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High Bit Rate OTDM Link using Polymer All-Optical Switches

Objective

The project is concerned with the development of advanced ultra-fast (2 ps) polymeric all-optical switches. The switches can be demonstrated within a four channel optical time division multiplexed (OTDM) link running at 40 Gbit/s, where they will be used in the demultiplexer to gate-out individual channels. If successful operation is achieved at 40 Gbit/s, the rate will be increased further. The system will employ optical clock pulses derived from mode-locked semiconductor lasers and operate in the third telecom window (1.5 um).
The research is concerned with the development of advanced ultrafast (2 ps) polymeric all optical switches for incorporation into a 4 channel optical time division multiplexed (OTDM) link running at 40 gigabytes per second where they will be used in the demultiplexer to gate out individual channels. The system employs optical clock pulses derived from mode locked semiconducter lasers and operates in the third telecom window (1.5 um).

Three important achievements resulted from the first year of the project:
a packaged and pigtailed polymer, ultrafast, all optical switch has been fabricated. The switch is able to operate in less than 2 ps for gating out pulses in the 40 gigabytes per second OTDM data stream;
a 40 gigabytes per second OTDM system test has been completed;
a new nonlinear optical polymer has been developed with substantially higher nonlinearity which will be used in future switch prototypes to increase further device performance.

Achievements from the second year of the project included:
the demonstration of 40 Gbit/s OTDM transmission with lithium niobate demultiplexing;
fabrication of pigtailed channel waveguide devices in the nonlinear optical polymer poly(3BCMU) with a fibre to fibre insertion loss of less then 6 dB and an integrated optical 4-wave mixer with a cross talk of 19 dB (these devices are being tested);
development of a new nonlinear optical polymer which has a third order nonlinearity which is 8 times greater than that of poly(3BCMU) at 1.55 um wavelength.

OTDM provides a means of substantially increasing capacity on heavily used routes and it is planned to exploit the system being developed for this purpose. OTDM is transparent to any communication protocols used within multiplexed channels. The demultiplexed data is available directly in optical form for local distribution without requiring electrical optical conversion. The technique is therefore compatible with current technology.
Technical Approach

The polymeric all-optical switch demonstrated in RACE I is being developed into an advanced prototype incorporating improved non-linear polymer, channel waveguide geometry and fibre pigtails. This work includes materials research aimed at improving the optical properties of existing materials and developing new materials. During the switch development, intermediate prototypes will be constructed and characterised on the OTDM system testbed.

Key Issues

- Materials development.
- Device development.
- OTDM system construction.
- Integration of switches into system.

Expected Impact

OTDM provides a means of substantially increasing capacity on heavily used routes and it is planned to exploit the system being developed for this purpose. OTDM is transparent to any communication protocols used within multiplexed channels. The de-multiplexed data is available directly in optical form for local distribution without requiring electrical-optical conversion. The technique is therefore compatible with current technology.

Coordinator

University of Dublin
Address
Trinity College,
2 Dublin
Ireland

Participants (4)

British Telecom plc (BT)
United Kingdom
Address
British Telecom Laboratories Martlesham Heath
IP5 7RE Ipswich
ERA Technology Ltd
United Kingdom
Address
Cleeve Road
KT22 7SA Leatherhead
IROE
Italy
Address
Via Panciatichi 64
50127 Firenze
Istituto Guido Donegani SpA
Italy
Address
Via S. Salvo 1
20097 San Donato Milanese