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Single sideband signals generated by micro-ring modulators were demonstrated for 80-km standard single-mode fiber transmission with Kramers-Kronig direct detection. The integrated transmitter with KK receiver is suitable for future low-cost, low-power and low-footprint datacenter interconnects.

In this paper, we report the first demonstration of using silicon photonic integrated circuits for 62 Gb/s 4-quadrature-amplitude-modulation (4-QAM) orthogonal frequency-division multiplexing (OFDM) and 112 Gb/s 16-QAM OFDM over an 80-km standard single-mode fiber (SSMF) transmission with the Kramers-Kronig (KK) direct detection. Single sideband optical signals are generated by two silicon micro-ring modulators, and directly detected by a single integrated germanium-on-silicon waveguide photodiode fabricated in a multi-project wafer run. The complex optical field can be fully re-constructed by KK detection after an 80-km SSMF transmission. The integrated transceivers with KK detection are suitable for future low-cost, low-power, and small-footprint data center interconnects in the short and medium reach.

We evaluate the performance of 112-Gb/s PAM-4 modulation using integrated Ge electro-absorption modulator operating at 1622 nm. Using pre-equalization with 25-GHz bandwidth limited arbitrary waveform generator we demonstrated 1-km fiber transmission at 112 Gb/s.

We measure the second order and third order spurious-free dynamic range (SFDR) of an integrated germanium Franz-Keldysh modulator and assess the performance of the modulator for discrete multi-tone (DMT) modulation without any pre-equalization.

We propose a compact and high-speed I/Q modulator based on two germanium-on-silicon Franz-Keldysh electro-absorption modulators. We demonstrate a 4-QAM signal transmission and reconstruct the complex signal in a Kramers-Kronig receiver for future datacenter interconnect applications.

Optical interconnect is a potential solution to attain the large bandwidth on-chip communications needed in high performance computers in a low power and low cost manner. Mode-division multiplexing (MDM) is an emerging technology that scales the capacity of a single wavelength carrier by the number of modes in a multimode waveguide, and is attractive as a cost-effective means for high bandwidth density on-chip communications. Advanced modulation formats with high spectral efficiency in MDM networks can further improve the data rates of the optical link. Here, we demonstrate an intra-chip MDM communications link employing advanced modulation formats with two waveguide modes. We demonstrate a compact single wavelength carrier link that is expected to support 2x100 Gb/s mode multiplexed capacity. The network comprised integrated microring modulators at the transmitter, mode multiplexers, multimode waveguide interconnect, mode demultiplexers and integrated germanium on silicon photodetectors. Each of the mode channels achieves 100 Gb/s line rate with 84 Gb/s net payload data rate at 7% overhead for hard-decision forward error correction (HD-FEC) in the OFDM/16-QAM signal transmission.

Distributed temperature sensing has been achieved by spatially resolved measurement of the probe time delay resulted from stimulated-Brillouin-scattering slow light. The temperature of a particular fiber section can be monitored by setting an appropriate relative delay between the pump and probe pulses. By controlling the relative delay, we have achieved distributed profiling of the temperature along the whole sensing fiber. This scheme provides an alternative way for distributed temperature sensing with the potential of real-time temperature monitoring. A relatively high-temperature resolution of 0.7 degrees C is obtained., QC 20140122