Ultrafast Nonlinear Interferometer Research Articles

10-Gb/s All-Optical Half-Adder With Interferometric SOA Gates

In this letter, we report an all-optical module that generates simultaneously four Boolean operations at 10 Gb/s. The circuit employs two cascaded ultrafast nonlinear interferometers and requires only two signals as inputs. The first gate is configured as a 2 /spl times/ 2 exchange-bypass switch and provides OR and AND logical operations. The second gate generates XOR (SUM bit) and AND (CARRY bit) Boolean operations and constitutes a binary half-adder. Successful operation of the system is demonstrated with 10-Gb/s return-to-zero pseudorandom data patterns.

Ultrafast nonlinear interferometer (UNI)-based digital optical circuits and their use in packet switching

Digital optical logic circuits capable of performing bit-wise signal processing are critical building blocks for the realization of future high-speed packet-switched networks. In this paper, we present recent advances in all-optical processing circuits and examine the potential of their integration into a system environment. On this concept, we demonstrate serial all-optical Boolean AND/XOR logic at 20 Gb/s and a novel all-optical packet clock recovery circuit, with low capturing time, suitable for burst-mode traffic. The circuits use the semiconductor-based ultrafast nonlinear interferometer (UNI) as the nonlinear switching element. We also present the integration of these circuits in a more complex unit that performs header and payload separation from short synchronous data packets at 10 Gb/s. Finally, we discuss a method to realize a novel packet scheduling switch architecture, which guarantees lossless communication for specific traffic burstiness constraints, using these logic units.

Clock and data recovery circuit for 10-Gb/s asynchronous optical packets

We demonstrate an all-optical clock and data recovery circuit for short asynchronous data packets at 10-Gb/s line rate. The technique employs a Fabry-Perot filter and a SOA-based ultrafast nonlinear interferometer (UNI) to generate the local packet clock, followed by a second UNI gate to act as decision element, performing a logical AND operation between the extracted clocks and the incoming data packets. The circuit can handle short packets arriving at time intervals as short as 1.5 ns and arbitrary phase alignment.

40 Gb/s all-optical write/store memory using a single semiconductor optical amplifier-based logic gate

We demonstrate an all-optical regenerative memory with full write/store capability of 40 Gb/s data pack- ets. The memory uses an ultrafast nonlinear interferometer logic gate and does not perform data inverting in each pass. Regenerative storage of variable-length data packets with low switching energies and different storage times is verified. © 2003 Society of Photo-Optical Instrumentation Engineers. (DOI: 10.1117/1.1617313)

All-optical clock recovery from short asynchronous data packets at 10 Gb/s

In this letter, we demonstrate clock extraction from 10-Gb/s asynchronous short data packets. Successful clock acquisition is achieved from data packets arriving at time intervals of only 1.5 ns, irrespective of their precise phase relation. The clock recovery circuit used consists of a Fabry-Perot filter and an ultrafast nonlinear interferometer gate and requires very short time for synchronization.

All-optical pulse regeneration in an ultrafast nonlinear interferometer with Faraday mirror polarization stabilization

We demonstrate the folded ultrafast nonlinear interferometer (FUNI) as a 3R all-optical regenerator. Faraday rotation provides inherent polarization stabilization, and the optical fiber nonlinear medium provides ultrafast operation and switching window tunability. We demonstrate 3R regeneration of 10-Gbit/s data with 5-pJ pulse switching energy and 4-ps timing-jitter tolerance.

Simultaneous high speed OTDM add-drop multiplexing using GT-UNI switch

The authors describe the excellent capability of an all-optical gain-transparent ultrafast nonlinear interferometer (GT-UNI) in dropping, passing through, and adding optical time domain multiplexing (OTDM) channels. Error free operation without significant penalties of a complete OTDM add-drop node at 80 Gbit/s was achieved.

All-optical packet address and payload separation

An all-optical address and data separation scheme is presented for short 10-Gb/s packets. The technique uses a novel packet clock recovery circuit that consists of a Fabry-Perot filter and a ultrafast nonlinear interferometer (UNI) gate to generate a local packet clock. A second cascaded UNI gate is used to separate the header and the payload, performing a simple AND operation between the packet and its self-derived clock. The proposed technique requires a small number of bits as guard band and this number is independent of the line rate.

100 Gb/s optical time-division multiplexed networks

We present ultrafast slotted optical time-division multiplexed networks as a viable means of implementing a highly capable next-generation all-optical packet-switched network. Such a network is capable of providing simple network management, the ability to support variable quality-of-service, self-routing of packets, scalability in the number of users, and the use of digital regeneration, buffering, and encryption. We review all-optical switch and Boolean logic gate implementations using an ultrafast nonlinear interferometers (UNIs) that are capable of stable, pattern-independent operation at speeds in excess of 100 Gb/s. We expand the capability provided by the UNI beyond switching and logic demonstrations to include system-level functions such as packet synchronization, address comparison, and rate conversion. We use these advanced all-optical signal processing capabilities to demonstrate a slotted OTDM multiaccess network testbed operating at 112.5 Gb/s line rates with inherent scalability in the number of users and system line rates. We also report on long-haul propagation of short optical pulses in fiber and all-optical 3R regeneration as a viable cost-effective means of extending the long-haul distance of our OTDM network to distances much greater than 100 km.

Optically addressable 2 x 2 exchange/bypass packet switch

In this letter, we demonstrate an optically addressable 2 /spl times/ 2 exchange-bypass switch operating with 10-Gb/s data packets. Switching is achieved at the bit level using an ultrafast nonlinear interferometer gate with two input data signals and a single control signal. The bit error rate of the switch in a static configuration was estimated to be 10/sup -11/ using synchronous digital hierarchy 64 data frames.

Comparison of interferometric all-optical switches for demultiplexing applications in high-speed OTDM systems

We have investigated three interferometric all-optical switches based on cross-phase modulation (XPM) in semiconductor optical amplifiers (SOAs), the semiconductor laser amplifier in a loop mirror (SLALOM) switch, the Mach-Zehnder interferometer (MZI) switch, and the ultrafast nonlinear interferometer (UNI) switch. Switching windows with different widths are measured under similar conditions for all three switching configurations. We introduce the integrated contrast ratio (ICR) as a measure to evaluate the performance of a switch from switching windows. Using the ICR, the switches are compared and their application is discussed as demultiplexer in optical time division multiplexing (OTDM) systems for data rates of 40, 80, and 160 Gb/s.

Characterization of switching windows of an 160-Gb/s all-optical demultiplexer with data base rates of 10 and 40 Gb/s

Theoretical and experimental switching windows for all-optical demultiplexing from 160 to 10 Gb/s and 40 Gb/s, using a gain-transparent ultrafast nonlinear interferometer are presented. Based on these results we determined the maximum transmittance and the integrated contrast ratio, measures for switching losses and crosstalk from neighboring channels, respectively. Demultiplexing to 40 Gb/s (as compared to 10 Gb/s) leads to 6 dB lower maximum transmittance and 3 dB higher integrated contrast ratio (lower crosstalk).

Demultiplexing of 80-Gb/s pulse-position modulated data with an ultrafast nonlinear interferometer

Pulse-position modulation may be used to reduce patterning effects arising from gain saturation in all-optical switches employing semiconductor optical amplifiers. We present a novel technique for return-to-zero pulse-position modulation of data suitable for use in optical time-division-multiplexed (OTDM) networks. We demonstrate two methods for all-optical demultiplexing of a pulse-position modulated data stream using an ultrafast nonlinear interferometer. Error-free operation is obtained for demultiplexing from OTDM data rates as high as 80 Gb/s with control pulse energies of 25 fJ.

160-Gb/s polarization insensitive all-optical demultiplexing using a gain-transparent ultrafast nonlinear interferometer (GT-UNI)

We report on a polarization-insensitive all-optical demultiplexer based on gain-transparent operation of a semiconductor optical amplifier in an ultrafast nonlinear interferometer (GT-UNI) using polarization diversity. Error-free demultiplexing from 160 to 10 Gb/s is demonstrated.

160-Gb/s all-optical demultiplexing using a gain-transparent ultrafast-nonlinear interferometer (GT-UNI)

We report on an all-optical demultiplexer based on gain-transparent operation of a semiconductor optical amplifier (SOA) in an ultrafast-nonlinear interferometer (GT-UNI). The GT-UNI comprises a robust fiber-chip setup in a folded geometry. For switching window widths of 5.2 ps and 6.0 ps, error-free demultiplexing of 160-10 Gb/s is demonstrated.

20 Gb/s all-optical XOR with UNI gate

All-optical Boolean XOR is demonstrated on a 20 Gb/s pseudodata pattern using a semiconductor optical amplifier-based ultrafast nonlinear interferometer (UNI) switch. Bit pattern switching with low-pattern dependence and low switching energies is achieved.

All-optical write/read memory for 20 Gbit/s data packets

A writable all-optical memory for variable length, 20 Gbit/s data packets is demonstrated. The memory uses an ultrafast nonlinear interferometer (UNI) gate and does not perform data inverting in each pass. Regenerative storage with low switching energies is verified.

100-Gbit/s bitwise logic

We demonstrate 100-Gbit/s bitwise logic in an all-optical semiconductor optical amplifier-based switching device, the ultrafast nonlinear interferometer. To the best of our knowledge this is the first demonstration of 100-Gbit/s AND and INVERT functionality with a 100-GHz optical clock stream and a 100-Gbit/s data stream as the logical inputs to a semiconductor-based switch. Additionally, 100-Gbit/s inverting and noninverting all-optical wavelength conversion are demonstrated.

Interferometric all-optical switches for ultrafast signal processing

All-optical switches find applications in ultrahigh-speed network-user interfaces and in specialized high-speed processors, such as data regenerators and encryptors and microwave signal generators. We describe a semiconductor optical-amplifier-based single-arm interferometric switch called the ultrafast nonlinear interferometer. We discuss how the gain and the refractive-index nonlinearities in semiconductor optical amplifiers have an impact on the all-optical switch design, and we review experimental results obtained with the ultrafast nonlinear interferometer.

40-Gbit/s all-optical circulating shift register with an inverter

We report what is believed to be the first demonstration of an all-optical circulating shift register using an ultrafast nonlinear interferometer with a polarization-insensitive semiconductor optical amplifier as the nonlinear switching element. The device operates at 40 Gbits/s, to our knowledge the highest speed demonstrated to date. Also, the demonstration proves the cascadability of the ultrafast nonlinear interferometric switch.