# Exploring a New Adaptive Routing Based on the Dijkstra Algorithm in Optical Networks-on-Chip  
[PERSON]  
1 School of Electronic and Information Engineering, Southwest University, Chongqing 400715, China; [EMAIL_ADDRESS] (Y.-L.Z. ); [EMAIL_ADDRESS] (T.-T.S. ); [EMAIL_ADDRESS] (J.-X.C. ); [EMAIL_ADDRESS] (X.-Y.Y. ); [EMAIL_ADDRESS] (M.-M.Y. ); [EMAIL_ADDRESS] (Y.-C.Z. );  
[PERSON]  
1 School of Electronic and Information Engineering, Southwest University, Chongqing 400715, China; [EMAIL_ADDRESS] (Y.-L.Z. ); [EMAIL_ADDRESS] (T.-T.S. ); jcchai@email. to reduce the number of hops of routing path so as to yield lower energy consumption. Recently, an optimized routing algorithm based on Gaussian-based ONoCs was proposed to improve the optical signal-to-noise ratio (OSNR) [8]. The length-optimized-routing-protocol (LORP) [1] was designed to select the preferred option with the smallest number of hops in a virtual cluster in mesh. A new algorithm [9] to select the routing path with the lowest power consumption was proposed to reduce the power loss and raise the OSNR. It improves the transmission quality of the optical signal and lowers energy consumption. The external laser power was reduced by optimizing the circuit in previous studies [10; 11; 12]. Runtime power management techniques have been proposed to reduce the magnitude of laser power consumption by tuning the network in response to actual application characteristics [13; 14]. The traditional power control method is to compare the maximum power of each node and select the maximum power value among them to allocate it to each node. Based on this, a method based on time division multiplexing was proposed to optimized it and save on total laser power in [15]. It is known that adaptive power control (APC) could save energy and reduce power consumption. The APC was firstly proposed to decrease the total power consumption, and then the APC was applied in [16; 17; 18; 19; 20]. In [20], the overall SNR was improved by the combination of APC and the new clustering design. The APC adjusts the transmission loss of each link according to the ratio between the signal transmission loss and the maximum transmission loss. However, considering that only the link with the largest transmission loss makes full use of the power in APC, there is still more power wasted in other links of the network. Focusing on this issue, we used the Dijkstra algorithm to realize a new adaptive routing method which achieves minimum transmission loss for every link in mesh-based ONoCs. In this paper, the Dijkstra algorithm takes the port-to-port transmission loss of the router as the weight value between neighboring routers and selects the next route by comparing the weight values. Considering that the Dijkstra algorithm is globally optimal, it can select the routing path with the minimum transmission loss of each link in a network. We evaluated the power relationship between the optical transmitter and the optical receiver during the transmission of an optical signal on a silicon photonic link. The output power of the optical transmitter on a silicon photonic link depends on the transmission loss of the optical switching device, the transmission loss of the waveguides, and the sensitivity of the receiver. On the premise of keeping the receiver's sensitivity unchanged, the power consumption can be decreased by reducing the link transmission loss. The implementation of optimized power control based on the Dijkstra algorithm can achieve the minimum link transmission loss and greatly reduce the power consumption of the whole network. By the transmission loss analysis model and numerical simulations, we found when the network sizes are \(5\times 5\), \(6\times 6\), \(7\times 7\), and \(8\times 8\), the optimized average output power can reach \(-15.6376\), \(-15.3482\), \(-15.1276\), and \(-14.9548\) dBm respectively. Regarding network performance, the traditional and optimized networks reached saturation when the offered loads were 0.1 and 0.08, and 0.06 and 0.04, respectively.