Invention Grant
- Patent Title: Subcarrier based adaptive equalization of electrical filtering effects on sub-carrier multiplexed signals
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Application No.: US16254552Application Date: 2019-01-22
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Publication No.: US11539447B2Publication Date: 2022-12-27
- Inventor: Ahmed Awadalla
- Applicant: Infinera Corporation
- Applicant Address: US CA Sunnyvale
- Assignee: Infinera Corporation
- Current Assignee: Infinera Corporation
- Current Assignee Address: US CA Sunnyvale
- Agent David L. Soltz
- Main IPC: H04J4/00
- IPC: H04J4/00 ; H04B10/69 ; H03H17/06

Abstract:
Consistent with the present disclosure, the above-described subcarrier noise, which may be characterized as a linear filtering effect, may be reduced or eliminated by providing a first multiple-input multiple output (MIMO) circuits at the transmit end of an optical link and providing a second MIMO circuit at the receive end of the optical link. The first MIMO may include a first plurality of filters, each of which may include a finite-impulse response (FIR) filter having variable coefficients or tap weights that may be changed or adapted to minimize subcarrier noise associated with the modulator, as well as D/A and analog circuitry, at the transmit end of the optical link. In addition, the second MIMO may include a second plurality of filters, each of which may also include an FIR filter having variable coefficients or tap weights that may be changed or adapted to minimized subcarrier noise associated with the optical hybrids, as well as A/D and analog circuitry, at the receive end of the optical link. In one example, a least means square (LMS) technique may be employed to calculate desired coefficients or tap weights whereby an error determined based on the signal detected at the receiver is minimized to update the coefficients of the FIR filters.
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