Investigation on the equalization techniques for 10G-class optics enabled 25G-EPON

Area of Science:

• Optical Communications
• Digital Signal Processing
• Telecommunications Engineering

Background:

• Passive Optical Networks (PON) require capacity upgrades for higher speeds.
• Bandwidth-limited devices necessitate advanced equalization techniques for cost-effective solutions.
• 10G-class optics are prevalent, presenting an opportunity for leveraging existing infrastructure.

Purpose of the Study:

• To investigate equalization techniques for enabling 25 Gb/s transmission with 10G-class optics.
• To compare the performance of Feed-Forward Equalization (FFE) and Decision-Feedback Equalization (DFE) against Maximum Likelihood Sequence Estimation (MLSE).
• To analyze the analog-to-digital converter (ADC) parameter requirements for MLSE-based detectors.

Main Methods:

• Comparative analysis of FFE, DFE, and MLSE equalization techniques.
• Investigation of ADC sampling rate, resolution, and timing jitter for MLSE.
• Experimental validation of 25 Gb/s transmission using 10G-class Transceiver Optical Sub-Assembly (TOSA) and Receiver Optical Sub-Assembly (ROSA).

Main Results:

• 13-tap FFE and 3-tap DFE achieved performance comparable to MLSE.
• A 25-GS/s ADC with 4-bit resolution was sufficient for 25 Gb/s transmission.
• Achieved loss budgets of 28 dB in C-band and 30 dB in O-band.

Conclusions:

• 25 Gb/s transmission is achievable with 10G-class optics through effective equalization and appropriate ADC parameters.
• This approach offers a cost-effective strategy for upgrading PON capacity.
• The study demonstrates the feasibility of enhancing optical network performance without requiring entirely new hardware.