than a predetermined number range, the control signal may be properly generated to successfully conduct band control.

Abstract: An optical code division multiple access transmission and reception system is presented. The transmission system comprises an optical comb generator for producing multiple discrete optical signal components comprising a plurality of equally spaced wavelength components. A serial-to-parallel converter is connected with the optical comb generator for receiving receiving the serial signal components and for converting a selected group of the serial signal components into parallel signal components. An optical free-space code mask is connected with the serial-to-parallel converter for receiving the parallel signal components and for selecting two separate groups of optical signal components to generate two subsets of signal components, each for representing an associated binary data value from a data stream. The transmission system may comprise further components to enable transmission via fiber optic cable or into free-space via an antenna.

Abstract: Provided is an optical Code Division Multiple Access (CDMA) transmitting apparatus and method for transmitting bipolar data in an optical CDMA system. The optical CDMA transmitting apparatus and method of the present research has a simple structure, including only one optical CDMA encoder and one optical modulator. This technology minimizes multiple access interference by using modified pseudo-noise code in the encoding process, thus improving the optical CDMA transmission performance. The optical CDMA transmitting apparatus includes: an optical CDMA encoding means for encoding lights from the outside into a code or a complement code of the code; and an optical modulation means for transmitting the code or the complement code of the code which is selected in the optical CDMA encoding means based on the polarity (either ‘0’ or ‘1’) of the data inputted from the outside.

Abstract: A method and system enables measurement of polarization dependent loss (PDL) in an optical communications system including a plurality of cascaded optical components. An optical signal having a predetermined initial polarization state is launched into the optical communications system. A polarization state of the signal is detected at a selected detection point downstream of the launch point. The PDE is evaluated using the predetermined initial polarization state and the detected polarization state.