Ciena Corporation

Iena Corporation

James St Leger Harley

Shahab Oveis Gharan

Tung Trong Nguyen

Michael Andrew Reimer

Timothy James Creasy

Christian Bourget

Blake Toplis

Kendal Zimmer

A method at a receiver comprises receiving a signal conveying symbols at respective positions within a clock cycle, the symbols comprising a data set consisting of data symbols and a pilot set consisting of pilot symbols; determining detected phases of the symbols based on the signal; generating first phase estimates based on the detected phases of a subset of the pilot set, and reference phases of the subset of the pilot set, the first phase estimates being associated with the positions of the pilot set; and generating second phase estimates based on the detected phases of the pilot set, reference phases of the pilot set, and the first phase estimates, the second phase estimates being associated with the positions of the pilot set and of at least a subset of the data set; and applying rotations to the detected phases of the symbols based on the second phase estimates.

Modular carrier recovery

A receiver generates a stream of digital samples from an analog electrical signal that represents data conveyed to the receiver over a communication channel, where the stream of digital samples comprises current samples corresponding to a current timepoint, previous samples corresponding to a timepoint earlier than the current timepoint, and subsequent samples corresponding to a timepoint later than the current timepoint. The receiver generates previous, current, and subsequent phase offset signals based on the previous, current, and subsequent samples, respectively. The receiver uses the previous phase offset signal to adjust clock frequency and clock phase of the current samples, thereby resulting in current adjusted samples. The receiver adjusts clock phase of the current adjusted samples based on any one of the previous, current, and subsequent phase offset signals. In some examples, receiver adjusts the clock phase of the current adjusted samples based on the subsequent phase offset signal.

Techniques for enhanced clock recovery

A method performed at a transmitter comprises generating a set of digital signals representing a constellation point, each dimension of the point being uniquely represented by m bits, where m&#x3f5;{1, 2, 3}; applying a linear polyphase filter to a digital signal of the set, the linear polyphase filter pre-compensating for a linear transfer function of an electro-optic path of the digital signal and generating a first filtered signal having a roll-off factor &#x3b1;, where &#x3b1; is a positive real number satisfying &#x3b1;&#x2264;1; applying a nonlinear polyphase filter to the digital signal, in parallel to applying the linear polyphase filter to the digital signal, the nonlinear polyphase filter generating a second filtered signal representing nonlinear noise in the electro-optic path; calculating a pre-compensated digital signal from a difference between the first and second filtered signals; and transmitting an optical signal based on the pre-compensated digital signal.

Low-power pre-compensation of linear and nonlinear transmitter effects in narrow-spectrum optical signals

A transmitter maps an N-bit sequence to a point selected from a four-dimensional (4D) constellation consisting of 2points which form a subset of a Cartesian product of first and second two-dimensional (2D) constellations, the first constellation consisting of M1 points divided into first, second, and third points, and the second constellation consisting of M2 points divided into fourth, fifth, and sixth points, wherein M1, M2&#x2265;5, and wherein log(M1&#xd7;M2)&#x3e;N. The subset includes any 4D point that is generated by combining any one of the M1 points and any one of the fourth points; includes any 4D point that is generated by combining any one of the first points and any one of M2 points; and excludes any 4D point that is generated by combining any third point and any sixth point. An optical signal representing the selected point is transmitted to a receiver.

Growing community of inventors

Richmond, CA, United States of America

James St Leger Harley