We propose a novel multiple pilot-carriers assisted direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) superchannel transmission scheme. With the proposed scheme, a 432-Gb/s transmission over 3040-km standard single mode fiber (SSMF) is successfully demonstrated. The nonlinear effect of correlated/uncorrelated sub-band loading is also investigated.

We demonstrate a novel long-reach PON downstream scheme based on the regenerated pilot assisted direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) superchannel transmission. We use the optical comb source to form DDO-OFDM superchannel, and reserve the center carrier as a seed pilot. The seed pilot is further tracked and reused to generate multiple optical carriers at the local exchange. Each regenerated pilot carrier is selected to beat with an adjacent OFDM sub-band at ONU, so that the electrical bandwidth limitation can be much released compared to the conventional DDO-OFDM superchannel detection. With the proposed proof-of-concept architecture, we experimentally demonstrated a 116.7 Gb/s superchannel OFDM-PON system with transmission reach of 100 km, and 1:64 splitting ratio. We analyze the impact of carrier-to-sideband power ratio (CSPR) on system performance. The experiment result shows that, 5 dB power margin is still remained at ONU using such technique.

In this paper, a signal-to-signal beating interference (SSBI) cancellation technique is proposed in direct detection transmission system based on balanced photodiodes (BPDs). We use pilot-supported single-sideband direct detection scheme to transmit up to 400-Gb/s signal in three branches through a 10-km 7-core fiber. Using the manner of transmitting the signal in one core and the combination of signal and pilot in another core, the SSBI terms can be efficiently mitigated in both 100-Gb/s and 400-Gb/s direct detection optical orthogonal frequency division multiplexing (OFDM) transmission systems. Compared to the conventional pilot-supported direct detection scheme, no guard band is required based on our proposed SSBI elimination technique. The efficiency of the receiver’s bandwidth is significantly enhanced.

A smart cushion based on SFS (single-mode-few-mode-single-mode) structure is proposed and experimentally demonstrated, which can be applied in physiological and activity states monitoring simultaneously. The sensing unit embedded in a common cushion is designed as a sandwich structure, consisting of a piece of fiberglass mesh, a SFS structure layer and a polyvinyl chloride (PVC) layer thus the sensitivity can be significantly enhanced. With off-line processing and analyzing of the raw signals collected from the cushion system, the heartbeat rate (HR) and respiratory rate (RR) can be obtained with the maximum error of 1 bpm and the activity states on the cushion can be clearly distinguished within the accuracy of one second. Such a smart cushion has the advantages of low cost, compact structure and high comfort, especially suitable for office workers and the elderly in nursing homes.

A real-time non-wearable respiratory monitoring system based on single-mode-fiber-multimode-fiber-single-mode-fiber (SMS) with core-offset splicing is demonstrated and experimentally validated. Both the inhalation and exhalation activities can be detected within a wide respiratory frequency range.

With the development of coherent optical communication systems, the optical communication networks are becoming more dynamic and complex. The optical signals in communication networks are vulnerable to various impairments. Therefore, optical performance monitoring (OPM) is essential for optical networks, which ensures the robustness of the networks. Real-time chromatic dispersion (CD) monitoring is the basis for the compensation of CD induced transmission impairment. Therefore, to enable the high quality-of-service of reliable optical networks, it is essential to implement accurate CD monitoring for fiber optical transmission link. In this paper, we present a blind CD estimation method in conjunction with artificial neural network (ANN) for polarization division multiplexing (PDM) coherent optical communication systems. The CD monitoring range is set from 1340ps/nm to 9380ps/nm with step of 1340ps/nm. We experimentally demonstrate the proposed method in PDM quadrature phase-shift keying (QPSK), PDM 16 quadrature amplitude modulation (16-QAM) and PDM 64-QAM systems. The experiment results in our scheme show that CD values can be estimated successfully. The root-mean-square errors (RMSEs) of CD monitoring for 112Gbps PDM QPSK, 112Gbps PDM 16-QAM and 120Gbps PDM 64-QAM are 3.79ps/nm, 7.57ps/nm and 9.68ps/nm respectively.