Case Western Reserve University

Harmonic Lightwaves, Inc.

Xingyu Zou

Alan C Nilsson

David Piehler

Chien-Yu Kuo

Shouhua Huang

Kai-Ming Feng

David Arthur Smith

Alan E Wilner

Jin-Xin Cai

A dynamic power equalization module ( ) for an optical network is provided. It includes a module input ( ) for receiving an optical transmission ( ) containing a combination of different channels (C -C ). Each channel (C -C ) has a different characteristic wavelength (&lgr; -&lgr; ) and different varying power. A power equalization device that is polarization insensitive is connected between the module input ( ) and a module output ( ). The power equalization device is driven by RF acoustic signals ( ). A feedback loop ( ) receives at least a portion of output from the module output ( ) and generates, based upon a comparison of relative powers of the different channels (C -C ), the RF acoustic signals ( ) which drive the power equalization device. The power equalization device is driven such that it dynamically controls transmission of the different channels (C -C ) to substantially equalize power differentials therebetween. The power equalization device includes a parallel array of acousto-optic modulators (AO -AO ).

Dynamic power equalization of many wavelength-division-multiplexed channels in a fiber-optic system

A wavelength division multiplexer (WDM) in an optical fiber transmission system launches analog signals, for instance a multi-channel television signal. The WDM enhances signal quality by transmitting along a single fiber two different optical wavelength signals, each carrying identical RF information. This results in a 3 dB improvement in carrier to noise ratio. The WDM combines two or more wavelengths centered around for instance 1550 nm or 1310 nm. A typical difference between the two wavelengths is 3 nm. In other embodiments, more than two wavelengths are used. The receiver is for instance a single photosensitive element. The phase of the two RF signals is adjusted in the optical or RF domain to be the same upon arrival at the receiver. In other embodiments, the receiver includes two photosensitive elements, each receiving from a receiver end WDM a single wavelength. In this case, the phase adjustment may be applied at the receiver in the optical or RF domain.

Optical communications system with wavelength division multiplexing

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San Jose, CA, United States of America

Xingyu Zou