Xiaobo Xie

Linearized Mach-Zehnder intensity modulator

A novel configuration of electrooptic intensity modulator based on a Mach-Zehnder interferometer with ring resonators coupled to each arm is proposed and analyzed theoretically. It is shown that this configuration offers a large improvement in modulation linearity with no requirements for complicated and precise electrical control.

Ring-assisted frequency discriminator with improved linearity

A frequency discriminator combining a Mach-Zehnder interferometer with ring resonators is proposed, analyzed and shown to offer a large improvement in linearity without any significant reduction in bandwidth. This can improve the performance of analog optical links by canceling the intermodulation distortion.

Compact linearized optical FM discriminator

A new type of optical frequency discriminator is proposed and analyzed numerically. The discriminator is based on a linear variation of the reflectivity of an optical reflection grating versus frequency. The proposed chirped grating has a constant /spl kappa/ or index variation and the reflectivity versus optical frequency is tailored by employing a grating with a spatially varying chirp parameter. Integration with a frequency-modulated distributed feedback laser would yield an efficient photonic RF transmitter.

A model for optimization of the performance of frequency-Modulated DFB semiconductor laser

We have developed a model of frequency modulated distributed feedback laser with intracavity phase modulator and have shown that it can operate in two different regimes, only one of which has good frequency-modulated (FM) response. We have identified the combination of the laser parameters that forces laser to operate in high FM efficiency regime. The results of our initial experiments support these conclusions.

Suppression of spurious intensity modulation in frequency-modulated semiconductor lasers

It is shown theoretically that spurious intensity modulation afflicting most frequency-modulated semiconductor lasers can be effectively suppressed by proper design of the cavity incorporating distributed Bragg mirror and modulator section.

Optimization of the performance of frequency-modulated DFB semiconductor laser: theory and experiment

We have developed a model of frequency modulated DFB laser with intra-cavity phase modulator and identified the combination of parameters leading to high FM efficiency. The results of our initial experiments support these conclusions.

Linear optical frequency discriminator

Summary from only given. We have proposed and analyzed a novel FM discriminator that is simple and lends itself to integration. It is shown that a potential 7 dB improvement in the dynamic range can be attained without paying a bandwidth penalty. The proposed device, consists of an unbalanced Mach Zehnder interferometer with ring resonators coupled to each of its arm.