All-optical Delay Line Research Articles

Tunability Dependence of All-Optical Liquid Crystal Delay Line on Laser Polarization and Incidence Angle

This work experimentally investigates the optical manipulation of trans-cis swaps and resultantly their optical/electromagnetic imprints as a driver for realizing the tunable delay lines in the microwave X band (8-12 GHz) regime utilizing the polarization and incident angle dependencies of azo-admixed liquid crystals (LCs). Measurement results confirm that the tuning efficacy of the azo-LCs-based delay line is highly dependent on the polarization of the laser beam concerning the rubbing and filling directions of LCs. When the laser light beam is polarized parallel to the rubbed direction as well as the LCs filling direction, the achievable differential phase shift is maximized. Full Text: PDF References T. Sakamoto, Optoelectronic Circuits for Control of Lightwaves and Microwaves (London, IntechOpen 2011). CrossRef J.F. Li, "All-optically controlled microwave analog phase shifter with insertion losses balancing", Eng. Lett. 28, 3 (2020). DirectLink J.P.F. Lagerwall, G. Scalia, "A new era for liquid crystal research: Applications of liquid crystals in soft matter nano-, bio- and microtechnology", Curr. Appl. Phys. 12, 6 (2012). CrossRef S. Kim, K. Seiji, "Photochemical On–Off Switching of One-Dimensional Photonic Crystals Consisting of Azo-Functionalized Liquid Crystal Polymer and Polyvinyl Alcohol", Crystals 9, 12 (2019). CrossRef J.F. Li, "Micro-LED Mass Transfer Technologies", ICEPT (Guangzhou, IEEE 2020). CrossRef U. Chodorow, J. Parka, O. Chojnowska, "Liquid Crystal Materials in THz Technologies", Phot. Lett. Poland 4, 3 (2012). CrossRef

Demonstration of an all-optical feed-forward delay line buffer using the quadratic Stark effect and two-photon absorption in an SOA.

We have inserted into an unbiased semiconductor optical amplifier (SOA) a powerful control beam, with photon energy slightly smaller than that of the band-gap of its active region, for exciting two-photon absorption and the quadratic Stark effect. For the available SOA, we estimated these phenomena generated a nonlinear absorption coefficient β=-865 cm/GW and induced an appreciable birefringence inside the amplifier waveguide, which significantly modified the polarization-state of a probe beam. Based on these effects, we have experimentally demonstrated the operation of an all-optical buffer, using an 80 Gb/s optical pulse comb, as well as an unbiased SOA, which was therefore, devoid of amplified spontaneous emission and pattern effects.

All-optical tunable delay line based on nonlinearities in a chalcogenide microfiber coil resonator

We propose an all-optical tunable delay line based on nonlinear effects in a two-turn chalcogenide microfiber coil resonator (MCR). Continuous rotation of light due to coupling between the two uniform MCR turns at the resonance induces a time delay. Using numerical simulation, we show the possibility of designing a continuously tunable all-optical and real-time delay line, taking advantage of the high Kerr nonlinear effect in a chalcogenide glass-based MCR. The threshold power for making the Kerr nonlinearity in the chalcogenide sulfide glass (Ge20Ga5Sb10S65, also known as 2S2G) MCR is less than 0.1 W. By selecting an appropriate pump power, one can adjust the time delay in the proposed MCR delay line as desired. Results of numerical simulations show that the time delay in an appropriately designed two-turn MCR can be tuned in the range of 24–147 ps with a bandwidth of ∼4.1 GHz. Pulse broadening and distortion related to group velocity dispersion (GVD) and the self-phase modulation (SPM) effect of the proposed microfiber coil delay line (MCDL) are also studied.

∝型平坦展宽频谱可调全光时延线

∝型平坦展宽频谱可调全光时延线

All-optical tunable delay-line memory based on a semiconductor cavity-soliton laser

Cavity soliton lasers in a vertical-cavity surface-emitting laser with a saturable absorber can spontaneously move provided that a proper ratio of the carrier lifetimes in the amplifier and in the absorber is considered. Use is made of this fact to propose a scheme based on which a tunable all-optical delay line can be demonstrated. This easy-to-realize delay device exhibits high delay range, a very good delay resolution, and a wide extent of available data bandwidth. Also it is shown that the ratio of delay time to pulse duration (fractional delay) can be as large as 2300.

Coherent correlator and equalizer using a reconfigurable all-optical tapped delay line

We experimentally demonstrate a reconfigurable optical tapped delay line in conjunction with coherent detection to search multiple patterns among quadrature phase shift keying (QPSK) symbols in 20 Gbaud data channel and also to equalize 20 and 31 Gbaud QPSK, 20 Gbaud 8 phase shift keying (PSK), and 16 QAM signals. Multiple patterns are searched successfully on QPSK signals, and correlation peaks are obtained at the matched patterns. QPSK, 8 PSK, and 16 QAM signals are also successfully recovered after 25 km of SMF-28 with average EVMs of 8.3%, 8.9%, and 7.8%. A penalty of <1 dB optical signal to noise penalty is achieved for a 20 Gbaud QPSK signal distorted by up to 400 ps/nm dispersion.

Systematic design study of an all-optical delay line based on Brillouin scattering enhancedcascade coupled ring resonators

We present a technique to improve the slow-light performance of a side-coupled integratedspaced sequence of resonators (SCISSOR) combined with a stimulated Brillouin scattering (SBS)gain medium in optical fibers. We evaluate device performance of SCISSOR-only andSCISSOR + SBS systems for different numbers of cascaded resonators from 1 to 70 using two different datafidelity metrics including eye-opening and mutual information. A practical system design isdemonstrated by analyzing its performance in terms of fractional delay, power transmission,and data fidelity. We observe that the results from the two metrics are in good agreement.Based on system optimization under practical resource and fidelity constraints,the SCISSOR consisting of 70 cascaded resonators provides a fractional delay of ∼ 8 with 22 dB attenuation at a signal bit rate of 10 Gbps. The combined optimal SCISSOR(with 70 resonators) + SBS system provides a improved fractional delay up to ∼ 17 with unit power transmission under the same constraints.

Static and dynamic properties of cavity solitons in VCSELs with optical injection

The static and dynamical properties of cavity solitons in a vertical cavity surface emitting laser with optical injection are investigated. Analytical results about the instabilities affecting the homogeneous steady state are presented. These instabilities play a key role in the determination of the necessary and favorable conditions for cavity soliton existence. Optimization of an all-optical delay line by tuning the injected field frequency leads to a five fold increase of the soliton velocity in the transverse plane. Finally, the phenomenon of cavity soliton merging is applied to combine input signals in optical information processing and to manipulate two dimensional optical memories.

All-optical delay line based on a cavity soliton laser with injection

The motion and position of cavity solitons in a vertical-cavity surface-emitting laser with optical injection are investigated. Spatial variations of the phase of the injected field are considered in the form of sinusoidal and triangular modulations. We show how the velocity, distance traveled, and final position of the cavity solitons can be controlled by varying the slope of the phase modulations and the response time of the semiconductor medium. Numerical simulations demonstrate the feasibility of an all-optical delay line in a cavity soliton laser. Merging of cavity solitons is observed when they collide at modulation maxima and is shown to be beneficial in the operation of the delay line. The merging and consequent emission of pulsed and localized light is explained in terms of violation of energy balance for soliton systems in the presence of injection and dissipation.

Publisher's Note: “All-optical delay line using semiconductor cavity solitons” [Appl. Phys. Lett. 92, 011101 (2008)

First Page

All-optical delay line using semiconductor cavity solitons

An all-optical delay line based on the lateral drift of cavity solitons in semiconductor microresonators is proposed and experimentally demonstrated. The functionalities of the device proposed as well as its performance is analyzed and compared with recent alternative methods based on the decrease of group velocity in the vicinity of resonances. We show that the current limitations can be overcome using broader devices with tailored material responses.

Wide-Bandwidth, Tunable, Multiple-Pulse-Width Optical Delays Using Slow Light in Cesium Vapor

We demonstrate an all-optical delay line in hot cesium vapor that tunably delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns (group index of approximately 200) with little pulse distortion. The delay is made tunable with a fast reconfiguration time (hundreds of ns) by optically pumping out of the atomic ground states.

Optical data packet synchronization and multiplexing using a tunable optical delay based on wavelength conversion and inter-channel chromatic dispersion

10 Gb/s non-return-to-zero (NRZ) on-off keyed (OOK) optical data packets are synchronized and time-multiplexed using a 26-ns tunable all-optical delay line. The delay element is based on wavelength conversion in periodically poled lithium niobate (PPLN) waveguides, inter-channel chromatic dispersion in dispersion compensating fiber (DCF) and intra-channel dispersion compensation with a chirped fiber Bragg grating (FBG). Delay reconfiguration time is measured to be less than 300 ps.

Performance analysis of an optical correlatorreceiver for SIK DS-CDMA communication systems

An all-optical parallel delay line unipolar-bipolar correlator receiver is proposed for SIK DS-CDMA optical fibre communication systems such as LANs and the local loop. The receiver BER performance is assessed as a function of the incident optical power for noncoherent transmission with the number of simultaneous users as a parameter.