Summary of the technology
High-Speed OFDM-Based Passive Optical Access Network
Project ID : 14-2010-2430
Description of the technology
Moshe Nazarathy, Department of Electrical Engineering, Technion
There is an increasingly growing interest in cost-effective technology to improve spectral efficiency of optical networks while allowing flexible bandwidth allocation between users. Wavelength Division Multiplexing (WDM) and Orthogonal Frequency Division Multiplexing (OFDM) play key role in many of the proposed solutions.
Existing time-domain based PON solutions share the medium and are limited in throughput. WDM solutions are also based on direct detection and applying OFDM requires complex wideband coherent optical detectors which are expensive and inappropriate for mass deployment. In addition, splitting a wideband OFDM signal to many users using a regular passive power splitter results in low power efficiency.
A novel system-wide concept, integrating WDM in the large scale with OFDM in a finer scale. Using a multi-band filter bank, the DS signal is split and associated to a group of ONUs or combined into an OFDM signal depending on the direction.
The use of field reconstruction techniques allows the ONU receiver to perform coherent detection without the need for a local oscillator. In particular this allows transmission of advanced modulation formats with high-spectral efficiency.
This novel signal/network architecture allows for multiple pilot tones to be transmitted simultaneously, and for multiple transmitters to modulate different pilot-tones, to be integrated into a single WDM channel, and detected as a single OFDM signal. Then, Integrated Optical Implementation of the ONU allows for low cost home premises equipment and enables high performance.
- Dramatically reduces the ONU sampling rate and complexity
- Increases power efficiency and prevents backscattering crosstalk
- Enables low cost home premises equipment at very high-performance, with flexible bandwidth allocation and many ONUs supported over long distances
- Allows for doubling the data-rate and free of polarization fading
- Enables the usage of low-bandwidth reception
- Transmission format and standards
- Optical access networks
- OFDM-based optical links