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.

Counting the cycles of light using a self-referenced optical microresonator

Abstract: Phase coherently linking optical-to-radio frequencies with femtosecond mode-locked laser frequency combs has enabled counting the cycles of light and is the basis of optical clocks, absolute frequency synthesis, tests of fundamental physics, and improved spectroscopy. Using an optical microresonator frequency comb to establish a coherent link between optical and microwave frequencies will extend optical frequency synthesis and measurements to areas requiring compact form factor, on-chip integration, and comb line spacing in the microwave regime, including coherent telecommunications, astrophysical spectrometer calibration, or microwave photonics. Here we demonstrate a microwave-to-optical link with a microresonator. By using a temporal dissipative single soliton state in an ultrahigh-Q crystalline microresonator that is broadened in highly nonlinear fiber, an optical frequency comb is generated that is self-referenced, allowing us to phase coherently link a 190 THz optical carrier directly to a 14 GHz microwave frequency. Our work demonstrates that precision optical frequency measurements can be realized with compact high-Q microresonators.

Tunable sharp and highly selective microwave-photonic band-pass filters based on stimulated Brillouin scattering

Abstract: Stimulated Brillouin scattering (SBS) in optical fibers has long been used in frequency-selective optical signal processing, including in the realization of microwave-photonic (MWP) filters. In this work, we report a significant enhancement in the selectivity of SBS-based MWP filters. Filters having a single passband of 250 MHz–1 GHz bandwidth are demonstrated, with selectivity of up to 44 dB. The selectivity of the filters is better than that of the corresponding previous arrangements by about 15 dB. The shape factor of the filters, defined as the ratio between their −20 dB bandwidth and their −3 dB bandwidth, is between 1.35 and 1.5. The central transmission frequency, bandwidth, and spectral shape of the passband are all independently adjusted. Performance enhancement is based on two advances, compared with previous demonstrations of tunable SBS-based MWP filters: (a) the polarization attributes of SBS in standard, weakly birefringent fibers are used to discriminate between in-band and out-of-band components and (b) a sharp and uniform power spectral density of the SBS pump waves is synthesized through external modulation of an optical carrier by broadband, frequency-swept waveforms. The signal-to-noise ratio of filtered radio-frequency waveforms and the linear dynamic range of the filters are estimated analytically and quantified experimentally. Lastly, a figure of merit for the performance of the filters is proposed and discussed. The filters are applicable to radio-over-fiber transmission systems.

Pilot-Symbols-Aided Carrier-Phase Recovery for 100-G PM-QPSK Digital Coherent Receivers

Abstract: A feedforward pilot-symbols-aided carrier-phase recovery scheme is described. The approach relies on pilot symbols that are time-division multiplexed with the transmitted data. In the scheme, an initial coarse estimation of the optical carrier phase, exploiting the knowledge of pilot symbols, is followed by a fine nondata-aided, or blind, estimation. The main advantage of the proposed solution is that of avoiding the phase- ambiguity problem after a cycle slip. The overhead and the impact on the performance of pilot symbols are investigated for long-haul transmission of 100-Gb/s polarization-multiplexed quadrature phase-shift keying wavelength-division-multiplexing signals in different scenarios. For homogeneous transmission, the proposed scheme outperforms blind carrier recovery with differential decoding.

High-performance microwave transversal filter using fiber Bragg grating arrays

Abstract: Measured results from a microwave photonic traversal filter exploiting fiber Bragg grating (FBG) arrays and achieving a high-performance tunable bandpass microwave response are presented. Tuning is affected by changing the optical carrier wavelength to select the operating gratings, and the high-quality frequency response is obtained by weighting the reflections of the gratings. This experiment demonstrates that sophisticated passive signal processing functionality can be achieved practically using FBGs.

A coherent optically controlled phased array antenna system

Abstract: A true-time delay, optically controlled phased array antenna system whereby a large number (100-2500) of antenna elements can receive a series of microwave delays via use of a coherent optical carrier signal is described. Both transmit and receive antenna arrays are described, and the signal-to-noise ratio for a 128 channel system is calculated to be approximately 40 dB with an optical link loss of only approximately 3 dB for a 1 GHz instantaneous bandwidth at a wavelength of lambda 1.55 mu m. It is shown that the use of coherent optically controlled phased array antennas provides improved controllability and immunity from noise and system losses over other architectures currently being investigated. >