Optoelectronic recirculating delay line implementation of a high-q optoelectronic oscillator

A dual-loop optoelectronic oscillator incorporating an optoelectronic recirculating delay line in order to circumvent the limitations of optical coherence associated with all-optical loops is demonstrated. The optoelectronic oscillator produces a very stable signal at 5.4 GHz (suitable for WLAN 802.11n and 4G-WiMAX systems) with a sub-Hz 3-dB bandwidth and a Q-factor in excess of 10
¹⁰
. A phase noise of -115 dBc/Hz is recorded at 10 kHz offset, owing to the reduction in phase induced intensity noise, whilst side modes are significantly suppressed for offset values in the range 100 kHz - 1 MHz.