1. Uncoordinated Access Transmitters can transmit at any time using an interleaver chosen from a family without informing anyone except the desired receiver Interference is assumed Star network tx 1 tx 2 tx n rx 1 rx 2 rx n … … Channel Coding Channel Model Output 0 if all users transmit 0 Output 1 if one or more users transmit 1 Interleaver Users can be uniquely addressed by interleaver pattern Trellis Code Data bits are protected from collisions using a specially designed non-linear code Reed Solomon Code Ensures that the final data stream has BER<10 -9 Optical OR Channel OR channel 5 other tx Reed Solomon Decoder (255,237) Trellis Decoder Rate:1/20 De-interleaver

2. System Implementation Tx-2 Tx-6 Tx-1 laser modulator amplifier … Optical coupler High Speed Electronic System Optical SystemLogical System laser modulator laser modulator Rx retime thresholding Lightwave detector amplifier 0 3 4 1 2 Optical Receiver Thresholding and Retiming Logic Implementation Interleaver: 1600 bit interleaver Use novel random write-by-row, read-by, column scheme Trellis code: 64 state parallel Viterbi decoding Heavily pipelined Component Integration

3. Interdisciplinary Design Sponsored by Space and Naval Warfare Systems Center – San Diego (N66001-02-1-8938) Channel rate 1.2 Gbps * 6 = 7.2 Gbps Data Rate60Mbps * 6 = 360 Mbps Users Bits tested Errors Found Measured BER 11.5e+110< 6.4e-12 24.6e+100< 2.2e-11 31.2e+90< 8.3e-10 Channel Code Design Trellis code combined with IDMA to protect against interference FPGA Logic Design Novel, parallel and high speed architectures to handle optical rates Electrical / Optical Design Six CW lasers intensity modulated with electrical signals