Electroabsorption modulator integrated distributed feedback laser transmitter
AssigneeAgere Systems Guardian Corp.
InventorsLaurens Bakker, Naresh Chand, Doutje Tjitske van Veen
Life of this patent
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Abstract
An optical transmitter for digitally modulated RF sub-carriers comprising an electroabsorption modulator integrated distributed feedback laser for transmitting the digitally modulated RF sub-carriers in the sub-octave frequency range. The negative bias is optimized for maximum carrier signal to noise ratio (CNR) which occurs when the composite triple beat (CTB) non-linear distortion is minimum that allows higher modulation index without causing any in-band distortion. A higher CNR increases the receiver sensitivity and thus more users can be served from a single transmitter or the transmitting signal can be modulated with higher order of digital modulation.
Claims12
A optical transmitter for digitally modulated RF sub-carriers comprising:
- an electroabsorption modulator integrated distributed feedback laser having an electroabsorption modulator section adapted for transmitting the digitally modulated RF sub-carriers in the sub-octave range;
- and
- a circuit configured for applying a negative bias to the electroabsorption modulator integrated distributed feedback laser;
- wherein the negative bias is selected to increase modulation index of the electroabsorption modulator section of the electroabsorption modulator integrated distributed feedback laser above a modulation index of an electroabsorption modulator section of an electroabsorption modulator integrated distributed feedback laser having a zero bias, without causing in-band non-linear distortion.
A system for optical transmission of digitally modulated RF sub-carriers comprising:
- an electroabsorption modulator integrated distributed feedback laser;
- a modulation circuit configured for coupling the digitally modulated RF sub-carriers in the sub-octave frequency range to an electroabsorption modulator section of the electroabsorption modulator integrated distributed feedback laser;
- and,
- a circuit for applying a negative bias to the electroabsorption modulator section;
- wherein the negative bias is selected to increase modulation index of the electroabsorption modulator section of the electroabsorption modulator integrated distributed feedback laser above a modulation index of an electroabsorption modulator section of an electroabsorption modulator integrated distributed feedback laser having a zero bias, without causing in-band non-linear distortion.
A method for optical transmission of digitally modulated RF sub-carriers comprising the following steps:
- modulating an electroabsorption modulator section of an electroabsorption modulator integrated distributed feedback laser with the digitally modulated RF sub-carriers in the sub-octave range;
- applying a negative bias to the electroabsorption modulator section;
- wherein the negative bias is selected to increase modulation index of the electroabsorption modulator section of the electroabsorption modulator integrated distributed feedback laser above a modulation index of an electroabsorption modulator section of an electroabsorption modulator integrated distributed feedback laser having a zero bias, without causing in-band non-linear distortion.
Dependencies are inferred from the claim text.