Design and analysis of redundant optical comb for data center networks

We propose the design of a free spectral range (FSR) and center wavelength tunable redundant optical comb based on a Sagnac loop mirror (SLM) and bidirectional Mach-Zehnder modulator (BMZM). The optical signal from a continuous wave (CW) laser is split into two parts, one part travels in the clockwise direction and the other part travels in the counter clockwise direction inside the SLM and each is modulated by a sinusoidal RF signal that drive the BMZM. The modulation of the CW optical signals with sinusoidal RF signal using BMZM results into the generation of two similar optical combs inside the SLM which consist of 67 stable comb lines. The control of the presence of the combs at the output ports of the SLM can be achieved using a polarization controller (PC) that is located inside the loop. The results show the generation of optical combs with flatness of 2.5 dB, linewidth of 0.005 nm, unwanted-mode suppression ratio (UMSR) of over 47 dB and optical signal to noise ratio (OSNR) of 62 dB.