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.

High-Q Microsphere Cavity for Laser Stabilization and Optoelectronic Microwave Oscillator

Abstract: With submillimeter size and optical Q up to approximately 10 (exp 10), microspheres with whispering-gallery (WG) modes are attractive new component for fiber-optics/photonics applications and a potential core in ultra-compact high-spectral-purity optical and microwave oscillators. In addition to earlier demonstrated optical locking of diode laser to WG mode in a microsphere, we report on microsphere application in the microwave optoelectronic oscillator, OEO. In OEO, a steady-state microwave modulation of optical carrier is obtained in a closed loop including electro-optical modulator, fiber-optic delay, detector and microwave amplifier. OEO demonstrates exceptionally low phase noise (-140 dBc/Hz at l0kHz from approximately 10GHz carrier) with a fiber length approximately 2km. Current technology allows to put all parts of the OEO, except the fiber, on the same chip. Microspheres, with their demonstrated Q equivalent to a kilometer fiber storage, can replace fiber delays in a truly integrated device. We have obtained microwave oscillation in microsphere-based OEO at 5 to 18 GHz, with 1310nm and 1550nm optical carrier, in two configurations: 1) with external DFB pump laser, and 2) with a ring laser including microsphere and a fiber optic amplifier. Also reported is a simple and efficient fiber coupler for microspheres facilitating their integration with existing fiber optics devices.

A 0.18 /spl mu/m SiGe BiCMOS receiver and transmitter chipset for SONET OC-768 transmission systems

Abstract: A 43-Gb/s receiver (Rx) and transmitter (Tx) chip set for SONET OC-768 transmission systems is reported. Both ICs are implemented in a 0.18-/spl mu/m SiGe BiCMOS technology featuring 120-GHz f/sub T/ and 100 GHz f/sub max/. The Rx includes a limiting amplifier, a half-rate clock and data recovery unit, a 1:4 demultiplexer, a frequency acquisition aid, and a frequency lock detector. Input sensitivity for a bit-error rate less than 10/sup -9/ is 40 mV and jitter generation better than 230 fs rms. The IC dissipates 2.4 W from a -3.6-V supply voltage. The Tx integrates a half-rate clock multiplier unit with a 4:1 multiplexer. Measured clock jitter generation is better than 170 fs rms. The IC consumes 2.3 W from a -3.6-V supply voltage.

Methods for crosstalk measurement and reduction in dense WDM systems

Abstract: We propose a scheme for the monitoring and reduction of crosstalk arising from the limited stop-band rejection of optical bandpass filters in dense WDM systems. The optical carrier at each wavelength is modulated with a subcarrier tone unique to that wavelength. The level of crosstalk from a given channel can be determined by measuring the power of the corresponding tone. Crosstalk from other channels can be cancelled in a linear fashion by weighting and summing the photocurrents of the desired channel and several adjacent interfering channels. Alternatively, in nonlinear crosstalk cancellation, decisions are made on the interfering signals, and these decision are weighted and summed with the photocurrent of the desired channel. For example, assuming an optical filter having a Gaussian passband, the channel density can be increased from 20 to 30%, depending on the number of adjacent channels detected. The signal-to-interference ratio can be increased by 10-20 dB and the system can achieve a BER<10/sup -9/ under conditions where, without interference cancellation, the signal-to-interference ratio would be less then 10 dB.

Bidirectional Optical Amplification in Long-Distance Two-Way Fiber-Optic Time and Frequency Transfer Systems

Abstract: In this paper, the transmission of the time and/or frequency signals (e.g., 1 pulse per second and 10 MHz) coded on the optical carrier by means of an on-off intensity modulation in the two-way fiber-optic link is considered. It is assumed that the bidirectional optical amplification in the single piece of an erbium-doped fiber is exploited to compensate the attenuation of the optical path. Such configuration of the amplifiers, offering the highest possible symmetry of the propagation conditions in both directions, is well suited for the two-way transfer method exploiting the symmetry of the link. We proposed the method of estimating interfering signals and jitter, which appear at both sides of such bidirectional fiber link because of Rayleigh backscattering and amplified spontaneous emission. This method is further exploited for finding the gains of bidirectional amplifiers, allowing optimization of the performance of the link. The experiments done with 120- and 220-km-long links, incorporating one and three amplifiers, respectively, confirmed theoretical predictions and proved that the single-path bidirectional amplifiers without any components separating the directions are useful for time or RF frequency transfer. During the experiments, both field-deployed telecommunication cables and the fibers spooled in the laboratory were used. Presented methods of analysis and optimization are useful for designing and evaluating the fiber-optic links incorporating single-path bidirectional fiber-optic amplifiers and exploiting intensity modulation for time and/or frequency transfer.

Optical upconverter apparatuses, methods and systems

Abstract: Apparatuses, methods, and systems are disclosed that provide for simultaneously upconverting electrical signals carrying information at electric frequencies onto optical subcarrier lightwave frequencies that are greater and less than the carrier frequency of the lightwave onto which the electrical frequencies were upconverted. The upconversion of the electrical signals can be performed with or without suppression of the optical carrier frequency.