Designing an optical frequency comb generator for visible light communication applications

<p>The optical frequency comb generator (OFCG) is an efficient optoelectronic device that is included in many important applications over a various field such as microwave and optical communication. A novel scheme of OFCG presented in this work for visible light communication application based on amplitude modulation, radio frequency (RF) signal, phase shift and two Mach-Zehnder modulators (MZMs), our design features are simple with more efficient power and premium flatness of comb lines, the number of generating frequencies lines was 64 with a power stronger than -2 dBm over a 340 GHz bandwidth from a single continuous laser diode. Different chirping factor (α) of MZMs are implemented (3, 5, 7), as the results the best results related to α=5 with extra flatness, the system was designed and simulated by VPI design suite 9.8.</p>

Analysis of the Performance of a Coherent SAC-OCDMA-OFDM-DWDM System Using a Flat Optical Frequency Comb Generator for Multiservice Networks.

A SAC-OCDMA-OFDM-DWDM system using a flat optical frequency comb generator and a coherent communication system is proposed in this research. The objective is to develop a novel OCDMA communication system that is appropriate and dedicated to multiservice networks. A comparison between the two codes, EDW and RD, has been presented. It has been concluded that the RD code system has better performance in terms of robustness and number of users than the EDW code. By analyzing the BER for several symbol rates and comparing it to the pre-FEC threshold, the proposed system demonstrates its effectiveness against linear and nonlinear effects. Performance evaluation of the proposed system is carried out via co-simulation of OptiSystem and MATLAB.

Multi-wavelength 128 Gbit/s/λ PAM4 optical transmission enabled by a 100 GHz quantum dot mode-locked optical frequency comb

Semiconductor mode-locked lasers (MLLs) with extremely high repetition rates are promising optical frequency comb (OFC) sources for their usage as compact, high-efficiency, and low-cost light sources in high-speed dense wavelength-division multiplexing (DWDM) transmissions. The fully exploited conventional C- and L- bands require the research on O-band to fulfil the transmission capacity of the current photonic networks. In this work, we present a passive two-section InAs/InGaAs quantum-dot (QD) MLL-based OFC with a fundamental repetition rate of ~100 GHz operating at O-band wavelength range. The specially designed device favours the generation of nearly Fourier-transform-limited pulses in the entire test range by only pumping the gain section while with the absorber unbiased. The typical integrated relative intensity noise (RIN) of the whole spectrum and a single tone are -152 dB/Hz and -137 dB/Hz in the range of 100 MHz to 10 GHz, respectively. Back-to-back (B2B) data transmissions for 7 selected tones have been realised by employing a 64 Gbaud four-level pulse amplitude modulation format (PAM-4). The demonstrated performance shows the feasibility of the InAs QD MLLs as a simple structure, easy operation, and low power consumption OFC sources for high-speed fibre-optic communications.

All polarization-maintaining Er:fiber-based optical frequency comb for frequency comparison of optical clocks

In this research, we demonstrate an optical frequency comb (OFC) based on a turnkey mode-locked laser with a figure-9 structure and polarization-maintaining fibers for frequency comparison between optical clocks with wavelengths of 698 nm, 729 nm, 1068 nm and 1156 nm. We adopt a multi-branch approach in order to produce high power OFC signals at these specific wavelengths, enabling the signal-to-noise ratio of the beatnotes between the OFC and the clock lasers beyond 30 dB at a resolution bandwidth of 300 kHz. This approach makes the supercontinuum spectra generating process much easier in comparison to a single branch OFC; however, more out-of-loop fibers degrade the long term frequency instability due to thermal drift. To minimize the thermal drift effect, we set the fiber lengths of different branches to be similar, and we stabilize the temperature as well. The out-of-loop frequency instability of the OFC due to the incoherence of the multi-branch is about 5.5&#215;10-19 @ 4000 s, while the in-loop frequency instability of f ceo and that of f beat are 7.5&#215;10-18 @1 s and 8.5&#215;10-18 @1 s, respectively. The turnkey OFC meets the requirement of frequency comparison between the best optical clocks.