We describe and compare in this paper two common methods to measure the half-wave voltage (Vpi) of an electro-optical modulator versus RF frequency of the driving electronic signal. We detail the required calibration procedures when necessary and demonstrate the methods experimentally from 100MHz up to 40GHz. Guidelines are finally given to select the most appropriate method depending on the application and modulator characteristics.

In this study, we present a lead-free, piezoelectric energy harvester capable of generating power in the milliwatt range. The harvester consists of four layers of polyvinylidene difluoride piezoelectric polymer, bonded to a cantilever with a tip mass. The cantilever’s resonance frequency was measured at 13.4 Hz. The piezoelectric layers are connected in parallel, resulting in a total capacitance of 27 nF. At resonance, under open-circuit conditions, the harvester generates nearly 90 Vpp when subjected to an acceleration of 1 g. When impedance is matched, the maximum power output reaches 2.4 mW. In addition, we integrated the harvester with commercially available signal conditioning cards, enabling conversion from an AC signal to a steady 3.3 V DC signal useful for electronics to evaluate their efficiency in charging a capacitor. Finally, we demonstrated the harvester’s functionality in an autonomous system that measures and displays temperature on a digital screen. The system operated autonomously for 6.5 h.

We demonstrate a monostatic LiDAR based on an InP photonic integrated optical phased array (OPA). The system utilizes an OPA with on-chip amplification which transmits and receives light simultaneously through an array of eight end-fire waveguide antennas. The OPA is capable of a 4.6 degrees angular resolution and a 41 degrees field of view. The on-chip amplifiers provide up to 21.5dB gain in a 1465-1600nm wavelength range. We show proof-of-principle FMCW (frequency modulated continuous wave) sensing through the monostatic OPA. The system relies on the frequency modulation with up to 10GHz frequency excursion of an external optically isolated DFB laser, which allows the simultaneous detection of range and velocity. The measurements were performed with a reflective target located similar to 2m away from the OPA, by varying the target position and velocity of 30 cm and +/- 5cm/s respectively. To the best of our knowledge, we demonstrated the first monostatic FMCW LiDAR implementation on an integrated InP OPA.

We present an experimental characterization of a thin film lithium niobate photonic integrated circuit (PIC) for a multimode free space optical communication receiver. The PIC coherently combines up to eight optical single mode signals with low insertion and propagation losses.

The use of millimeter-wave (mm-wave) frequencies is required in order to support the increasing number of connected devices expected from the fifth generation (5G) of mobile communications. Subsequently, the generation of radio-frequency (RF) carriers ranging from 10 GHz to 300 GHz and their transport through optical distribution network (ODN) is a key element of the future 5G fronthaul. Optically assisted RF carrier generation is one of the most promising solutions to tackle this issue, allowing a wide use of analog radio-over-fiber (ARoF) architectures. However the main limitation of these optical methods is related to the finite coherence of lasers sources, which can dramatically degrade data transmission in analog formats. To mitigate its impact, the use of orthogonal frequency-division multiplexing (OFDM) as the 5G standard allows employing efficient phase noise compensation algorithms. Therefore, in this study, we present an experimental demonstration of a mm-wave generation technique based on an optical phase-locked loop (OPLL) that fulfills the frequency specifications for 5G. Then, an algorithm is introduced that improves data recovery at reception and reduces the impact of a possible high phase noise carrier. Finally, a back-to-back data transmission experiment is performed, demonstrating the efficiency of the algorithm to reach the 5G requirements. These results emphasize the use of OPLLs as a viable solution to generate mm-wave carriers for 5G and beyond.

A resonant fiber ring cavity based on a photonic-bandgap hollow-core fiber is described and characterized. We explore the fine spectral dependence of the transmission losses of this cavity and their impact on the performances of the resulting resonator fiber optic gyroscope (RFOG).

We report an original technique for reducing the residual amplitude modulation in a resonator fiber optic gyroscope using fibered components. We illustrate its effectiveness and compare it to the classical method used to control the RAM by checking the photodiode signal spectrum and measuring the free spectral range of the cavity with both methods.

In a resonator fiber optic gyroscope (RFOG), a residual amplitude modulation (RAM) may appear with the light phase modulation used to generate the error signals, which are necessary for locking the frequency of the laser on the optical cavity resonance and measure the angular velocity. The RAM causes an unstable bias on the resonance frequency measurement and thus limits the gyro performances. A well-known method to suppress the RAM was introduced by Wong and Hall in 1985. The intensity of the modulated beam is monitored, before entering the resonator, to generate a continuous voltage controlling the natural birefringence of the modulator crystal. We show that this technique seems to be not adapted to setup with an imperfect polarizer (having a limited extinction ratio) at the output of phase modulator followed by component exhibiting polarization dependent losses. To counter this limit, we propose a new strategy and we illustrate its effectiveness with two types of phase modulator to probe a cavity resonance in transmission and reflection.

By combining the requirements on the angular random walk and the bias stability of an optical passive resonant gyroscope, we end up with simple expressions of its minimum diameter and the maximum power it should be probed with. These design parameters depend only on the propagation losses, the mode size and the Kerr properties of the cavity material. We applied these results to passive miniature resonant optical gyroscope based on state-of-the-art performances of photonic integrated circuit and whispering gallery mode technologies. We show that tactical grade gyroscope performances can be achieved with a diameter of a few cm provided the detrimental influence of the Kerr effect is mitigated using, for instance, an active control of the unbalance in the intensities. We further extend the analysis to medium performance gyroscope and give some hints on the efforts to be made to potentially demonstrate a miniature resonant optical gyroscope with this level of performance.

This paper presents an experimental demonstration of analog radio-over-fiber (ARoF) fronthaul for high-bandwidth, high-capacity millimeter wave (mm-wave) extended fifth generation mobile network (5G) new radio (NR) signals over an optical distribution network with optical space division multiplexing (SDM). ARoF is shown to alleviate fronthaul capacity bottlenecks, transporting an 800 MHz wide extended 5G NR signal and allowing to maintain full centralization in a centralized radio access network (C-RAN). The proposed ARoF fronthaul architecture features a transmitter that generates the ARoF signal and an optical signal carrying a reference local oscillator (LO) employed for downconversion at the remote unit (RU) from a single radio frequency (RF) reference at the central office (CO). An SDM based RAN with 7-core multi-core fiber (MCF) allows parallel transport of the uplink ARoF signal and reference LO at the same wavelength over separate cores. Transmission of an 800 MHz wide extended 5G NR fronthaul signal over 7-core MCF is shown with full real-time processing, achieving 1.4 Gbit/s with BER<3.8 × 10 −3 and thus below the limit for hard-decision forward error correction (FEC) with 7 % overhead. Downconversion at the RU is performed electrically with the remote-fed LO provided by the CO.

When locking the frequency of a laser to an optical cavity resonance, the residual amplitude modulation (RAM), which accompanies the phase modulation necessary to build the error signal, is a major limitation to the frequency stability. We show that the popular method demonstrated by Wong and Hall to cancel this effect, based on the measurement of the RAM using an auxiliary detector, is limited in the case of optical setups exhibiting polarization dependent losses and an imperfect polarizer at the modulator output, such as guided-wave optical systems.We propose and demonstrate a new method, using a single photodetector, to generate the two error signals and demonstrate its usefulness in the case of fibered systems.

The introduction of millimeter wave (mm-wave) frequency bands for cellular communicationswith significantly larger bandwidths compared to their sub-6 GHz counterparts, the resulting densification of network deployments and the introduction of antenna arrays with beamforming result in major increases in fronthaul capacity required for 5G networks. As a result, a radical re-design of the radio access network is required since traditional fronthaul technologies are not scaleable. In this article the use of analog radio-over-fiber (ARoF) is proposed and demonstrated as a viable alternative which, combined with space division multiplexing in the optical distribution network as well as photonic integration of the required transceivers, shows a path to a scaleable fronthaul solution for 5G. The trade-off between digitized and analog fronthaul is discussed and the ARoF architecture proposed by blueSPACE is introduced. Two options for the generation of ARoF two-tone signals for mm-wave generation via optical heterodyning are discussed in detail, including designs for the implementation in photonic integrated circuits as well as measurements of their phase noise performance. The proposed photonic integrated circuit designs include the use of both InP and SiN platforms for ARoF signal generation and optical beamforming respectively, proposing a joint design that allows for true multi-beam transmission from a single antenna array. Phase noise measurements based on laboratory implementations of ARoF generation based on a Mach-Zehnder modulator with suppressed carrier and with an optical phase-locked loop are presented and the suitability of these transmitters is evaluated though phase noise simulations. Finally, the viability of the proposed ARoF fronthaul architecture for the transport of high-bandwidth mm-wave 5G signals is proven with the successful implementation of a real-time transmission link based on an ARoF baseband unit with full real-time processing of extended 5Gnew radio signals with 800MHzbandwidth, achieving transmission over 10 kmof 7-core single-mode multi-core fiber and 9 m mm-wave wireless at 25.5 GHz with bit error rates below the limit for a 7% overhead hard decision forward error correction.

The generation of tunable RF signals at high frequencies (> GHz) with low phase noise is crucial for telecommunication systems, broadband analog-to-digital conversions and RADAR systems. Recently, Frequency-Shifted Feedback (FSF) cavities seeded by a CW laser' so-called Talbot lasers' have been proposed to generate pulse trains with a repetition rate adjustable over orders of magnitude (up to tens of GHz), while being based on a low frequency RF synthesizer [1]. However, as such, due to the detrimental effects of amplified spontaneous emission, the phase noise performances of Talbot lasers are relatively poor. Here, we introduce a Talbot laser with a RF feedback inspired by coupled optoelectronic oscillators [2]. The regenerative RF loop allows operating the Talbot laser beyond threshold, by modulating the losses inside the optical cavity at the Talbot frequency. The purity of the generated signal is greatly improved, while preserving the FSF broad tuning capability at high frequency.

We propose and demonstrate an improved Talbot laser including a regenerative RF feedback loop. This architecture greatly enhances both amplitude and noise performances of the pulsed laser, while preserving the broadband tunability of its repetition rate. The phase noise power spectral density of the associated RF signal is found to be independent of the repetition rate. For a 4.9 GHz repetition rate, the timing jitter is as low as 54 fs (integrated between 10 kHz and 100 MHz offset frequency). This architecture paves the way towards tunable high performances coupled opto-electronic microwave oscillators.

The dynamic spray-gun deposition method was developed in 2006 to fabricate field effect transistors based on random arrays of carbon nanotubes (CNTs) field effect transistors for gas sensing applications. Thanks to this deposition method, we were able to fabricate hundreds of operational devices in a reproducible way that were integrated in electronic chips. Following this first implementation, we decided to widen the application of the deposition technique to the field of Energy and specifically to the fabrication of supercapacitors. In this context, we demonstrated in 2012 the fabrication of nanostructured electrodes for supercapacitors, using mixtures of graphene/graphite and CNTs increasing the device capacitance and the power delivered of a factor 2.5 compared to CNT based electrochemical-double-layer-capacitors. Indeed, with high quality graphene we could reach a value of around 100 W Kg(-1). This value is extremely promising also considering that it has been obtained with an industrially suitable technique. This dynamic spray-gun deposition has been also exploited for the fabrication of resistance based random access memories, making use of thin layers of graphene oxide and of oxidized carbon nanofibers. In the first case, 5000 cycles of 'write' and 'read' phases were demonstrated. These results pave the way for the fabrication of very low cost memories that can be embedded in smart-cards, patches for health monitoring (e.g. diabetes), ID cards, RFID tags and more generally smart packaging. Finally we are also working on the utilization of this technique for the fabrication of layers for electro-magnetic interference shielding application. Thanks to a new machine with four nozzles, developed within the frame of the Graphene Flagship project, we are able to deposit four different nanomaterials at the same time or alternatively on a large surface (30 cm x 30 cm) creating specific nano-structuration and therefore ad hoc architectures allowing the smart absorption of specific frequencies (e.g. X-band). All these applications demonstrate the extreme versatility of this technique that constitutes a real breakthrough for exploiting the nanomaterials characteristics in real devices, using an industrial suitable fabrication method that can be implemented using roll-to-roll technique.

Quantum technologies have been identified as breakthrough technologies with a potential high impact on future navigation, sensing and communication systems since the end of the 90's. In this paper we will review how these technologies can contribute to electromagnetic spectrum dominance through the use of SHB (spectral hole burning) based spectral holography and of NV (nitrogen vacancy) centers in diamond. Quantum technologies, combined with integration techniques, will also improve the performances of navigation systems thanks to ultra-precise compacts atomic clocks, accelerometers and gyros.

We build a resonant fiber optic gyro based on Kagome hollow-core fiber. A semi-bulk cavity architecture based on an 18-m-long Kagome fiber permits achieving a cavity finesse of 23 with a resonance linewidth of 700 kHz. An optimized Pound-Drever-Hall servo-locking scheme is used to probe the cavity in reflection. Closed-loop operation of the gyroscope permits reaching an angular random walk as small as 0.004°/h and a bias stability of 0.45°/h over 0.5 s of integration time.

We present rotation measurements performed with a passive resonant optical fibre gyroscope. The fibre used to realize the resonant cavity was a Kagome Hollow Core Fiber. Measurements were performed in two types of configurations. In the first configuration, the counter propagating beams resonate on the same cavity mode. This leads to observation of lock-in that prevents measuring rotation rates below roughly 1°/s. In the second configuration, the counter propagating beams resonate on two different cavity modes. This leads to rotation rates measurements below 0.1°/s that are currently limited by some drifts. We will describe in the conference possible sources of drifts and the solutions we consider to circumvent them.