A method for allocating bandwidth to a first ONU, a second ONU, M.sub.1 ONUs, and M.sub.2 ONUs includes, during an allocation cycle, (i) granting a respective upstream time slot to, of a plurality of N ONUs, only each of the M.sub.1 ONUs, and (ii) granting a first upstream time slot to the first ONU. Each of the M.sub.1 ONUs and M.sub.2 ONUs is one of the plurality of N ONUs. The method also includes, during a subsequent cycle, (i) granting a respective upstream time slot to, of the plurality of N ONUs, only each of the M.sub.2 ONUs. The N ONUs includes a skipped-ONU that is one of either, and not both, the M.sub.1 ONUs and the M.sub.2 ONUs. The method includes, during the subsequent allocation cycle, granting a second upstream time slot to a second ONU, which is not one of the plurality of N ONUs.

An optical transmitter that outputs an optical signal with a pulse amplitude modulation (PAM) configuration is disclosed. The optical transmitter includes a light-generating device and a driver. The light-generating device has non-linearity in a transfer characteristic between the electrical driving signal and the optical signal. The driver includes a PAM signal generator, a level controller, and an output driver. The PAM signal generator receives the input electrical signal and outputs a PAM signal. The level controller adjusts the electrical levels of the PAM signal based on the non-linear transfer characteristic of the light-generating device, where the electrical levels set the optical levels of the optical signal with preset ratios. The output driver generates the driving signal by superposing the electrical levels adjusted by the level controller with the PAM signal provided from the PAM signal generator.

A single photons communication method and system is provided. In an example, an information loading module in a transmitting terminal of the single photons communication system may code to-be-sent target information as a corresponding target modulation frequency according to a pre-saved relationship between information and modulation frequency, and perform frequency modulation on a quantum state of communication light generated by a light source by using the target modulation frequency so that the transmitting terminal may send out modulated target communication light. After receiving the target communication light, an information decoding module in a receiving terminal of the single photons communication system may decode the target modulation frequency from a sequence of receiving photons of the target communication light through Fourier transform or other ways, and obtain target information corresponding to the target modulation frequency according to the relationship between information and modulation frequency.

A method, system, and apparatus enabled to selectively choose a baud rate for communication of optical data using a modem enabled to operate with an optical signal modulated at plurality of finely tuned baud rates.

An apparatus for signal modulation in a point-to-multipoint optical network is configured to modulate a single-wavelength carrier wave before distribution towards optical receivers of a first type adapted for intensity detection and a second type adapted for optical field detection. The apparatus includes a first module configured to modulate the carrier wave by varying the intensity of the carrier wave to represent data intended for the first type of receivers, and by controlling the phase and/or polarization of the carrier wave during selected periods. The apparatus includes a second module configured to modulate the carrier wave by varying the phase and/or polarization of the carrier wave to represent data intended for the second type of receivers, and by varying the intensity of the carrier wave during selected periods.

A multi-speed transceiver device includes a chassis having an optical cable connector coupled to a transceiver processor, and an optical waveguide coupling. A data receiving subsystem in the chassis couples the transceiver processor to the optical waveguide coupling, includes data receiving optical waveguides, and transmits first data received from the transceiver processor to the optical waveguide coupling over a number of the data receiving optical waveguides that depends on a first data transmission speed at which the first data was received. A data transmission subsystem in the chassis couples the transceiver processor to the optical waveguide coupling, includes data transmission optical waveguides, and receives second data via the optical waveguide coupling and over a number of the data transmission optical waveguides that depends on a second data transmission speed at which the second data was received, and then transmits that second data to the transceiver processor.

A scheme for generating asymmetric single sideband photonic vector signal at millimeter wave spectral region is described. At a transmitter, information bits to be transmitted are modulated using a vector modulation technique to generate a baseband signal. The baseband signal is converted into its single sideband (SSB) version using a complex frequency source having a first frequency. The real part of the upconverted signal is added to the real part of a second frequency source and is input as I component to an I/Q modulator. The imaginary part of the upconverted signal is added to the imaginary part of the second frequency source and is used as the Q component. The I/Q modulator is driven by a laser source at frequency fc. The resulting signal is transmitter over an optical transmission medium and upconverted by a single-ended photodiode to a desired radio-frequency (RF) carrier frequency.

The invention relates to a method for creating a control channel in an optical transmission signal, wherein the optical transmission signal (S.sub.DS,i, S.sub.US,i) includes an optical carrier frequency component, a higher frequency modulation component carrying user information to be transported from a first end to a second end of an optical transmission link and a lower frequency modulation component carrying control information, the higher frequency modulation component realizing a user channel and the lower frequency modulation component realizing the control channel, and wherein the lower frequency modulation component is created by amplitude modulation. According to the invention, the lower frequency modulation component includes a binary digital pilot tone signal component which corresponds to a pilot tone signal having a predetermined pilot tone frequency (f.sub.i).

A first resistor connected in parallel to a semiconductor optical modulator having first ends, the first resistor and first ends connected to a reference potential. A first end of a first transmission line is connected to second ends of the semiconductor optical modulator and the first resistor. A second transmission line is connected in series to the first transmission line and has an impedance lower than that of the first resistor. A first end of the second transmission line is connected to a second end of the first transmission line. A third transmission line is connected in series to the first and second transmission lines and has an end connected to a second end of the second transmission line, and has an impedance equal to that of the first transmission line. A second resistor and a capacitor are connected in series between the third transmission line and the reference potential.

A system and method for transmitting a wavelength division multiplexed (WDM) signal on an optical transmission path. The system includes at least one first modulation format transmitter configured to generate an associated first modulation format signal on an associated signal wavelength using a first modulation format having a first spectral efficiency, and at least one second modulation format transmitter configured to generate an associated second modulation format signal on an associated signal wavelength using a second modulation format having a second spectral efficiency higher than the first spectral efficiency. The second modulation format signals having an optical power set nominally higher than the optical power of the first modulation format signals. The first and second modulation format signals are combined into an aggregate output signal on the optical transmission path.