Ultrafast Nonlinear Optical Signal Processing
We use nonlinear phenomena in semiconductor devices and nonlinear fibers to implement all-optical nonlinear signal processing functions, which can greatly enhance the performance of ultrafast communication networks through the supression noise, enhancement of bandwidth, and preservation of signal integrity. We study novel devices and their applications, including optical thresholding, auto-correlation peak extraction, demultiplexing, physical layer security enhancement, and interferometric noise suppression.
B. J. Shastri*, J. Chang*, A. N. Tait, M. P. Chang, B. Wu, M. A. Nahmias, and P. R. Prucnal, “Ultrafast Optical Techniques for Communication Networks and Signal Processing,” in All-Optical Signal Processing for Data Communication and Storage Applications, Springer Berlin Heidelberg, 2014, ch. 11, 20 pages (in press). [*equal contribution].
A. N. Tait, B. J. Shastri, M. A. Nahmias, M. P. Fok, and P. R. Prucnal, “The DREAM: an integrated photonic thresholder,” IEEE/OSA Journal of Lightwave Technology, vol. 31, no. 8, pp. 1263–1272, Apr. 2013.
J. Chang, M. P. Fok, J. Meister, and P. R. Prucnal, "A single source microwave photonic filter using a novel single-mode fiber to multimode fiber coupling technique", Optics Express, vol. 21, no. 5, pp. 5585–5593, Jan. 2013.
Y. Tian, Y.-K. Huang, S. Zhang, P. R. Prucnal, and T. Wang, “Demonstration of digital phase-sensitive boosting to extend signal reach for long-haul WDM systems using optical phase-conjugated copy," Optics Express, vol. 21, no. 4, pp. 5099–5106, Feb. 2013.
B. J. Shastri, P. R. Prucnal, and D. V. Plant, “A 20-GSample/s (10 GHz × 2 clocks) burst-mode CDR based on injection-locking and space sampling for access networks,” IEEE Photonics Journal, vol. 4, no. 5, pp. 1783–1793, Oct. 2012; invited paper.
N. S. Rafidi, K. S. Kravtsov, Y. Tian, M. P. Fok, M. A. Nahmias, A. N. Tait, and P. R. Prucnal, “Power transfer function tailoring in a highly Ge-doped nonlinear interferometer-based all-optical thresholder using offset-spectral filtering,” IEEE Photonics Journal, vol. 4, no. 2, pp. 528–534, Apr. 2012.
J. Chang, N. Cvijetic, T. Wang, and P.R. Prucnal, “Adaptive photonic beamforming for physical layer security of mobile signals in optical fronthaul networks,” submitted to Frontiers in Optics (FIO), Tucson, AZ, USA, Oct. 2014, paper FTh1B.
Y. Tian, M. P. Fok, and P. R. Prucnal, “A timing jitter insensitive logic gate using tunable gain dynamics in an SOA and optical thresholding,” in Proc. Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, USA, paper CTh4L.
Y. Shechtman, B. J. Shastri, B. Wu, P. R. Prucnal, and M. Segev, “Coupled waveguides for optical multiplexing in high-performance interconnects,” in Proc. Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, USA, Jun. 2013, paper CTu2J.8.
M. P. Chang and P. R. Prucnal,“Amplitude-invariant fast light in a semiconductor optical amplifier for microwave photonics,” in Proc. Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, USA, paper QM4E.3.
Y. Tian, Y.-K. Huang, S. Zhang, P. R. Prucnal, and T. Wang, “112-Gb/s DP-QPSK transmission over 7,860-km DMF using phase-conjugated copy and digital phase-sensitive boosting with enhanced noise and nonlinearity tolerance,” in Proc. Optical Fiber Communication (OFC) Conference, Anaheim, CA, USA, Mar. 2013, paper OTu2B.5.
B. J. Shastri, P. R. Prucnal, and D. V. Plant, “A 20-GSample/s (10 GHz × 2 clocks) burst-mode CDR based on injection-locking and space sampling for access networks,” in Proc. IEEE Photonics Conference (IPC), Burlingame, CA, USA, Sep. 2012, paper ThC.3, pp. 717–718.
A. N. Tait, M. A. Nahmias, M. P. Fok, and P. R. Prucnal. “A dual resonator enhanced asymmetric Mach-Zehnder: ultrafast passive thresholder for silicon-on-insulator,” in Proc. Optical MEMS and Nanophotonics Conference (OMN), Banff, AB, Canada, Aug. 2012, paper WP31, pp. 212–213.
- Paul Prucnal, Professor of Electrical Engineering
- Yue Tian, Graduate Student
- Alex Tait, Graduate Student
- Mitchell Nahmias, Graduate Student
- Bhavin Shastri, Post-doc
Nonlinear Optical Thresholding
Thresholders are the heart of analog-to-digital converters, comparators and operational amplifiers. Moreover, an all-optical thresholder even beats the limits of electronics and are thus useful in photonic applications such as neuromorphic photonics and optical code division multiple access (OCDMA). A thresholder can effectively boost the signal to noise ratio (SNR) of optical signals and improve the system performance in a variety of scenarios including telecommunications, fiber sensing and quantum communications. We are particularly interested in its use in enhancing contrast in weakly modulated optical signals.
Our approach exploits the nonlinear silicon photonic processes to carry out the signal processing. We have successfully demonstrated an all-optical programmable nonlinear thresholder on a silicon integrated circuit. Our device structure is based on Mach-Zehnder interferometer loaded with microrings. It can accommodate optical signals of different power levels and wavelengths. We have achieved a significant power contrast enhancement with our current device and are currently exploring novel device architectures to enhance the device bandwidth and reduce the power costs.
Fig Microscope image of all-optical thresholder on silicon chip
Fig: Contrast enhancement using our nonlinear optical thresholder