Abstract: The present invention has been achieved to provide a novel optical transmission system realizing high-speed optical transmission over greater distance by suppressing waveform degradation caused by mode dispersion and mode transition in a multimode optical transmission line. The optical transmission system of the present invention includes: an optical transmitter for transmitting incoherent light; an excitation mechanism for exciting a predetermined mode in the incoherent light transmitted from the optical transmitter; a multimode optical transmission line for transmitting the incoherent light transmitted from the excitation mechanism; a transmission mechanism for transmitting a predetermined mode in the incoherent light transmitted from the excitation mechanism; and an optical receiver for receiving the incoherent light transmitted from the transmission mechanism or the incoherent light transmitted from the transmission mechanism.

Abstract: A single-to-multi mode converter and an optical code division multiple access system using the same. The mode converter includes first, second, and third optical waveguides. The first optical waveguide is formed of a single-mode optical fiber and outputs a single-mode optical signal. The second optical waveguide converts the single-mode optical signal output from the first optical waveguide to a multi-mode optical signal and allows the optical power of the single-mode optical signal to be coupled to each mode of the multi-mode optical signal. The third optical waveguide is formed of a multi-mode optical fiber and transmits the multi-mode optical signal output from the second optical waveguide.

Abstract: A multimode fiber system includes a transmitter for transmitting an optical signal and a receiver that receives the optical signal. At least one mode filter is coupled between the receiver and the transmitter and passes only a specific set of fiber modes from the transmitter to be received by the receiver. The at least one mode filter comprises a tapered core section that includes a double taper configuration joined at the narrowest regions and in which each end of the two tapers has dimensions compatible with the fiber at that end.

Abstract: An optical transmitter for an optical fiber transmission system is described. The optical transmitter includes an optical source that generates an optical signal having a wavelength at an output. An optical intensity modulator modulates the optical signal with an electrical modulation signal to generate a modulated optical signal at an output. At least one parameter of the optical intensity modulator is chosen to suppress at least one of phase and sideband information in the modulated optical signal. An optical fiber is coupled to the output of the optical intensity modulator. The suppression of the at least one of the phase and the sideband information in the modulated optical signal increases an effective modal bandwidth of the optical fiber.

Abstract: A multi-mode optical fiber link is described. The multi-mode optical fiber link includes a first spatial mode converter that is coupled to a first single mode optical fiber. The first spatial mode converter conditions a modal profile of an optical signal propagating from the single mode optical fiber to the first spatial mode converter. A multi-mode optical fiber is coupled to the first spatial mode converter. A second spatial mode converter is coupled to an output of the multi-mode optical fiber and to a second single mode optical fiber. The second spatial mode converter reduces a number of optical modes in the optical signal. Both the first and the second spatial mode converters increase an effective modal bandwidth of the optical signal.

Abstract: An optical demultiplexer having at least one Bragg diffraction grating for minimizing crosstalk on the sides of transmitting and receiving optical signals, as well as an optical communication module using the optical demultiplexer. The optical demultiplexer has first and second waveguides arranged adjacent each other in a predetermined section in order to perform mode coupling, so that the optical signals input through one end of the first waveguide are transmitted to a light receiving element through the second waveguide, and in which output light waves inputted through the other end of the first waveguide are output through the one end of the first waveguide. A first Bragg diffraction grating is formed on the second waveguide and haa wavelength selectivity, for minimizing crosstalk by transmitting a reception wavelength of the optical signals at about 100% and by reflecting a wavelength of the output light waves at about 100%.

Abstract: A configuration for detecting optical signals of at least one optical channel of a planar optical circuit. At least one deflection device is provided, which couples the optical signals of at least one optical channel at least partly out of the plane of the circuit, and one detection unit is provided, which detects the signals that are coupled out outside the plane of the circuit. Therefore, a simple metrological monitoring of the signals of the optical channels of a planar optical circuit occurs with only slight signal losses and without undesirable crosstalk.

Abstract: A transmission configuration includes a transmitter for emitting radiation and a multimode optical conductor. The transmitter has a structured laser emitting radiation elements with coupled phases upon stimulation. The structured laser includes at least one structure causing the radiation elements to produce a predetermined higher-order oscillation state. The multimode optical conductor is used for passing on the radiation elements emitted from the transmitter. The radiation elements entering said multimode optical conductor together.

Abstract: The inventive beam forming technique enables use of multimode optical fibers to couple a modulated optical beam from a radiation source to an optical emitting antenna, for free-space communications. The disclosure teaches a methodology for determining the angular and frequency spectrum parameters of the optical energy applied to the fiber as well as the parameters of the fiber so as to smooth speckle-pattern caused by multimode interference and to provide a speckle-pattern contrast at or below a maximum value at which free-space communication is most efficient.

Abstract: A wiring pattern of a circuit board comprises two reference voltage lines holding a signal line therebetween, whereas the reference voltage lines on both ends are electrically connected to a conductive bracket. The bracket covers and electrically shields lead pins connecting a light-receiving device unit or light-emitting device unit to the circuit board.

Abstract: A process for fabricating a microelectromechanical optical component from a silicon substrate is disclosed. The component comprises optical propagation guides; a wall which can move with respect to the propagation guides; and an electrostatic actuator associated with return means formed by at least one beam capable of causing the moving wall to move with respect to the rest of the substrate. The substrate is single-crystal silicon having (111) crystallographic planes parallel to the plane of the substrate. The process comprises a first series of deep reactive ion etching steps during which the heights of the moving wall, of the electrodes of the actuator, and of the beams of the return means of the actuator are defined with different values, and a second wet etching step, making it possible to free the moving wall, the electrodes and the beams from the rest of the substrate.

Abstract: A system is provided to obtain loss optimized output optical power by way of feedback control and stabilization in an optical signal switching or routing system. The optical signal switching or routing system includes at least two input optical fibers and at least two output optical fibers, a controllable mechanism for directing an optical beam from one of the input optical fibers to one of the output optical fibers, and a mechanism for measuring the optical power applied to output optical fiber. The measuring mechanism provides a measure of the output optical power through a signal processing apparatus to a control apparatus. Possible other inputs to the signal processing apparatus include the input optical power, test optical power, etc. The inputs to the signal processing apparatus are compared and the signal processing apparatus outputs a signal to the control apparatus to provide optimized output power.

Abstract: A method and apparatus is provided for connecting an optical source to a multimode optical fibre in a multimode optical fibre communications system. A single mode fibre length is provided such that optical radiation admitted from an optical source at one end of the single mode fibre length is provided to a multimode optical fibre at the other end of the single mode fibre length. This method and apparatus is used in a duplex patchcord for connecting an optical transceiver to a pair of installed multimode fibres. The second fibre in the patchcord is a multimode fibre for passing optical signals to the optical receiver of the transceiver.

Abstract: A passive remote loop-back method and apparatus for optical circuit verification is described. The apparatus may be remotely controlled through either of a dial-up or a data connection. The apparatus is adapted to: perform loop-back of received optical signals; verify status on loss of carrier; and, verify the status of its dual power supplies. The apparatus is also adapted to report alarm conditions by dialing a predetermined telephone number. The advantage is a versatile apparatus that may be monitored by a remote manager, and which automatically reports alarms using a dependable alternate communications medium.