Abstract: A transmitter that performs stimulated Brillouin scattering suppression is provided. The transmitter includes a non-linear device having an optical input adapted to receive an optical signal, an amplitude modulation input adapted to receive an amplitude modulation signal, a phase modulation input and an output. The transmitter also includes a stimulated Brillouin scattering (SBS) oscillator/driver having first and second oscillators coupled to the phase modulation input of the non-linear device and an amplifier coupled to the output of the non-linear device. The transmitter further includes a laser coupled to the optical input of the non-linear device.

Abstract: A method and apparatus for pulse frequency modulation for analog optical communication. A train of optical pulses is generated. The spectrum of the optical pulses in the train of optical pulses can be broadened to provide a train of broad spectrum optical pulses. The broadening can be provided by self-phase modulation. Alternatively, broad spectrum optical pulses can be provided by merely having the optical pulses be less than 1 ps duration. A desired optical frequency slice from the train of spectrum broadened optical pulses is selected by a tunable Fabry-Perot filter. A desired optical frequency slice from the broad spectrum optical pulses is selected by a tunable Fabry-Perot filter. The tunable Fabry-Perot filter has a pair of Distributed Bragg Reflectors separated by an electro-refractive section.

Abstract: A transmitter formed of two or more light-emitting sections such as LEDs, which are physically arranged in a predetermined manner, is disposed in the real world object, and each light-emitting section transmits data by flashing at a flashing pattern representing the transmission data of a predetermined bit length. A receiver, on the other hand, includes a photoreceiving section formed from a two-dimensional photoreceiving surface, decodes the transmission data on the basis of the photoreceived flashing pattern, and recognizes the spatial information of an object on the basis of the flashing position on the two-dimensional photoreceiving surface. Therefore, information, such as an ID, can be obtained from the object in the real world, and also, the spatial position of the object can be recognized at the same time.

Abstract: A branch portion 101 branches an inputted electrical signal into an in-phase signal and an opposite phase signal which have an opposite relation as to a phase. A first FM laser 104 converts the in-phase signal into an optical frequency-modulated signal (a first optical signal) having a center wavelength &Dgr;1 and then outputs the resultant signal. A second FM laser 105 converts the opposite phase signal into an optical frequency-modulated signal (a second signal) having a center wavelength &Dgr;2 and then outputs the resultant signal. The two optical signals are combined and then inputted into an optical-electrical converting portion 106.

Abstract: Optical transmission being performed by frequency modulating frequency-division-multiplexed multi-channel signals as a single unit, distortion that is caused by a ripple-shaped group delay deviation in a transmitter 2, a receiver 4 and an optical link 3 is reduced by providing a level adjuster 2a for adjusting the level of frequency-division-multiplexed multi-channel signals input to the FM modulator 2b, and by increasing the input level of multi-channel signals to the FM modulator 2b by level adjusting means 2a to enlarge the bandwidth of FM signal, in the case where the number of channels is small.

Abstract: An optical frequency modulated transmitter includes a plurality of separately phased-controlled slave lasers, the outputs of which are combined to form a single output beam of the transmitter. A master optical oscillator outputs an optical signal for injection locking the plurality of slave lasers, the optical signal being frequency modulated directly in the master optical oscillator or externally thereof. Additionally, a method of frequency modulating an optical beam is disclosed using a plurality of slave lasers. Each of the slave lasers has an output, the outputs of which are combined to form the optical beam. The plurality of slave lasers is injection locked to an optical output of a master oscillator. The optical output of the master oscillator is frequency modulated before the optical output is applied to the plurality of lasers. Each slave laser of the plurality is phased controlled relative to other slave lasers of the plurality.

Abstract: An optical communications network includes a terminal which can simultaneously receive and modulate an optical signal. The terminal includes an optical modulator which is controlled by varying the bias voltage applied to it.

Abstract: The device for the homodyne reception of optical phase-keyed signals comprises a heterodyne receiver (101, 102), a data discriminator (20), a frequency acquisition circuit (80) and a local oscillator laser (70). In addition, the device has a window discriminator circuit consisting of a window comparator (30) and a feedback unit (40), whose output is connected with the input of a reversing switch (50). The window comparator (30) has been inserted between the output of the heterodyne receiver (101, 102) and the one input of the feedback unit (40), whose other input is supplied with the output signal (Si) of the discriminator (20). The output of the frequency acquisition circuit (80) is connected with the other connector of the reversing switch (50), whose output signals supplied to the control input of the local oscillator laser (70). The window comparator (30) has two or more thresholds. The feedback unit (40) can have a control input for a quadrature channel (Sq).

Abstract: In a signal transmission system made up of a transmission section, a receive section and an optical fiber installed between the transmission section and the receive section, a harmonic producing circuit and a harmonic phase shifting circuit are provided on the downstream side of an FM modulator. The harmonic producing circuit superimposes a harmonic of an FM signal on the FM signal, and the harmonic phase shifting circuit shifts the phase of the harmonic. This arrangement compensates a group delay deviation occurring in system components when an AM signal or QAM signal is modulated into an FM signal or PM signal in a modulator and then transmitted to be demodulated in a demodulator, thereby improving transmission quantity.

Abstract: To transmit a digital signal over an optical fiber link, the digital signal is modulated onto an optical carrier using frequency shift keying modulation at a modulation index of h<0.5. Under the impact of a non-linear transmission effect in the optical fiber, the use of a modulation index h<0.5 leads to an increase in maximum permitted launch power of the optical signal, increased receiver sensitivity and an increased spectral efficiency.

Abstract: An analog optical link (10) that provides high-fidelity over bandwidths greater than 1 GHz is presented. The analog optical link (10) includes a transmitter (18) having an optical modulator (20) and a receiver (16) having an optical demodulator (12). In one embodiment, the modulator (20) is a phase modulator (20) and particularly a pre-emphasis phase modulator (20) that operates as a frequency modulator at low frequencies. The demodulator (12) is a frequency demodulator (12) that includes a feed-forward function for cancelling noise.

Abstract: An angle modulating portion 1 converts an inputted electrical signal into a predetermined angle-modulated signal. An optical modulating portion 2 converts the angle-modulated signal outputted from the angle modulating portion 1 into an optical-modulated signal and sends the optical-modulated signal to an optical waveguide portion 3. An interference portion 6 separates the optical-modulated signal transmitted through the optical waveguide portion 3 into two optical signals having predetermined difference in propagation delay and then combines the optical signals. An optical/electrical converting portion 4 subjects the combined optical signal to homodyne detection, to acquire a demodulated signal of the original electrical signal and output the electrical signal.

Abstract: A branch portion 101 branches an inputted electrical signal into an in-phase signal and an opposite phase signal which have an opposite relation as to a phase. A first FM laser 104 converts the in-phase signal into an optical frequency-modulated signal (a first optical signal) having a center wavelength &lgr;1 and then outputs the resultant signal. A second FM laser 105 converts the opposite phase signal into an optical frequency-modulated signal (a second signal) having a center wavelength &lgr;2 and then outputs the resultant signal. The two optical signals are combined and then inputted into an optical-electrical converting portion 106.

Abstract: A light source with a broadband frequency-periodic output spectrum for digital spectrally coded data, whereby the light source consists of a solid state laser that is frequency-modulated or phase-modulated within one bit period.

Abstract: A wavelength converter has a phase modulated periodically modulated structure, where a nonlinear optical coefficient is periodically modulated at a fundamental period &Lgr;0 and the phase of the modulation varies nearly continuously, and the phase variation of the modulation unit structure is repeated at a period &Lgr;ph (>&Lgr;0). A conversion efficiency is made maximum when a phase mismatch amount &Dgr;&bgr; equals 2&pgr;/&Lgr;0±2&pgr;i/&Lgr;ph (i=0, 1, . . . , n, where n is a positive integer), 2&pgr;/&Lgr;0±2&pgr;(2i+1)/&Lgr;ph (i=0, 1, . . . , n), or 2&pgr;/&Lgr;0+2&pgr;i/&Lgr;f (i=m, m+1, . . . .

Abstract: Plural subcarrier-multiplexed AM signals 30 are input and narrow-band-FM-modulated by a voltage controlled oscillator 4 including the fundamental carrier wave and higher-order harmonics as the output, and the FM carrier wave component of the higher-order harmonics of the fundamental carrier wave is selectively taken out by a band-rejection filter 5, shifted to the lower frequency side by a frequency converter 7, converted into an optical signal by an electric/optic converter 3 and transmitted.

Abstract: An FM signal converter comprising: an amplitude detecting unit for detecting amplitude variation of a plurality of signals that are multiplexed with subcarriers, as an amplitude variation signal; a peak detection unit for determining from said amplitude variation signal whether a peak of the amplitude of said plurality of signals exceeds a threshold and for generating peak detection information that includes information about said peak of the amplitude; a frequency signal source for providing signal with a predetermined frequency that differs from any of the frequencies of said subcarriers; an amplitude phase control unit for adjusting amplitude and phase of the signal from the frequency signal source according to said peak detecting information and outputting the adjusted signal as a corrected signal; signal combining means for combining said corrected signal and said plurality of signals multiplexed with subcarriers, with considering a time for generating the corrected signal; and an FM modulator for

Abstract: An optical link is described for transmission of an RF signal using an optical fiber having opposing ends and configured such that unwanted distortion signals are produced when optical signals pass through the optical fiber. At least first and second optical signals are transmitted through the optical fiber, where the optical signals have been modulated with an RF signal in such a way that a predetermined relationship is produced between the RF signals modulated on the first and second optical signals. At the opposing end of the optical fiber, a receiving arrangement receives the modulated first and second optical signals including the unwanted distortion signals produced during the transmission through the optical fiber. The receiving arrangement then regenerates the RF signal from the modulated first and second optical signals while causing the unwanted distortion signals to be canceled based on the predetermined relationship between the RF signals modulated on the first and second optical signals.

Abstract: Light emitting diode (LED) bar systems have large surface areas and extensive cabling that carry high frequency clocks and data. As the process speeds increase, the higher clock and data rates become an electromagnetic interference (EMI) problem. As the U.S. federal government restricts EMI emissions, many have turned to shielding techniques. However, a spread spectrum technique now may also reduce peak EMI amplitudes by distributing the EMI energy over a range of frequencies. The pixel data may be clocked into a LED bar system with a varying frequency to spread the energy over the range of the modulation. The same total energy is still emitted from the system, but the peak energy at any particular frequency is reduced.