Abstract-We show that the use of a long semiconductor optical amplifier increases the error-free conversion interval of a four-wave mixing (FWM)-based wavelength converter. 30-nm wavelength down-conversion and 15-nm up-conversion have been obtained at 10 Gb/s. This result is a significant improvement over the previous best performance of a FWM-based wavelength converter and suggests that the full erbium-doped fiber amplifer bandwidth can be covered with FWM wavelength converters.
Ultrafast all-optical logic gates that accept optical inputs in which wavelength designates bit position within the overall byte are proposed and demonstrated. Four-wave mixing is shown to provide a conditional test function that can be used to construct any multi-input logic gate. Polarization provides the logic state for each bit. Implementations that use semiconductor optical amplifiers as the four-wave mixing medium can be monolithic and compact.
Abstract-We give a general expression for the polarization dependence of the four-wave mixing (FWM) efficiency in the dual-pump configuration. This expression, along with some general properties of the FWM susceptibility tensor, is used to propose a simple scheme to generate a nearly (1.5-dB variation) polarization independent FWM converted signal. The viability of this scheme is verified in a wavelength conversion experiment at 2.5 Gbls.AVELENGTH converters are essential devices to ex-W ploit the full fiber bandwidth in a wavelength division multiplexed network. Four-wave mixing (FWM) in semiconductor optical amplifiers (SOA) is a strong candidate to implement this function [l], [2]. Its intrinsic advantages include transparency to the modulation format and bit rate of the input signal, multiterahertz response bandwidth, small intrinsic chirp, ease and versatility of channel wavelength switching. In its usual single-pump+onfiguration, the wavelength converted signal intensity strongly depends on the polarization state of the pump and the probe (input signal). Since most of the fiber used in telecommunication networks is not polarization maintaining, all system components should operate independently of the polarization of the signal waves.In general, there is no single-pump polarization setting which allows polarization independent FWM conversion [ 3 ] . In bulk amplifiers, Jopson [4] has demonstrated that any two orthogonal pump polarizations can be used in principle to obtain a wavelength conversion efficiency that is independent of the probe polarization. This is true for all isotropic media, and it has been demonstrated in a fiber four-wave mixing wavelength converter [5].Strained quantum-well amplifiers have anisotropic active regions, and the FWM efficiency depends on the absolute and the relative polarizations of the pump and the probe.In general, the conversion efficiency from two orthogonal pumps will still depend on the probe polarization, and to achieve independence, the exact polarizations have to be calculated using conversion efficiency matrices. For the carrier density modulation and canier heating FWM contributions [n the dual-pump configuration, the converted signal of interest can be described in terms of two such matrices, one corresponding to the conversion efficiency at the detuning between the signal and the first pump, and other for the detuning with the second pump. Thus, in general, to compute the polarization state of the two pumps for which the conversion efficiency is exactly independent of the probe polarization, eight conveirsion parameters must be known for each wavelength configuration.In this letter, we present an approach using altematingstrain quantum-well SOH'S [61, for which there is a simple pump configuration yielding nearly-polarization independent wavelength conversion. No material parameters need to be determined, and the melhod can be applied for almost any wavelength shift, anywhere within the gain spectrum of the amplifier. We demonstrate the feasbility of this sch...
Polarization-resolved four-wave mixing spectroscopy is used to study interwell carrier dynamics in an alternating-strain multiquantum-well optical amplifier. The experimental data are found to be in good agreement with a simple model based on quantum capture/escape and diffusion processes. The results suggest that the interwell transport in this structure is mainly limited by carrier escape, and give an estimate of 16 ps for the overall transport lifetime. © 1996 American Institute of Physics. ͓S0003-6951͑96͒04753-5͔Interwell carrier transport in semiconductor multiquantum-well structures is a highly nonlinear process with significant implications to the use of these structures in electrical and optical devices. Of particular interest is the finite rate at which the carrier densities in neighboring wells reach equilibrium with one another and with the distribution of unconfined carriers in the barrier region. This process has received considerable attention in recent years 1-8 since it has been associated with nonlinear gain compression, and hence the maximum modulation bandwidth of quantum-well lasers.In this letter, we report on a simple experiment aimed at measuring the rate at which modulated carrier distributions are transferred between neighboring quantum wells. This measurement is based on polarization-resolved four-wave mixing ͑FWM͒ spectroscopy in an InGaAsP alternatingstrain semiconductor optical amplifier ͑SOA͒, consisting of three pairs of tensile and compressively strained quantum wells.9 In a recent article 7 it was shown how this technique enables selective excitation and probing of adjacent quantum wells, and the effect of interwell transport was qualitatively observed. Here we apply the results of a subsequent detailed study of the polarization properties of FWM 10 to also obtain quantitative information. In particular, a fit of the experimental data to a simple model gives an estimated 16 ps for the interwell transport lifetime in the structure measured.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.