Peigang Hu

Optical VPN in PON Using TDM-FDM signal format

We demonstrate a simple and low-cost PON with optical VPN functionality using a directly modulated laser diode to generate TDM-FDM format. This format enables that one tributary of the transmitted signal be reflected to ONUs in the same optical VPN.

A highly stable low-RIN hybrid Brillouin/erbium amplified laser source

We demonstrate a low-noise all-fiber hybrid Brillouin/erbium amplified source consisting of a Brillouin/erbium fiber laser with a subsequent Brillouin amplifier to boost the power and reduce the noise. The same single-mode fibers used in the fiber laser and the amplifier lead to the same amount of Stokes frequency shifts in spite of the environmental variation, ensuring stable Brillouin amplification. The hybridly amplified source features temperature insensitivity, low noise, potentially high power, and low cost. The relative intensity noise of the hybridly amplified source is /spl sim/10 dB lower than that of the erbium-doped fiber amplifier (EDFA)-based source at radio frequencies >200 MHz due to the filtering characteristics of the Brillouin amplification. Compared with an EDFA amplified fiber system, the spurious-free dynamic range of an analog transmission system employing such a laser source is improved by 7.7 dB owning to the lower RIN.

Generation of 16-Gb/s MSK signal using a single 10-GHz SSB modulator and simplified encoder/decoder

We propose a new scheme for generating optical MSK by using a commercial SSB modulator. The demodulation of the signal is based on a 2-bit delay MZI to simplify pre-coding/decoding circuits. This scheme is successfully demonstrated in a 16-Gb/s system.

Prototype demonstration of IP multicasting over optical networks with dynamic point-to-multipoint configuration

We demonstrate a novel overlay multicasting architecture: IP multicasting over optical networks with dynamic point-to-multipoint configuration. Experimental results show that the proposed architecture exhibits better performance than pure IP multicasting under heavy traffic load.

Precise in-band OSNR and spectrum monitoring using high-resolution swept coherent detection

We propose and demonstrate a novel in-band optical signal-to-noise-ratio (OSNR) and spectrum monitoring technique based on swept coherent detection. This technique measures the signal and the in-band amplified spontaneous emission spectra by properly adjusting the polarization states of the signal and the local oscillator. A high resolution of 0.002 nm is achieved. By integrating the detected spectra of the signal and the noise, the in-band OSNR can be obtained in a very precise manner. We monitor the OSNR values with high accuracy in the range of 10-30 dB.

Nonlinearity-tolerant in-band OSNR monitoring for synchronous traffic using gated-signal RF spectral analysis

We demonstrate a new in-band OSNR monitoring scheme using RF spectral analysis of gated framing-signal of synchronous traffic. The proposed technique is simple and robust to fiber-nonlinearity induced polarization rotation in WDM systems

A new grouped limited-wavelength-conversion optical cross-connect and its scalability performance

Scalability performance of optical node is an important issue in the design of optical cross-connect (OXC) architecture. A practical architecture is expected to be scalable easily with low cost. However, when OXC employed with wavelength converter (WC) to support virtual wavelength path (VWP), the OXC scalability degrade due to the limit number of the WCs and partial sharing characteristic. In this paper, we proposed a new scheme to expand a kind of limit wavelength conversion OXC, share-per-wavelength architecture, which shares the WC within the same wavelength. This scalable scheme is analyzed in detail through comparing various wavelength grouping methods. Furthermore, their blocking performance is studied by using discrete event simulation. The results of the simulation show that our scheme has comparable blocking performance to the architecture without scalability. The small improvement at high initial occupation is because small wavelength grouping lead to a little better sharing efficiency under high load. But when the group becomes too small, for example less than the number of WCs, the repeated WCs will reduce its performance.

Evaluation and experiment of a configuration algorithm for three-stage multi-granularity optical cross-connects

From element automatic control view, we propose a configuration algorithm for three-level cross-connects in data plane to handle with bypass, grooming and local add/drop traffic of fiber-level, band-level and wavelength-level by a abstract bipartite graph of MG-OXC and bandwidth utilization spectra graph. The configuration algorithm is evaluated by computer simulation as well as validated by experiment on our flexible Multi-functional Optical Switching Testbed (MOST).

An all-fiber low-noise hybrid erbium-Brillouin amplified laser source

We demonstrate a novel all-fiber hybrid erbium-Brillouin amplified laser source, and achieve 8-dB reduction of RIN compared with an EDFA based source. The resulting spurious-free dynamic range in an analog system is improved by 6.8 dB

A new routing enhancement scheme based on node blocking state advertisement in wavelength-routed WDM networks

The increasing switching capacity brings the optical node with considerable complexity. Due to the limitation in cost and technology, an optical node is often designed with partial switching capability and partial resource sharing. It means that the node is of blocking to some extent, for example multi-granularity switching node, which in fact is a structure using pass wavelength to reduce the dimension of OXC, and partial sharing wavelength converter (WC) OXC. It is conceivable that these blocking nodes will have great effects on the problem of routing and wavelength assignment. Some previous works studied the blocking case, partial WC OXC, using complicated wavelength assignment algorithm. But the complexities of these schemes decide them to be not in practice in real networks. In this paper, we propose a new scheme based on the node blocking state advertisement to reduce the retry or rerouting probability and improve the efficiency of routing in the networks with blocking nodes. In the scheme, node blocking state are advertised to the other nodes in networks, which will be used for subsequent route calculation to find a path with lowest blocking probability. The performance of the scheme is evaluated using discrete event model in 14-node NSFNET, all the nodes of which employ a kind of partial sharing WC OXC structure. In the simulation, a simple First-Fit wavelength assignment algorithm is used. The simulation results demonstrate that the new scheme considerably reduces the retry or rerouting probability in routing process.