Stable Optical Frequency-Locked Multicarriers Generation by Double Recirculating Frequency Shifter Loops for Tb/s Communication

• Published in: Journal of lightwave technology Vol. 30; no. 24; pp. 3938 - 3945
• Main Authors: Zhang, Junwen, Yu, Jianjun, Chi, Nan, Shao, Yufeng, Tao, Li, Zhu, Jiangbo, Wang, Yuanquan
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 15.12.2012; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Coherence; Coherent and frequency-locked subcarrier generation; Erbium-doped fiber amplifier; Exact sciences and technology; Information, signal and communications theory; Modulation, demodulation; Multiplexing; OFDM; optical orthogonal frequency division multiplexing (OFDM); Phase modulation; recirculating frequency shifting; Signal and communications theory; single-sideband (SSB) modulation; Telecommunications and information theory; Performance evaluation; Modulator; Frequency locking; Multicarrier; Spacing; Recirculation; Optical frequency; Clock; Subcarrier; Timbre; Amplified spontaneous emission; Frequency shift; recirculating frequency shifting; Modulation; optical orthogonal frequency division multiplexing (OFDM); Orthogonal frequency division multiplexing; Feasibility; Phase delay; Coherent and frequency-locked subcarrier generation; Single sideband; single-sideband (SSB) modulation
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2012.2206371

We propose and experimentally demonstrate a novel scheme to generate optical frequency-locked multicarriers by using double recirculation frequency shifter loops based on different frequency shifting direction single-sideband modulation in I/Q modulators driven by RF clock signals. By changing the phase difference of I and Q RF drive signal, each loop generates long wavelength and short wavelength subcarriers, respectively. The tone-to-noise ratio (TNR) performance with amplified spontaneous emission noise and the effect of polarization state are theoretically analyzed and experimentally investigated for the first time. Experimental results are in good agreement with the theoretical analysis. Using this scheme, we successfully generate 104 frequency-locked subcarriers with TNR larger than 17 dB and carrier spacing at 12.5 GHz covering 10.21 nm from 1545.01 to 1555.22 nm which shows that this scheme has great potential in future Tb/s per channel communications. The feasibility of this scheme is demonstrated by the experimental results.