Paul J. Maguire

Chromatic Dispersion Monitoring of 80-Gb/s OTDM Data Signal via Two-Photon Absorption in a Semiconductor Microcavity

In this letter, a novel method of chromatic dispersion monitoring via two-photon absorption (TPA) is investigated. A specially designed semiconductor microcavity is employed as a TPA detector for monitoring data signals operating at rates up to 80Gb/s. As the microcavity has a wavelength-dependent response, a single device can be used to monitor multiple channels in a multiwavelength optical telecommunication system

Self-seeding of a gain-switched integrated dual-laser source for the generation of highly wavelength-tunable picosecond optical pulses

The authors demonstrate the generation of nearly transform-limited optical pulses that are wavelength tunable over almost 50 nm. The wide tuning range is obtained by self-seeding a gain-switched source containing two Fabry-Perot lasers, and employing a widely tunable Bragg grating in the feedback loop. The generated pulses exhibit Side-mode suppression ratios of 50 dB above and across the full tuning range.

Optical signal processing via two-photon absorption in a semiconductor microcavity for the next generation of high-speed optical communications network

Due to the introduction of new broadband services, individual line data rates are expected to exceed 100 Gb/s in the near future. To operate at these high speeds, new optical signal processing techniques will have to be developed. This paper will demonstrate that two-photon absorption in a specially designed semiconductor microcavity is an ideal candidate for optical signal processing applications such as autocorrelation, sampling, and demultiplexing in high-speed wavelength-division-multiplexed (WDM) and hybrid WDM/optical time-division-multiplexed networks.

Resonance tuning of two-photon absorption microcavities for wavelength-selective pulse monitoring

We show the potential use of a single photodetector for multichannel pulse monitoring. Two-photon absorption in a microcavity structure is used as the nonlinear optical technique for pulse monitoring. Angle tuning of the device allows the resonance to be tuned. For the device studied here that is optimized for 2-ps pulses, a possible tuning range of 55 nm is shown.

Chromatic Dispersion Monitoring for High-Speed WDM Systems Using Two-Photon Absorption in a Semiconductor Microcavity

This paper presents a theoretical and experimental investigation into the use of a two-photon absorption (TPA) photodetector for use in chromatic dispersion (CD) monitoring in high-speed, wavelength division multiplexing network. In order to overcome the inefficiency associated with the nonlinear optical-to-electrical TPA process, a microcavity structure is employed. An interesting feature of such a solution is the fact that the microcavity enhances only a narrow wavelength range determined by device design and angle at which the signal enters the device. Thus, a single device can be used to monitor a number of different wavelength channels without the need for additional external filters. When using a nonlinear photodetector, the photocurrent generated for Gaussian pulses is inversely related to the pulse width. However, when using a microcavity structure, the cavity bandwidth also needs to be considered, as does the shape of the optical pulses incident on the device. Simulation results are presented for a variety of cavity bandwidths, pulse shapes and durations, and spacing between adjacent wavelength channels. These results are verified experimental using a microcavity with a bandwidth of 260 GHz (2.1 nm) at normal incident angle, with the incident signal comprising of two wavelength channels separated by 1.25 THz (10 nm), each operating at an aggregate data rate of 160 Gb/s. The results demonstrate the applicability of the presented technique to monitor accumulated dispersion fluctuations in a range of 3 ps/nm for 160 Gb/s return-to-zero data channel.

Reduction of Multiple Access Interference in a DS-OCDMA System via Two-Photon Absorption

We demonstrate a technique to suppress multi-access interference in an OCDMA system by using the nonlinear process of two-photon absorption. This allows the extinction ratio to be improved by 5 dB when compared to linear detection.

All-optical sampling and spectrographic pulse measurement using cross-absorption modulation in multiple-quantum-well devices

The application of cross absorption modulation for optical sampling and phase sensitive pulse measurement is presented. Both a commercial 40 GHz electroabsorption modulator and a vertical microcavity saturable absorber are used to sample a 2 ps pulse train at 40 GHz. The modulator was then used to make cross-absorption modulation based frequency-resolved optical gating (FROG) measurements. The results were verified by comparison with a commercial optical sampling oscilloscope and the more standard second harmonic generation FROG technique.

High-speed chromatic dispersion monitoring of a two-channel WDM system using a single TPA microcavity

Chromatic dispersion monitoring of two 160 Gb/s wavelength channels using a TPA Microcavity is presented. As the microcavity exhibits a wavelength resonance characteristic, a single device could monitor a number of different WDM-channels sequentially.

Investigation of SOA-based wavelength conversion at 80 Gb/s using bandpass filtering

This paper presents a simple and effective 80 Gb/s wavelength conversion scheme by using Cross Gain Modulation in a Semiconductor Optical Amplifiers (SOA) in conjunction with filtering the blue shifted component of the probe spectrum to give a non-inverted output signal.

Dispersion Monitoring for High-Speed WDM Networks via Two-Photon Absorption in a Semiconductor Microcavity

Due to the continued demand for bandwidth, network operators have to increase the data rates at which individual wavelengths operate at. As these data rates will exceed 100 Gbit/s in the next 5-10 years, it will be crucial to be able to monitor and compensate for the amount of chromatic dispersion encountered by individual wavelength channels. This paper will focus on the use of the novel nonlinear optical-to-electrical conversion process of two-photon absorption (TPA) for dispersion monitoring. By incorporating a specially designed semiconductor microcavity, the TPA response becomes wavelength dependent, thus allowing simultaneous channel selection and monitoring without the need for external wavelength filtering