Optical Carrier transmission rates

About: Optical Carrier transmission rates is a research topic. Over the lifetime, 2463 publications have been published within this topic receiving 33293 citations.

Full-duplex fiber-wireless link for alternative wired and 40-GHz band wireless access based on differential quaternary phase-shift optical single sideband millimeter-wave signal

Abstract: A full-duplex fiber-wireless link with a uniform single sideband differential quaternary phase-shift keying optical millimeter-wave signal is proposed to provide wired or 40-GHz band wireless access alternatively. The uniform optical millimeter-wave signal that supports services for wired or wireless users is produced via an LiNbO3 Mach-Zehnder modulator. After being transmitted to the hybrid optical network unit (HONU), it can be demodulated in different patterns on the demand of the user terminals for wired or wireless access. Simultaneously, part of the blank optical carrier abstracted from it is reused as the uplink optical carrier, so the HONU is free from the laser source, and thus, the complexity and cost of the system are reduced. Moreover, since the two tones of the dual-tone optical millimeter wave come from the same source, they maintain high coherency even after being transmitted over fiber. Additionally, the downlink data are carried by one tone of the dual-tone optical millimeter wave, so the downlink optical millimeter-wave signal suffers little from the fiber chromatic dispersion and laser phase noise. The theoretical analysis and simulation results show that our proposed full-duplex link for alternative wired and wireless access maintains good performance even when the transmission link with standard single mode fiber is extended to 30 km.

Full-duplex radio-over-fiber (RoF) access device

Abstract: The invention discloses a full-duplex radio-over-fiber (RoF) access device. An X-axis polarization state and a Y-axis polarization state of an optical carrier are respectively modulated via optical polarization multiplexing at a central station, wherein the X-axis polarization state is used for providing a carrier for downlink intermediate-frequency data signals; and the Y-axis polarization state is used for an optically generated millimeter-wave local oscillation source and an uplink transmission signal light source for a base station. In the base station, the intermediate-frequency data signals from the central station and the millimeter-wave local oscillation source produced by the base station are transmitted to a wireless user after up-conversion, and millimeter-wave signals from the wireless user and the millimeter-wave local oscillation source produced by the base station are transmitted back to the central station after down-conversion, in combination with carrier reutilization. The functions of downlink signal transmission, generation of the millimeter-wave local oscillation source, optical carrier reutilization and uplink signal transmission are realized by one optical carrier, therefore, the full utilization of the frequency of the optical carrier is realized, no radio frequency source or light source is needed in the base station, and the cost of a full-duplex RoF access system can be reduced.

Simulation of all-optical time division multiplexed router

Abstract: To date most research on optical networking has concentrated on wavelength-division multiplexing (WDM), which routes different packets according to the wavelength of the optical carrier. Optical time-division multiplexing (OTDM) is considered as an alternative to WDM for future networks and with single stream data rates of 100 Gb/s using a single wavelength at high (up to 100 Gbit/s) data rates 1-3 . In this paper we have developed a model of an all optical router based on the terahertz optical asymmetric demultiplexer (TOAD). The model architecture is based on a system which has as its input an OTDM packet containing header and payload information. The model simulates extraction of header information from the data stream using one TOAD, which is subsequently used to make a routing decision. The payload information is routed through a second TOAD according to the information contained in the header. Simulations require the use of the TOAD in two distinct modes 1). A bit level demultiplexer for the header 2). A frame level demultiplexer for the payload. Consequently less stringent requirements are required with regard to the TOAD switch resolution for payload demultiplexing compared to header demultiplexing. However, as our simulations show the wider window allowed in case 1 introduces a higher level of residual crosstalk. In case 2 the higher resolution imposes a greater restriction on the jitter present. At this stage a simple 1 by 2 router is presented, however further work will enhance the model to a network with multiple inputs and outputs.

Multi-carrier generating device, optical transmitter and multi-carrier generating method

Abstract: The invention discloses a multicarrier generating device which comprises a first MZM, a second MZM, an electrical branching unit and a phase shifter, wherein the electrical branching unit divides a first clock driving signal into two paths to be output, and the first clock driving signal is output to the first MZM; a second clock driving signal is output to the phase shifter, the phase-shifting processing of the second clock driving signal is carried out by the phase shifter, and the second clock driving signal is output to the second MZM; the first MZM modulates an optical carrier signal under the driving of the first clock driving signal and outputs the modulated optical carrier signal to the second MZM; and the second MZM modulates the optical carrier signal output and modulated by the first MZM under the driving of the second clock driving signal processed by the phase shifter and outputs a multicarrier signal. The invention also provides the multicarrier generating device, an optical transmitter and a multicarrier generating method, which can generate different quantities and frequency intervals of carriers.

Optical channel sounder

Abstract: The present invention relates to an optical channel sounding transmitter apparatus (1001), comprising an optical signal generator (1003) for generating an optical carrier signal; an optical modulator (1005) for modulating the optical carrier signal with a predetermined training sequence to obtain an modulated optical signal; a first optical transmitter for transmitting the optical carrier signal; and a second optical transmitter for transmitting the modulated optical signal. Further the present invention relates to a coherent optical channel sounding receiver apparatus (1011), comprising a first optical receiver (1013) for receiving an optical carrier signal over a first optical channel; a second optical receiver (1013) for receiving a modulated optical signal over a second optical channel, the modulated optical signal comprising a received copy of the optical carrier signal modulated with a predetermined training sequence, the received copy of the optical carrier signal being affected by the optical channel; an optical down converter (1015) for down converting the modulated optical signal using the received optical carrier signal to obtain a down converted signal; and a channel estimator (1017) for estimating a channel characteristic of the second optical channel upon the basis of the down converted signal and the predetermined training sequence.