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.

Method and apparatus of utilizing RF/microwave and optical mixing techniques to select a given band of an optical transmission

Abstract: A method and apparatus (10) are provided for transmitting (12, 14) and receiving (24, 26) multiple RF/microwave subcarriers on a single optical wavelength over an optical link. The method includes the steps of modulating a plurality of RF/microwave subcarrier frequencies with a respective communication signal and modulating an optical carrier wave with the plurality of modulated RF/microwave subcarrier frequencies. The method further includes the steps of detecting the plurality of RF/microwave subcarriers of the optical carrier wave and mixing (102) those subcarriers with a first local oscillator (LO) frequency to create a new heterodyne IF frequency above the highest frequency component of the modulated signal spectrum of the detected subcarriers, filtering an RF/microwave subcarrier frequency of the plurality of detected RF/microwave subcarriers utilizing a bandpass filter (106) at an IF center frequency of the new IF frequency and mixing the filtered RF/microwave subcarrier with a second local oscillator (LO) (108) frequency to derive a difference frequency at a desired center frequency for propagation over the subsequent network element.

Optical Comb Sources for High Dynamic-Range Single-Span Long-Haul Analog Optical Links

Abstract: We present a new technique for achieving high spurious-free dynamic range in long-haul analog optical links. Our technique utilizes an optical comb as the optical carrier in an externally intensity-modulated direct-detection link architecture. By distributing the optical carrier power over the comb (in contrast to concentrating it in a single continuous-wave laser, as in a conventional link), this technique circumvents the optical power limitations imposed by stimulated Brillouin scattering allowing a substantial increase in optical launch power. Increased launch power translates directly to decreased optical amplification requirements at the link terminus and results in a significantly lower noise floor than may be achieved in a conventional link architecture. To our knowledge, the dynamic range of SFDR=105.5 dB (1-Hz bandwidth, L=50 km link) is the highest reported to date for a single-span long-haul analog optical link.

High Resolution Frequency Standard Dissemination via Optical Fibre Metropolitan Network

Abstract: We present in this paper results on a new dissemination system of ultra-stable reference signal at 100 MHz on a standard fibre network. The 100 MHz signal is simply transferred by amplitude modulation of an optical carrier. Two different approaches for compensating the noise introduced by the link have been implemented. The limits of the two systems are analyzed and several solution suggested in order to improve the frequency stability and to further extend the distribution distance. Nevertheless, our system is a good tool for the best cold atom fountains comparison between laboratories, up to 100 km, with a relative frequency resolution of 10-14 at one second integration time and 10-17 for one day of measurement. The distribution system may be upgraded to fulfill the stringent distribution requirements for the future optical clocks.

A True Time Delay Beamforming System Incorporating a Wavelength Tunable Optical Phase-Lock Loop

Abstract: A true time delay (TTD) beamforming system incorporating a wavelength tunable optical phase-lock loop (OPLL) module is proposed and experimentally demonstrated. In the proposed system, instead of using a high-frequency intensity modulator to modulate the optical carrier with an RF signal, we use two laser diodes (LDs) that are phase locked to generate an RF signal, which is then sent to a fiber Bragg grating (FBG) prism to produce different time delays. Since no optical intensity modulator is used, the system can operate at much higher frequencies with a reduced cost. In addition, the use of only two wavelengths eliminates the power-penalty problem caused by chromatic dispersion. In the proposed approach, the wavelengths from the two LDs are phase-locked using a frequency-discriminator-aided OPLL. A TTD beamforming system, using the OPLL in combination with an FBG prism to achieve tunable time delays, is investigated. Experimental time-delay results are provided.

Optical upconversion techniques for high-sensitivity millimetre-wave detection

Abstract: Millimeter-wave radiation has the unique ability to penetrate atmospheric obscurations such as smoke, fog, and light rain while maintaining the capability for high-resolution imaging. However, suitable technologies for creating high-sensitivity, large pixel-count detectors are a limiting factor in the implementation of such systems. To this end, we present a technique for detecting millimeter-wave radiation based on optical upconversion that promises both high sensitivity and scalability to large pixel arrays. High-speed optical modulation is used to transfer millimeter-wave radiation onto the sidebands of a near-infrared optical carrier frequency. Optical filtering techniques are subsequently used to suppress light at the carrier frequency. The resultant signal is passed to a low-frequency photodetector, which converts the remaining sideband energy to a photocurrent proportional to the incident millimeter wave energy at the modulator input. Utilizing the low noise powers of such photodetectors, high sensitivities may be obtained even accounting for the relatively high signal losses associated with optical upconversion. Since optical upconversion inherently preserves both phase and amplitude information and fiber optics may readily be used for low-loss routing of the modulated signal, such an approach offers promise for high-resolution synthetic aperture imaging. Alternatively, since each of the required components may be fabricated in III-V materials using planar semiconductor processing techniques, integration of multi-pixel arrays is feasible. Herein, we present experimental results obtained using a baseline detector assembled from commercially available fiber-optic components as well as efforts to integrate the desired functionality into a single GaAs substrate. An initial noise equivalent power (NEP) of the proposed detector has been demonstrated at sub-nanowatt levels, with improvements to sub-picowatt NEP's anticipated as the setup is optimized.