Dispersion-induced Carrier Suppression Effect Research Articles

Single passband microwave photonic filter using continuous-time impulse response

A single passband microwave photonic signal processor based on continuous time impulse response that has high resolution, multiple-taps and baseband-free response as well as exhibiting a square-top passband and tunability, is presented. The design and synthesis of the frequency response are based on a full systematic model for single passband microwave photonic filters to account for arbitrary spectrum slice shapes, which for the first time investigates the combined effects from both the dispersion-induced carrier suppression effect and the RF decay effect due to the spectrum slice width, to enable the optimum design to be realized by utilizing the carrier suppression effect to improve the filter performance. Experimental results demonstrate a high order microwave filter showing high resolution single passband filtering as well as exhibiting reconfiguration, square-top passband and tunability, for the first time to our best knowledge.

Combined optical amplification and dispersion compensation in radio over fibre links

The study presents theoretical and experimental investigations on radio over fibre links concerning the effect of fibre dispersion. An approach is presented to overcome the radio-frequency suppression effect in optical links based on the joint effect of semiconductor optical amplifier chirp, chromatic dispersion and non-linearities of optical fibre. The results show that the frequency notches caused by the dispersion induced carrier suppression effect may be sharply alleviated and the performance of the transmitted signal can be improved.

Compensation for dispersion-induced carrier suppression effect in microwave∕millimetre-wave optical links using optical phase conjugation in semiconductor optical amplifiers

Broadband compensation for the dispersion-induced carrier suppression effect in radio-over-fibre links is reported up to 40 GHz using a phase conjugator based on a semiconductor optical amplifier. The experimental results clearly show the feasibility of the optical phase conjugation technique to cancel the signal fading in a broad frequency range even in the presence of transmitter chirp. The system performance is ultimately set by the ASE noise levels introduced by the phase conjugator, which can be optimised by adjusting the pump power.

Frequency response of analogue optical links employing SOA-boosters

A theoretical model for the frequency response of analogue optical links employing semiconductor optical amplifier (SOA) boosters and dispersive and nonlinear single-mode fibres is reported, for the first time. This frequency response includes the effect of the negative chirp introduced by the SOA. Furthermore, the experimental results demonstrate that the dispersion-induced carrier suppression effect may be significantly alleviated by adjusting the amplifier input power and several device parameters.

Mitigation of chromatic dispersion effects employing electroabsorption modulator-based transmitters

In this letter, it is shown that the dispersion-induced carrier suppression effect in externally modulated 1550-nm analog fiber-optic links may be mitigated by properly adjusting the chirp parameter of an external electroabsorption modulator. It is theoretically modeled and experimentally demonstrated that a significant increase on the frequency-length product of fiber-optic links is achieved with this chirp-adjusting technique, when compared to traditional methods.

Chromatic dispersion effects in electro-optical up-converted millimetre-wave fibre optic links

Chromatic dispersion effects in upconverted millimetre-wave fibre optic links employing electro-optical modulators are investigated. It is shown that by biasing the electro-optical modulator at the the minimum transmission point, instead of biasing at the quadrature point, the dispersion-induced carrier suppression effect on the upconverted signal may be sharply mitigated, which results in an increased frequency-length product in millimetre-wave optical systems.