Observation of phase noise reduction in photonically synthesized sub-THz signals using a passively mode-locked laser diode and highly selective optical filtering

A Continuous Wave (CW) sub-THz photonic synthesis setup based on a single Passively Mode-Locked Laser Diode (PMLLD) acting as a monolithic Optical Frequency Comb Generator (OFCG) and highly selective optical filtering has been implemented to evaluate the phase noise performance of the generated sub-THz signals. The analysis of the synthesized sub-THz signals up to 120 GHz gives as a result an effective reduction of the electrical linewidth when compared to direct harmonic generation that begins at 50 GHz and becomes greater as the frequency increases. The phase noise reduction offered by the setup, along with its integration potential, cost and bandwidth, make it a promising candidate to the development of an integrated and high performance low phase noise local oscillator in the sub-THz range.Work supported by the Spanish Ministry of Science and Technology through the project TEC2009-14525-C02-02 and by the European Commission FP7 iPHOS Project. The work by A.R. Criado has been supported by the Spanish Ministry of Science and Technology under the FPI Program, Grant# BES2010-030290.Publicad

Coherent terahertz photonics

We present a review of recent developments in THz coherent systems based on photonic local oscillators. We show that such techniques can enable the creation of highly coherent, thus highly sensitive, systems for frequencies ranging from 100 GHz to 5 THz, within an energy efficient integrated platform. We suggest that such systems could enable the THz spectrum to realize its full applications potential. To demonstrate how photonics-enabled THz systems can be realized, we review the performance of key components, show recent demonstrations of integrated platforms, and give examples of applications

146-GHz millimeter-wave radio-over-fiber photonic wireless transmission system.

We report the experimental implementation of a wireless transmission system with a 146-GHz carrier frequency which is generated by optical heterodyning the two modes from a monolithically integrated quantum dash dual-DFB source. The monolithic structure of the device and the inherent low noise characteristics of quantum dash gain material allow us to demonstrate the transmission of a 1 Gbps ON-OFF keyed data signal with the two wavelengths in a free-running state at 146-GHz carrier wave frequency. The tuning range of the device fully covers the W-band (75 - 110 GHz) and the F-band (90 - 140 GHz)

80GHz balanced photodetector chip for next generation optical networks

We demonstrate a balanced 80GHz pin-photodetector chip with excellent responsivity, dark current and polarisation dependent loss. The device focuses on next generation optical networks with 56/64Gbaud and operates in C-band and L-band

Millimeter-wave signal generation by optical heterodyning two channels from an arrayed waveguide grating-based multi-wavelength laser

Arrayed waveguide grating multi-wavelength lasers have been shown to provide simultaneously multiple wavelengths. In this work we report the characteristics of the beat note in the millimeter-wave range. The optical linewidth measured from the modes generated by the different channels can be as narrow as 120 kHz. We present for the first time the beat note obtained from mixing two channels onto a high speed photodiode, demonstrating a narrow linewidth of 250 kHz, which is to the best of out knowledge the narrowest beat-note measured from a free running monolithic semiconductor dual wavelength source working on the 1.5 µm range

High-power and high-linearity photodetector modules for microwave photonic applications

We demonstrate hermetically packaged InGaAs/InP photodetector modules for high performance microwave photonic applications. The devices employ an advanced photodiode epitaxial layer known as the modified uni-traveling carrier photodiode (MUTC-PD) with superior performance in terms of output power and saturation. To further improve the thermal limitations, the MUTC-PDs were flip-chip bonded on high thermal conductivity substrates such as Aluminum Nitride (AlN) and Diamond. Modules using chips with active area diameters of 40, 28, and 20 μm were developed. The modules demonstrated a 3-dB bandwidth ranging from 17 GHz up to 30 GHz. In continuous wave mode of operation, very high RF output power was achieved with 25 dBm at 10 GHz, 22 dBm at 20 GHz, and 17 dBm at 30 GHz. In addition, the linearity of the modules was characterized by using the third order intercept point (OIP3) as a figure of merit. Very high values of OIP3 were obtained with 30 dBm at 10 GHz, 25 dBm at 20 GHz and more than 20 dBm at 30 GHz. Under short pulse illumination conditions and by selectively filtering the 10 GHz frequency component only, a saturated power of >21 dBm was also measured. A very low AM-to-PM conversion coefficient was measured, making the modules highly suitable for integration in photonic systems for ultralow phase noise RF signal generation.Efthymios Rouvalis, Frederick N. Baynes, Xiaojun Xie, Kejia Li, Qiugui Zhou, Franklyn Quinlan, Tara M. Fortier, Scott A. Diddams, Andreas G. Steffan, Andreas Beling and Joe C. Campbel

Millimeter-wave signal generation by optical heterodyning two channels from an arrayed waveguide grating-based multi-wavelength laser

Arrayed waveguide grating multi-wavelength lasers have been shown to provide simultaneously multiple wavelengths. In this work we report the characteristics of the beat note in the millimeter-wave range. The optical linewidth measured from the modes generated by the different channels can be as narrow as 120 kHz. We present for the first time the beat note obtained from mixing two channels onto a high speed photodiode, demonstrating a narrow linewidth of 250 kHz, which is to the best of out knowledge the narrowest beat-note measured from a free running monolithic semiconductor dual wavelength source working on the 1.5 µm range