Wu Deming

High speed integrated acousto-optic switch with high extinction ratio

The technology of single phase unidirectional transducer and focused transducer was adopted for the design of acousto-optic switch. The extinction ratio up to 32 dB and switching speed at 300 ns was achieved.

A novel WDM-CDMA optical fiber communication system with asynchronous despreading technology

A WDM/CDMA optical fiber communication system with asynchronous despreading technology employing surface acoustic wave MSK match filter is reported. Key devices were designed and fabricated. The system can be used as a signaling network to manage other networks and can be evolved into a multi-stage multiplexing system.

Experimental study of the transient power overshoot in backward-pumped Raman amplified WDM systems

The channel distribution of the transient power overshoots, caused by the channels adding up, in backward pumped Raman amplified wavelength division multiplexed systems is studied experimentally. It is found that the time for the output power of different signal to drop from the maximum values to the minimum values is not equal to each other. The shorter the signal wavelength is, the smaller the time is. And the shape of the channel distribution of the maximal value of the power overshoot in the output signal is similar to that of the system ON-OFF gain distribution.

Application of spread spectrum technology at 64Mcps and 2Mbps as OAM signals in transparent optical networks

The application of wideband spread spectrum signal at standard 2.048Mbitls and 64Mchiph on the optical carrier for the transmission of operation, administration and maintenance signals has been developed and evaluated.

Principle analysis of IP wavelength router

Combining IP with WDM is an attractive direction for research. WDM will play an important role in IP network in future. Now, an urgent problem is how to introduce wavelength routing in an IP network. We solve this problem by designing IP wavelength router, implementing DPDP (default path and dedicated path) method. We prove the reasonableness and feasibility of this design by a principle experiment. A lot of problems related to this design are also discussed.

A novel hybrid acousto-electro-optic oscillator based upon SAW and fiber-optic communication technology

We demonstrate for the first time to our knowledge a new oscillator based upon SAW device and optical device. The unique characteristic of the hybrid acousto-electro-optic oscillator is that its overall oscillator loop can be longer than several hundreds kilometers, contrast remarkably to its pure electronics oscillator counterpart for only several millimeters or several centimeter long because that the loss in optical fiber is much less than that in electric cable.

The SPUDT technology for the design and fabrication of filters and switches in communication system

A large amount of work has been done to overcome the difficult problems of bidirectional loss for SAW transducer. It turns out that the design of single phase unidirectional transducer (SPUDT) is much more challenging then that of conventional interdigital transducers, because of the extreme difficulty to synthesize the optimum transduction tap and reflectivity weighting functions simultaneously. In this paper, electrode width controlled SPUDT is used for the fabrication of high efficient acousto-optic switch and low loss SAW filter used in fiber-optic communication.

The extensive experimental researches on AOTF in WDM system

With rapidly increasing demand for communication channels, wavelength division multiplexing (WDM) system are being deployed to expand the capacity. WDM systems require devices for the manipulation of multi-wavelength channels. Among these devices, the integrated acousto-optic tunable filter (AOTF) is rapidly gaining importance in the field of WDM communication systems because it has the combined features of rapid switching time, broad tuning range and parallel processing capability. The technology of hybrid unidirectional and focused transducer was adopted for the design of the AOTF. The AOTF consisted of a single-mode optical waveguide placed along the SAW propagation direction. Extensive researches areas, which were in optical add-drop multiplexers (OADM), gain equalization and optical switches, have been done.