Suresh Rangarajan

All-optical contention resolution with wavelength conversion for asynchronous variable-length 40 Gb/s optical packets

We present a new all-optical technique for resolving contention between asynchronous variable length packets. The approach utilizes a novel all-optical asynchronous latching switch based on cross-coupled injection-locked wavelength converters. We experimentally demonstrate that the scheme resolves contention between variable-length, asynchronous 40 Gb/s packets with a measured bit error rate of better than 10/sup -9/, without an error floor.

Two-hop all-optical label swapping with variable length 80 Gb/s packets and 10 Gb/s labels using nonlinear fiber wavelength converters, unicast/multicast output and a single EAM for 80- to 10 Gb/s packet demultiplexing

We demonstrate for the first time two hops of all-optical label swapping of variable length 80 Gb/s packets and 10 Gb/s optical labels, with unicast/multicast capability using an all-optical fiber cross-phase modulation wavelength converter.

High-speed optical time-division-multiplexed/WDM networks and their network elements based on regenerative all-optical ultrafast wavelength converters

We describe an optical time-division-multiplexed (OTDM)/WDM network architecture that integrates high-speed optical time-division multiplexing at speeds of 40 Gbit/s and higher with lower-bit-rate WDM channels. An ultrafast wavelength converter is used as a regenerative multifunction building block for OTDM multiplexing, WDM-to-OTDM and OTDM-to-WDM transmultiplexing, OTDM/WDM multicasting, OTDM all-optical label read-write, and all-optical time-channel add-drop multiplexing. Subsystem design and underlying component technologies are described in detail. New results and performance measurements are shown at 40 and at 80 Gbit/s.

All-optical add-drop of an OTDM channel using an ultra-fast fiber based wavelength converter

In conclusion we have demonstrated an all-optical OTDM add-drop multiplexer based on an ultra-fast fiber wavelength converter. A 10 Gb/s data channel is stripped from an incoming 40 Gb/s OTDM signal and a new 10 Gb/s data channel is added in its place and transmitted through 50 km of DSF. A maximum power penalty of 1 dB was obtained between the back-to-back and the worst through going channel. The system is robust to environmental disturbances and the transmitted channels performed well under transmission conditions. A clock-recovery unit can be integrated in the system to achieve synchronization between the incoming data stream and the local drop and through clocks. There is a polarization dependence of about 1 dB in the wavelength converter, however it can be made polarization independent as shown in. This technique can be scaled to very high bit-rates. Using highly non-linear fiber of appropriate dispersion value can increase the bandwidth of conversion to cover the entire C band and also reduce the power requirement.

Synchronizing optical data and electrical control planes in asynchronous optical packet switches

We experimentally demonstrate the use of optical payload envelope detection in a 40 Gbit/s asynchronous optical packet switch to synchronize the optical data and electrical control planes. Measurements show 100% envelope recovery over an 8.5 dB packet power dynamic range.

High Performance MEMS-Based Micro-Optic Assembly for Multi-Lane Transceivers

Advanced transceivers generally require a multi-lane approach, which necessitates the integration of multiple subcomponents. The use of mature, generally available, and low-cost single element components such as electro-absorption modulated lasers, silica planar lightwave circuits, and direct-modulated distributed feedback lasers, integrated in a hybrid fashion and optically aligned with micro-electromechanical systems provides a practical solution. Standard bonding tools with positioning tolerances of approximately ten micrometers are used to populate a silicon microbench that incorporates micro-adjustable elements with various optical components. After diebonding, the positions of coupling microlenses are adjusted to correct for the poor diebond accuracy, and then these movable elements are fixed in place with built-in heaters and solder. The net result is highly uniform, manufacturable, and low loss coupling between the optical elements, with typically 1 to 2 dB of loss. Using this packaging technique, we demonstrate a 40 Gb/s four-channel (4 × 10 Gb/s) DML-based transceiver and a 100 Gb/s ten-channel (10 × 10 Gb/s) EML-based transceiver for 10 and 80 km reach respectively.

All-optical packet compression of variable length packets from 40 to 1500 B using a gated fiber loop

A scalable loop-based packet compression scheme capable of handling variable length Internet protocol packets, from 40 to 1500 B, is proposed and demonstrated. The technique uses per packet variable compression ratio to achieve fixed compressed output packet size independent of input packet size. This technique allows variable length packets to be stored in fixed delay optical buffers and has application to optical packet switching, optical multiplexing, and optical grooming. These results demonstrate the largest packet size compressed to date. Error-free compression and verification of 1500-B packets compression from 2.5 to 10 Gb/s is demonstrated with a measured power penalty of /spl sim/2.2 dB.

Burst mode 10 Gbps optical header recovery and lookup processing for asynchronous variable-length 40 Gbps optical packet switching

We demonstrate 10 Gbps asynchronous optical header recovery with less than 20 bits lock time and over 380 bits hold time after the label end. Layer-1(BER) and Layer-2(Header Loss) results are presented for the first time

Analog performance of an ultrafast sampled-time all-optical fiber XPM wavelength converter

Analog performance of an all-optical ultrafast wavelength converter is measured and reported for the first time. The wavelength-conversion process is based on nonlinear cross-phase modulation in an optical fiber combined with an optical filter to convert phase modulation to amplitude modulation. The spurious-free dynamic range (SFDR) of the converter is measured to be 82 dB/spl middot/Hz/sup 2/3/. We define a new metric called the SFDR power penalty, which measures the degradation in SFDR relative to baseline the back-to-back analog optical link. The SFDR power penalty was measured to be 5 dB/spl middot/Hz/sup 2/3/ and is shown to be a function of the input optical power. This metric is used to characterize the linear region of the optical wavelength converter.

Performance of a label erase and wavelength switching sub-system for layer-3 all-optical label switching using a two stage InP wavelength converter

We experimentally assess the performance of a two-stage wavelength conversion label swapping sub-system operating at OC-48 line-rates and variable length packets with layer-3 traffic control. Wavelength switching times < 6 ns are observed giving insignificant throughput penalties for dynamic wavelength switching.