Optical Data Centers Router Design with Fiber Delay Lines and Negative Acknowledgement

Optical packet switch/optical interconnect will be integral part of high speed switching and datacenter applications. In recent past Arrayed Waveguide Grating (AWG) based designs have shown promising solutions for contention resolution and packet routing. Most of the designs take the advantage of wavelength parallelism and wavelength-based routing nature of AWG. In general, two classes of design have emerged: buffer less and with buffer. In recent past the concept of All-Optical Negative Acknowledgement (AO-NACK) is introduced in case of buffer-less design. Here, in case of dropping of packet a negative acknowledgement is send back to the sender to re-transmit the packet. The drawback of the scheme is that the numbers of re-transmitted packets are huge in buffer less design. In this paper, a buffer-based design is presented where both buffer and negative acknowledgement is utilized to reduce the number of transmitted packets to 3000 times compare with buffer less design, in case of transmission of 106packets. Moreover, negative acknowledgement hardware design is simplified significantly.