Evaluate optical oscillator in radio testbed

Important results from the project

The project met the established goal of testing an optical oscillator in a real radio testbed, allowing theoretical models to be compared with actual measurements to facilitate a good design flow. We realized that while phase noise in optical oscillators is low close to the carrier, the white noise floor can become excessively high due shot noise from photodetectors—considering signal power, biasing, etc. This is significant given that the end application operates in the electrical domain.

Expected long term effects

The fact that an optical oscillator presents both advantages and disadvantages regarding noise generation necessitates careful design if it is to be implemented in a product. While the technology offers integration benefits, it is currently not mature enough for use with existing component technologies; the optical laser technology required for this oscillator must be integrated with other chip technologies in the RF front-end to become competitive.

Approach and implementation

At the start of the project, relevant milestones were set in consultation with the examiner and supervisor. The work started with a literature study of an optical oscillator, then design supported by phase noise simulations, and verification of the generated signal using an actual radio, followed by an interpretation of the results. Before proceeding to the next stage, the results of the preceding stage were evaluated. Significant progress was observed at each stage, and the work proceeded.