Unequal channel spacing 8×5 Gbps optical system utilizing different signal representations.

Area of Science:

• Optical communications
• Signal processing

Background:

• Data representations significantly impact communication network performance, affecting capacity, bit rate, transmission distance, and impairments.
• Different data formats like non-return-to-zero (NRZ), chirped NRZ, duobinary, and duobinary return-to-zero (DRZ) influence signal integrity.

Purpose of the Study:

• To evaluate and compare the performance of NRZ, chirped NRZ, duobinary, and DRZ data representations.
• To analyze these representations in an eight-channel dense wavelength division multiplexing (DWDM) system for 5 Gbps data transmission over 250 km fiber.
• To assess performance under varying channel spacings and optical power levels.

Main Methods:

• Simulated an optical communication system using four data representations: NRZ, chirped NRZ, duobinary, and DRZ.
• Employed eight DWDM channels for transmitting data at 5 Gbps over a 250 km fiber length.
• Measured the quality factor under conditions of equal and unequal channel spacing, and across a range of optical power levels.

Main Results:

• For equal channel spacing, DRZ achieved a quality factor of 28.40 at 18 dBm, while chirped NRZ reached 26.06 at 12 dBm.
• For unequal channel spacing, DRZ yielded a quality factor of 25.76 at 17 dBm, and NRZ achieved 25.06 at 10 dBm.
• Performance varied significantly based on data representation, channel spacing, and optical power.

Conclusions:

• DRZ and chirped NRZ demonstrate superior performance in DWDM systems, particularly under specific channel spacing and power conditions.
• The choice of data representation is critical for optimizing long-haul fiber optic communication systems.
• Simulation results provide valuable insights for designing high-capacity optical networks.