Digital optical modulator for programmable n-quadrature amplitude modulation generation

摘要

An optical transceiver comprising an optical signal input, a first modulation section coupled to the optical signal input, a second modulation section coupled to the optical signal input and positioned in serial with the first modulation section, wherein the first modulation section comprises a first digital electrical signal input, a first digital driver coupled to the first digital electrical signal input, and a first modulator coupled to the first digital driver, and wherein the second modulation section comprises a second digital electrical signal input, a second digital driver coupled to the second digital electrical signal input, and a second modulator coupled to the second digital driver, and an optical signal output coupled to the first modulation section and the second modulation section.

主权项

1. An apparatus comprising:
digital electrical signal inputs; an optical signal input; digital drivers, wherein each of the digital drivers is coupled to one of the digital electrical signal inputs; a modulator coupled to the optical signal input and the digital drivers, wherein the modulator comprises N segments, where N is an integer, and wherein the modulator is configured to generate a n-quadrature amplitude modulated (nQAM) signal; and a delay circuit positioned between at least one of the digital electrical signal inputs and at least one of the digital drivers, wherein the delay circuit is configured to substantially match a phase of the optical signal input to a phase of the digital electrical signal inputs, wherein n indicates a desired level of modulation of the nQAM signal, wherein a quantity of the N segments is based on the desired level of modulation of the nQAM signal, wherein there is no digital-to-analog converter positioned between the digital electrical signal inputs and the modulator, wherein the quantity of the N segments is determined according to N=(n0.5)−1 when each of the N segments is coupled to only one digital driver, and wherein the digital drivers consist of a plurality of logical inverters arranged substantially in parallel with each other.