All-VCSEL based digital coherent detection link for multi Gbit/s WDM passive optical networks.

Area of Science:

• Optical Communications
• Photonics
• Digital Signal Processing

Background:

• Coherent optical communication systems offer high sensitivity and spectral efficiency.
• Vertical cavity surface emitting lasers (VCSELs) are cost-effective and compact light sources.
• Integrating VCSELs into coherent systems presents challenges in stability and performance.

Purpose of the Study:

• To demonstrate a fully digital coherent detection link utilizing VCSELs for both transmitter and local oscillator.
• To achieve high receiver sensitivity and long-haul transmission capabilities using low-cost VCSELs.
• To explore the potential of VCSEL-based coherent systems for passive optical networks.

Main Methods:

• Experimental setup of a digital coherent detection link using VCSELs at 1550 nm.
• Employing digital signal processing to compensate for frequency offset and chromatic dispersion.
• Testing transmission performance over 40 km of standard single-mode fiber.

Main Results:

• Achieved a data rate of 5 Gbps.
• Demonstrated a record receiver sensitivity of -36 dBm.
• Operated VCSELs without active cooling and enabled fully passive fiber transmission.
• Successfully compensated for frequency offset and chromatic dispersion using digital signal processing.

Conclusions:

• The proposed system showcases the viability of multi-gigabit coherent passive optical networks with extended reach.
• This work represents the first demonstration of coherent optical transmission using a low-cost VCSEL for both transmitter and local oscillator.
• VCSEL-based coherent systems offer a promising, cost-effective solution for future high-capacity optical networks.