Xue Jun Meng

Improved intrinsic dynamic distortions in directly modulated semiconductor lasers by optical injection locking

The effects of optical injection locking on the nonlinear distortions of directly modulated semiconductor distributed feedback (DFB) lasers are investigated experimentally. The second harmonic distortion (SHD) and third harmonic distortion (THD), as well as the third-order intermodulation distortion (IMD3), are measured as functions of modulation frequency for both the free-running and injection-locked lasers. Under strong injection locking with -8-dB injection ratio, the SHD and THD of the DFB laser have been suppressed by 15 dB from 2 to 4 GHz. Moreover, nearly 15-dB reduction in IMD3 has been observed from 1.4 to 3.0 GHz with the same injection conditions. We also found that the injection locking is not effective in reducing the low-frequency distortions.

Demonstration of an analog fiber-optic link employing a directly modulated semiconductor laser with external light injection

We demonstrate an analog fiber-optic link employing a directly modulated semiconductor distributed-feedback (DFB) laser under optical injection locking. The results show that injection locking can significantly improve performances of analog fiber-optic systems at frequencies considerably beyond the bandwidth of free-running semiconductor lasers.

A "tandem" single sideband fiber-optic system using a dual-electrode Mach-Zehnder modulator

Summary form only given.Optical single sideband modulation has received great interest as a way to reduce the dispersion penalty of analog fiber-optic systems. We propose and demonstrate a tandem single sideband fiber-optic link, which uses a dual-electrode Mach-Zehnder modulator to place different information in each of the two sidebands, thus doubling the bandwidth efficiency.

Gain and bandwidth enhancement of directly modulated analog fiber optic links using injection-locked gain-coupled DFB lasers

We report on the experimental demonstration of directly modulated analog fiber optic links with gain-coupled DFB lasers under strong optical injection locking. Successful transmission of BPSK signals up to 18 GHz has been achieved.

Full optical spectral utilization by microwave domain filtering of tandem single sidebands

We present an optical tandem single sideband receiver that eliminates the need for guardbands between adjacent WDM channels, while also receiving signals that have different data on the two sidebands of the same optical carrier.

Suppression of intermodulation distortion in DFB lasers by external optical injection locking

We report on the experimental investigation of third-order intermodulation distortion in directly modulated distributed feedback (DFB) lasers under optical injection locking. Nearly 15 dB reduction in third-order intermodulation distortion has been observed from 1.4 to 3.0 GHz.

Modeling of an analog fiber-optic link with an injection-locked semiconductor laser

Summary form only given. Subcarrier-modulated (SCM) fiber-optic systems have applications in cable television distribution, and phased array antenna systems. The transmission capacity of the SCM system employing direct laser modulation is generally limited by the bandwidth of the semiconductor laser. Recently, several groups have proposed the use of strong injection-locking technique to enhance the modulation bandwidth. In this report, we present, to our knowledge, the first theoretical investigation of an analog optical fiber link using a directly-modulated semiconductor laser under strong injection-locking. The analysis is based on rate equations, which include phase and amplitude noises in both master and slave lasers.