Gaël Kervella

Microwave Photonic Integrated Circuits for Millimeter-Wave Wireless Communications

This paper describes the advantages that the introduction of photonic integration technologies can bring to the development of photonic-enabled wireless communications systems operating in the millimeter wave frequency range. We present two approaches for the development of dual wavelength sources for heterodyne-based millimeter wave generation realized using active/passive photonic integration technology. One approach integrates monolithically two distributed feedback semiconductor lasers along with semiconductor optical amplifiers, wavelength combiners, electro-optic modulators and broad bandwidth photodiodes. The other uses a generic photonic integration platform, developing narrow linewidth dual wavelength lasers based on arrayed waveguide gratings. Moreover, data transmission over a wireless link at a carrier wave frequency above 100 GHz is presented, in which the two lasers are free-running, and the modulation is directly applied to the single photonic chip without the requirement of any additional component.

Integrated InP Heterodyne Millimeter Wave Transmitter

A monolithically integrated tunable heterodyne source designed for the generation and modulation of sub-terahertz signals is demonstrated. Distributed feedback lasers, semiconductor optical amplifier amplifiers, passive waveguides, beam combiners, electro-optic modulators, and high-speed photodetectors have been monolithically integrated on the same InP-based platform. Millimeter wave generation at up to 105 GHz based on heterodyning the optical tones from two integrated lasers in the integrated high bandwidth unitraveling-carrier photodetector has been demonstrated. This photonic integrated chip was used in a 100-Mb/s OOK wireless transmission experiment using the integrated amplitude modulator.

Optical injection locking of monolithically integrated photonic source for generation of high purity signals above 100 GHz

A monolithically integrated photonic source for tuneable mm-wave signal generation has been fabricated. The source consists of 14 active components, i.e. semiconductor lasers, amplifiers and photodetectors, all integrated on a 3 mm(2) InP chip. Heterodyne signals in the range between 85 GHz and 120 GHz with up to -10 dBm output power have been successfully generated. By optically injection locking the integrated lasers to an external optical comb source, high-spectral-purity signals at frequencies >100 GHz have been generated, with phase noise spectral density below -90 dBc/Hz being achieved at offsets from the carrier greater than 10 kHz.

Heterodyne millimeter wave source with monolithically integrated UTC photodiodes

A fully integrated tunable heterodyne source designed for the generation and modulation of sub-Terahertz signals is demonstrated. This device is to be used for high data-rate wireless transmissions. DFB lasers, SOA amplifiers, passive waveguides, beam combiners, electro-optic modulators and high speed photodetectors have been integrated on the same InP-based platform. Millimeter wave generation at up to 120 GHz based on heterodyning the optical tones from two integrated lasers in an also integrated high bandwidth photodetector has been demonstrated.

Photonic Integrated Circuits for Radio-Frequency Signal Generation

This paper reviews the current state of the art of photonic-enabled generation of radio-frequency signals with frequencies within the millimeter wave range (30 to 300 GHz) and above using photonic-integrated circuits (RF-PICs). One of the most important applications to date is the generation of carrier wave frequencies for ultrabroadband wireless communications systems, with data rates up to 100 Gb/s. Among the different photonic signal generation techniques that are available, we focus on the approaches for which photonic integrated solutions have been explored. Optical heterodyning is first presented, based on achieving the integration of a dual wavelength sources. The second approach is through onchip integrated mode locked lasers, with excellent performance in terms of frequency stable, low phase-noise narrow linewidth sources. We review the different laser structures that have been reported, to support the advantages of the new structures that we propose.

Wireless data transmission and frequency stabilization with a millimeter-wave photonic integrated circuit

We have developed and tested a photonic integrated circuit that contains DFB lasers, SOA amplifiers, passive waveguides, beam combiners, electro-optic modulators and high speed photodetectors. This device is used to generate a 90 GHz tone thanks to photomixing in the integrated photodiode of two optical tones. A wireless transmission of up to 1 Gbit/s with an open eye diagram is demonstrated. A solution to reduce the phase noise based on self-injection locking is demonstrated. It was used to lock the millimeter wave tone on its fifth sub-harmonic frequency resulting in a low phase noise, below -90 dBc/Hz at an offset frequency of 10 kHz.

Comparison of photonic integrated circuits for millimeter-wave signal generation between dual-wavelength sources for optical heterodyning and pulsed mode-locked lasers

A comparative study of two different Photonic Integrated Circuits (PICs) structures for continuous-wave generation of millimeter-wave (MMW) signals is presented, each using a different approach. One approach is optical heterodyning, using an integrated dual-wavelength laser source based on Arrayed Waveguide Grating. The other is based on ModeLocked Laser Diodes (MLLDs). A novel building block -Multimode Interference Reflectors (MIRs) – is used to integrate on-chip both structures, without need of cleaved facets to define the laser cavity. This fact enables us to locate any of these structures at any location within the photonic chip. As will be shown, the MLLD structure provides a simple source for low frequencies. Higher frequencies are easier to achieve by optical heterodyne. Both types of structures have been fabricated on a generic foundry in a commercial MPW PIC technology.

Photonic integrated circuit on InP for millimeter wave generation

Indium phosphide and associated epitaxially grown alloys is a material system of choice to make photonic integrated circuits for microwave to terahertz signal generation, processing and detection. Fabrication of laser emitters, high speed electro-optical modulators, passive waveguides and couplers, optical filters and high speed photodetectors is well mastered for discrete devices. But monolithic integration of them while maintaining good performances is a big challenge. We have demonstrated a fully integrated tunable heterodyne source designed for the generation and modulation of sub-Terahertz signals. This device is to be used for high data-rate wireless transmissions. DFB lasers, SOA amplifiers, passive waveguides, beam combiners, electro-optic modulators and high speed photodetectors have been integrated on the same InP-based platform. Millimeter wave generation at up to 120 GHz based on heterodyning the optical tones from two integrated lasers in an also integrated high bandwidth photodetector has been obtained.

Electrical injection locking of a fully integrated photonic integrated circuit based heterodyne source

We report the stabilization of a 5 GHz signal generated from a fully integrated heterodyne photonic source. The demonstration differs from previous work as it uses only optoelectronic elements integrated in the photonic circuit. We have mutually correlate the phase noise of each integrated DFB and we stabilize the RF beating on the external reference using frequency comb generation and cross injection locking.

Photonic-enabled millimeter-wave wireless data transmission links based on photonic integrated circuits

We present two different approaches for the generation of millimeter wave carrier signals for wireless data links based on photonic integrated circuits using the optical heterodyne technique. One approach, based on dedicated fabrication run, integrates all the required components on a single chip. A second approach is based on a multi-project wafer run on a generic integration platform. We demonstrate their application to wireless data transmission at 1 Gbps data rate without the requirement for phase stabilization schemes of the two wavelengths.