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We present experimental investigations of the dynamical properties of semiconductor optical amplifiers (SOAs) and their impacts in all-optical signal processing using SOAs. We introduce ultrafast optical signal characterization techniques to fully characterize the gain and phase dynamics of SOAs. We elucidate a consequence of the slow carrier recovery as pattern-dependent phase fluctuation in wavelength conversion of on-off -keyed signals. We also analyze the conversion of the phase fluctuation into amplitude fluctuation limiting the performance of all-optical xor operation. Finally, the performance of all-optical wavelength conversion of differential phase-shift-keyed signals is presented with emphasis on regeneration of the phase information. [ABSTRACT FROM PUBLISHER]

The ongoing growth of data traffic from existing and new applications poses a challenge to the packet-switched network infrastructure. High-capacity transport can be achieved in such networks by using dense wavelength-division-multiplexed systems, and reconfigurable optical add-drop multiplexers allow the optical layer to provision wavelength-based circuits between routing nodes. However, construction of the high-capacity packet routers provides significant scaling issues due to complexity, interconnect, and thermal limits. In this paper we will not seek to cover all aspects of optical packet switching and routing but outline some of the challenges facing the construction of such future routers and describe the role photonics can have in overcoming some of these issues. We will discuss how photonics' primary role will be to provide interconnection between racks of electronic routing elements and describe how fast wavelength switching can provide a high-capacity distributed switch fabric that will allow these packet routers to scale to higher capacities. The fast wavelength switching can be seen as the packet analog of wavelength-based circuit switching of today's transparent optical networks [ABSTRACT FROM PUBLISHER]

This paper describes an optical configuration that allows effective arrangement of multiple 1×N optical switches as an integrated array. An experimental compact module of 16 arrayed 1 × 8 optical switches, built by utilizing a cylindrical lens, achieves uniform performance and a mean fiber-to-fiber insertion loss of 2.75 dB. This paper also discusses various layouts that use the proposed optical switching module for both wavelength-independent and wavelength division multiplexing (WDM) applications. [ABSTRACT FROM PUBLISHER]

An all-optical switchable wavelength-converting module at 40 Gb/s line rate is demonstrated in a fully integrated InP chip. The device combines a semiconductor optical amplifier-based wavelength converter and a fast-tunable multifrequency laser. Sub-nanosecond switching among the eight channels of the integrated laser is shown, and error-free operation of the wavelength conversion process at 40 Gb/s for each wavelength is demonstrated. The applications of fast switching wavelength conversion for optical switching and packet routing are discussed. [ABSTRACT FROM PUBLISHER]

The design and performance of several generations of wavelength-selective 1×K switches are reviewed. These optical subsystems combine the functionality of a demultiplexer, per-wavelength switch, and multiplexer in a single, low-loss unit. Free-space optics is utilized for spatially separating the constituent wavelength division multiplexing (WDM) channels as well as for space-division switching from an input optical fiber to one of K output fibers (1×K functionality) on a channel-by-channel basis using a microelectromechanical system (MEMS) micromirror array. The switches are designed to provide wide and flat passbands for minimal signal distortion. They can also provide spectral equalization and channel blocking functionality, making them well suited for use in transparent WDM optical mesh networks. [ABSTRACT FROM PUBLISHER]

This work presents a high-resolution (13.2 GHz) channel-blocking optical filter, suitable for use as a reconfigurable optical add/drop multiplexer (ROADM), which seamlessly supports data rates from 2.5 to 160 Gb/s. The filter consists of a linear array of 64 MEMS micromirrors and a high-dispersion echelle grating. The demonstrated device had an insertion loss of 9 dB, a loss ripple of 1.2 dB, and a group delay ripple of 15 ps. Data transmission through the device with various mixed data rate scenarios ranging from 2.5 to 160 Gb/s showed negligible penalty, except at 40 Gb/s where a maximum penalty of 1.5 dB was observed due to a phase coherence with the blocker filter ripple. [ABSTRACT FROM PUBLISHER]

This paper describes the subsystem design and performance of a 256×256-port micromechanical beam-steering optical cross-connect with 1.33-dB average loss, which can provide 238×238-port cross-connect with a maximum loss of less than 2dB. This paper describes the design chosen and analyzes the tolerance ranges required to produce low loss and simulate the expected loss distribution of the fabric. The method of establishing and testing the connections is also described. The simulation is compared with the measured system, and the expected and measured static and dynamic crosstalk are compared. [ABSTRACT FROM PUBLISHER]

Dynamic gain equalization filters (DGEFs) are important for high-performance wavelength division multiplexed (WDM) communications. One of the first demonstrated DGEF used a micromechanical etalon filter array illuminated with free-space spectral demultiplexing optics. Here, we present subsequent research on etalon-based dynamic spectral filters, including vertical device structures which linearize and reduce the drive voltage from 70 to 40 V, and spatially-segmented etalons which allow channelized spectral equalization and further reduce drive voltage. We describe a prototype using a simplified cylindrical optomechanical package with a 104-nm broadband spectral response, 7.5-dB insertion loss and less than 16-V operation voltage. Finally, we show the use of a 42-nm bandwidth DGEF prototype with feedback stabilization to more than double the number of channels and operating bandwidth of a conventional Erbium-doped fiber amplifier while maintaining < 1-dB power uniformity. [ABSTRACT FROM PUBLISHER]

This paper describes the design and performance of a 64-channel equalization and blocking filter. It utilizes a free space lens and grating multiplexer with micromechanical tilt mirrors providing variable attenuation. The module achieves a 5-dB insertion loss with a 3-dB passband of 87 GHz for 100-GHz spaced channels. The attenuation range achieved is in excess of 35 dB, making it suitable for wavelength blocking in switching applications. The device has been demonstrated to be compatible with 10- and 40-Gb/s transmission. [ABSTRACT FROM PUBLISHER]

This paper describes a continuously variable and independently addressable channelized dispersion compensator. The optical system is a free-space grating-based system used in a four-pass configuration to ensure flat passbands. The variable dispersion is produced by an array of thermally adaptable curvature micromechanical mirrors. A per-channel variable dispersion greater than +/-400 ps/nm has been demonstrated, with 58 GHz +/-0.4 dB flat passband on 85 GHz spacing. The group delay ripple is less than 7 ps and the penalty with 40 Gb/s CSRZ is 0.7 dB. [ABSTRACT FROM PUBLISHER]

This paper analytically and experimentally examines node architectures for wavelength-routing networks, with emphasis on the degree of wavelength conversion provided. Wavelength flexibility simplifies network management and increases network capacity but requires large cross-connects and deployment of wavelength converters (WCs). A simple probabilistic model is used to upper-bound the number of WCs required at a network node, under dynamic traffic load. When provisioned in a shareable pool, with a fixed number of wavelength channels per fiber, the number of WCs required remains low as overall network capacity is scaled up. Motivated by this analysis, experiments demonstrate the feasibility of implementing wavelength-flexible network nodes using large microelectromechanical (MEMS)-based cross-connects and all-optical WCs. In one design, WCs were attached directly to cross-connect output ports, and in another, they were attached in a loop-back fashion to allow sharing. Error-free transmission at 10 Gb/s was demonstrated in both cases. [ABSTRACT FROM PUBLISHER]

This paper describes Si-micromachined two-axis beam-steering micromirrors and their performance in 256 × 256- and 1024 × 1024-port large optical cross-connects (OXCs). The high-reflectivity wavelength-independent mirrors are electrostatically actuated; capable of large, continuous, controlled, dc tilt in any direction at moderate actuation voltages; and allow setting times of a few milliseconds. Packaged two-dimensional (2-D) arrays containing independently addressable identical 256 and 1296 mirrors are used to build fully functional bitrate and wavelength-independent single-stage, low-insertion-loss, single-mode fiber OXC fabrics. [ABSTRACT FROM PUBLISHER]

We present the concept of using image plane transformations with free-space diffraction-grating-based multiplexers. We demonstrate two examples of a diffraction-grating-based multiplexer that take advantage of image plane spatial transformations. We show that the use of such spatial transformations has unique advantages for multiplexing schemes. We also demonstrate unique system applications enabled by these multiplexers. [ABSTRACT FROM PUBLISHER]

We present the first optical equalizer realized on Indium Phosphide material that is also monolithically integrated with a semiconductor optical amplifier. We show that the device can mitigate inter-symbol interference arising from narrowband optical filtering of 40-Gb/s non-return-to-zero data. Significant improvement in the measured bit-error rates after optical equalization of the filtered signal is reported. It is shown that the device can also mitigate the impairments arising from residual chirp and electrical filtering in the transmitter and receiver. [ABSTRACT FROM PUBLISHER]

The effect of p-type doping of the active region of multiple quantum-well (MQW) semiconductor optical amplifiers (SOAs) has been studied. Spectrogram measurements of the dynamics of the SOAs reveal that using p-doped barriers for the MQWs has significantly reduced both gain and phase recovery times. 1/e phase recovery times as short as 11 ps were demonstrated using this approach [ABSTRACT FROM PUBLISHER]

The authors demonstrate a wavelength (de)mux that is dispersion-free and has significantly better figure-of-merit, defined as 1-dB bandwidth over 20-dB bandwidth, over existing devices. A four-channel demux has been fabricated and the figure-of-merit is 97%. A practical system application of this device has also been demonstrated. [ABSTRACT FROM PUBLISHER]

We experimentally demonstrate an optical duobinary transmission system employing a phase modulator and a narrow-bandwidth optical filter. Compared to the conventional duobinary signal generated by using an electrical low-pass filter, the demonstrated duobinary signal 1) provides improved receiver sensitivity; 2) overcomes the problem associated with word lengths; and 3) substantially relaxes the performance sensitivity to the driver and modulator response, while maintaining narrow spectral bandwidth and high dispersion tolerance. [ABSTRACT FROM PUBLISHER]

We present a device which produces changes in the slope of its transmitted spectra via an applied bias, a spectrally linear optical power equalizer (SLOPE) device. This device may have application for equalizing power levels in optical networks when simple gain tilt is all that is required, for example in optical power amplifiers [ABSTRACT FROM PUBLISHER]