E. Grard

On the interest of chirped lasers for AMOOFDM transmissions in long distance PON networks

We report the performance of a chirped laser in IMDD-based transmissions and we show that the interplay between laser chirp and fiber dispersion can be very attractive for long distance PONs if adaptive OFDM modulation is used.

Analog microwave photonic link based on a high power directly modulated laser, a high power photodiode and passive impedance matching

We report on the design and characterization of a high-power and high dynamic range directly modulated analog fiber optic link in the S (2-4 GHz) band. The link is amplifier free, and uses passive impedance matching networks associated to high power laser diode and high power photodiode. Thanks to the high components efficiencies, together with the benefit of reactive impedance matchings, we achieved a high gain (≥ 0 dB) over 500 MHz bandwidths. Moreover, the use of high power and high linearity components allowed us to achieve simultaneously an output -1dB compression point higher than 20 dBm, and an output third order intercept point (OIP3) of more than 31 dBm. The measured spurious free dynamic range is as high as 114 dB.Hz2/3.

Optical Transimpedance Receiver for High Data Transmission in OFDM Modulation Format

This paper presents the design and performance of a single-ended transimpedance amplifier (TIA) for gigabit passive optical networks implementing orthogonal frequency division multiplexing modulation format. The circuit is realized using an industrial GaAs integrated technology. Low power consumption and small chip area are the main challenges in the TIA design. On-wafer characterization in terms of S-parameters, noise figure, gain compression, and intermodulation are presented and compared to simulated results showing a good agreement. The TIA is linked with a broadband PIN photodiode and introduced in a radio over fiber system. The optical link is simulated in a microwave software and characterized in terms of error vector magnitude by varying the radio frequency input power and the laser bias current.

Optical Transmission Performance for Directly Modulated Laser Considering Laser Chirp and Fiber Dispersion Using Adaptively Modulated Optical Orthogonal Frequency Division Multiplexing

Abstract Fiber dispersion coupled with the chirp parameter of the laser impacts the optical transmission system performance. Fiber dispersion causes the propagating pulses to spread and overlap, and the chirp produces a wavelength shift arising from the intensity variation of the laser. Coupled with the Levin-Campello bit-loading algorithm, adaptively modulated optical orthogonal frequency division multiplexing optimizes the data rate by taking into consideration the channel quality. This article shows the system performance for optical links starting with an optical back-to-back and ending with 125 km of single-mode fiber with a fixed optical budget of 30 dB for all distances.