Importance

Loading Importance Indicators...

Abstract

An integrated multi-wavelength transmitter, particularly useful in a wavelength-division multiplexed optical communications system. An arrayed waveguide grating has feedback channels between two coupling regions and is constructed such that, at each coupling region, one port carries all the optical signals of differing wavelengths while a set of other ports carry wavelength-separated signals. The multi-wavelength signal from a first coupling region is reflected from a mirrored surface back into the first coupling region and the arrayed waveguide grating, the mirrored surface thus forming one end of an optical cavity. Similar elements are arranged between corresponding single-wavelength ports of the two regions. The channel from the second coupling region is split into two parts. One part is passed through an optical gain region and is reflected back from the mirrored surface through the power splitter, now acting as a combiner. This reflection from the mirrored surface forms the second end of the optical cavity containing the gain region and provides laser operation at a single wavelength. The second part of the single-wavelength laser power from the second coupling region passes through an optical modulator and then enters wavelength-separated ports of the first coupling region. The modulator impresses a data signal upon the optical wave at the wavelength corresponding to the two ports of the two coupling regions. The arrayed waveguide grating and the second coupling region combine to transmit this single-wavelength signal with the impressed data signal to the output port carrying multiple wavelength signals. The multi-wavelength signal from the second coupling region is the output of the transmitter and contains the modulated carriers for all wavelengths. Such a transmitter is usefully applied to a wavelength-division multiplexing (WDM) fiber communication system.

Loading the Abstract Image...

First Claim