Non-sweep DC component estimation method for a virtual-carrier assisted Kramers-Kronig receiver

Area of Science:

• Optical communications
• Signal processing
• Information theory

Background:

• Kramers-Kronig (KK) receivers recover signal phase from intensity, crucial for optical interconnections.
• High-speed KK systems often use AC-coupled photodetectors, which filter out the DC component.
• Loss of the DC component disrupts the KK algorithm, necessitating accurate digital recovery.

Purpose of the Study:

• To propose a novel non-sweep DC component estimation scheme for virtual-carrier (VC) assisted KK receivers.
• To enable accurate DC value recovery in the digital domain with reduced computational complexity.
• To improve the optical signal-to-noise ratio (OSNR) performance of high-speed optical interconnections.

Main Methods:

• Developed a non-sweep DC estimation scheme using the optimized digital carrier-to-signal power ratio (OD-CSPR) method.
• Employed a one-dimensional search optimization algorithm (golden section search and parabolic interpolation) for efficient estimation.
• Validated the method through simulations and experiments in VC-assisted KK receiver optical transmission scenarios.

Main Results:

• The OD-CSPR method accurately estimates the DC component with only 3-4 iterations.
• Accurate DC estimation was achieved across a wide range of carrier-to-signal power ratios (CSPR).
• The proposed method achieved OSNR gains of 0.9 dB (back-to-back) and 0.7 dB (80 km fiber transmission) at 160 Gb/s.

Conclusions:

• The proposed non-sweep OD-CSPR method offers an efficient and accurate solution for DC component estimation in VC-assisted KK receivers.
• This approach relaxes analog-to-digital converter (ADC) and electronic amplifier requirements.
• The method demonstrates significant OSNR improvements compared to conventional techniques, enhancing optical transmission performance.