Shaofeng Qiu

Regularized Sparse Recovery for Optical Power Monitoring With Low-Cost Tunable Optical Filters

We propose a regularized sparse recovery (RSR) technique to monitor optical power from the broadened optical spectrum acquired by scanning a tunable optical filter (TOF). The key idea of RSR is to find a smooth but sparse signal spectrum that matches the observed data of a broadened spectrum model within a tolerable error. Experiments demonstrated that RSR can be used to monitor accurately the power of mixed 10-G/40-G wavelength-division-multiplexing channels with 50-GHz channel spacing using commercial TOFs. This technique also has higher immunity to measurement and TOF response errors than the regularized least square method. It does not require strong repeatability of TOF response and makes the low-cost TOF suitable for optical power monitoring.

Green and agile petabit optical sub-wavelength switching prototype for the future OTN multi-chassis switch cluster

A proof-of-concept prototype of optical sub-wavelength switching fabric is demonstrated. The prototype supports petabit switching capacity with agile service granularity and low power consumption.

An optical burst switching fabric of multi-granularity for Petabits/s multi-chassis switches and routers

A multi-granularity optical burst switch fabric with 80M×80M(M=2, 4, 8...) ports using Fast Tunable Lasers and ULCF-AWG is proposed. This fabric for Petabits/s multi-chassis switches and routers is also experimentally demonstrated.

Close to 100 Gbps discrete multitone transmission over 100m of multimode fiber using a single transverse mode 850nm VCSEL

Discrete Multitone Transmission (DMT) transmission over standard multimode fiber (MMF) using high-speed single (SM) and multimode (MM) Vertical-Cavity Surface-Emitting Lasers (VCSELs) is studied. Transmission speed in the range of 72Gbps to 82Gbps over 300m -100m distances of OM4 fiber is realized, respectively, at Bit-Error-Ratio (BER) <5e-3 and the received optical power of only -5dBm. Such BER condition requires only 7% overhead for the conversion to error-free operation using single Bose-Chaudhuri-Hocquenghem forward error correction (BCH-FEC) coding and decoding. SM VCSEL is demonstrated to provide a much higher data transmission capacity over MMF. For 100m MMF transmission SM VCSEL allows 82Gbps as compared to MM VCSEL resulting in only 34Gbps at the same power (-5dBm). Furthermore, MM VCSEL link at 0dBm is still restricted at 100m distance by 63Gbps while SM VCSEL can exceed 100Gbps at such power levels. We believe that with further improvement in SM VCSELs and fiber coupling >100Gbps data transmission over >300m MMF distances at the BER levels matching the industry standards will become possible.

Coherent OTDR used for fibre faults detection

We have demonstrated a coherent OTDR based on log-detector. The effect of laser linewidth and electrical filter bandwidth on coherent OTDR performance is theoretically analyzed and experimentally investigated.