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Directly modulated laser can be used as phase modulator due to chirp effect. However, accompanying amplitude modulation also results. By using EA Modulator in combination, light amplitude may be compensated enabling both amplitude and phase modulation of lightwave, which is an alternative method to conventional IQ modulator. Since light phase is proportional to intensity, we propose cumulative phasebalance...
We present a method to achieve vector modulation in an electroabsorption modulator with help of a directly modulated laser. We discuss the challenges involved and demonstrate the combined phase and amplitude modulation theoretically and experimentally using a commercial electroabsorption modulator integrated laser.
We investigate the feasibility of an electroabsorption modulator integrated laser as a digital coherent transmitter. The laser and EAM sections are used as phase and amplitude modulators respectively. We discuss the challenges involved and demonstrate the combined phase and amplitude modulation on a commercial device.
We demonstrate that our recently proposed chirp measurement technique can be applied to the measurement and visualization of the small-signal dynamic chirp characteristics of modulators in vector space for the first time. Both discrete modulators and those integrated in externally modulated laser modules can be characterized by this method. The results agree with existing method to the first order...
This paper demonstrates frequency response characterization of a directly modulated laser diode (bandwidth 2.5GHz) using a calibrated photodetector (bandwidth 15 GHz). This work complements our previous work in obtaining frequency response of both E/O and O/E components where only simple equipment setup is required. We discuss the issues affecting the accuracy. The results are compared with those...
We propose a novel method to measure chirp of an electro-absorption modulator in vector space due to intensity modulation at any frequency using optical homodyne quadrature demodulation technique. Chirp parameters are directly obtained in the small-signal vector space, enabling practical chirp assessment for advanced modulation optical transmission.
We propose a novel method to measure chirp of an electro-absorption modulator at any frequency using optical homodyne quadrature demodulation technique. Chirp parameters are directly obtained in the small-signal vector space, enabling practical chirp assessment for advanced modulation optical transmission.
We analyze the errors of a newly proposed measurement method on optoelectronic frequency response of photodiodes, which uses a high-extinction ratio Mach-Zehnder modulator to generate a two-tone stimulus lightwave. Five major error factors are identified and analyzed quantitatively. The result shows that the evaluated combined uncertainty is expected to be less than 0.5 dB.
We demonstrate frequency response measurement technique of photodiodes using standard Mach-Zehnder Modulator (MZM). The technique is based on heterodyne detection principle where two-tone light, whose frequency separation is in Microwave frequency range, is used to stimulate the photodiode. The MZM, with typical on-off extinction ratio of 30 dB in optical domain, is used to generate two-tone light,...
A Radio over Fiber uplink scheme is demonstrated experimentally where wireless signal is modulated on the same optical carrier as the existing optical Gigabit Ethernet link, taking advantage of prevalent Fiber to the Curb infrastructures. Without optical amplifier and filter, the received WLAN IEEE 802.11g signals show acceptable EVM up to 36 Mb/s over 8 km of fiber. The gigabit baseband signal does...
In this paper, a technique is proposed for measuring optical characteristics of an optical fiber coupler at multiple wavelengths simultaneously. The new system can be used in the manufacturing process of fused fiber couplers which helps reducing the optical characteristic measuring time and improving the performance monitoring ability over more wavelength regions. We have demonstrated a three-wavelength...
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