1. Soliton Pulses in Photonic Crystal Fabry-Perot Microresonators(arXiv)
Author : Thibault Wildi, Mahmoud A. Gaafar, Thibault Voumard, Markus Ludwig, Tobias Herr
Abstract : Femtosecond dissipative Kerr solitons (DKS) in high-Q microresonators enable novel applications in spectroscopy, sensing, communication and signal processing. Usually, DKS pulses are generated in traveling-wave ring-resonators driven by continuous-wave lasers. Although immensely successful, conventional ring-resonators offer only few design parameters, limiting the potential of DKS. Here, we demonstrate for the first time CW-driven DKS in a high-Q standing-wave Fabry-Perot microresonator. In contrast to conventional ring-type resonators, two photonic crystal reflectors in a waveguide define the resonator, opening a large design space with prospects for future extension of DKS to visible wavelengths and other spectral domains that are so far inaccessible. The chip-integrated resonator is compatible with wafer-level fabrication and its intrinsic Q-factor of 4 million is on-par with ring-resonators. Beyond DKS, this creates opportunities for filter-driven pulse formation, engineered spectra and, more generally, phase-matching for broadband frequency conversion in integrated nonlinear photonics
2.A fiber Fabry-Perot cavity based spectroscopic gas sensor (arXiv)
Author : Carlos Saavedra, Deepak Pandey, Wolfgang Alt, Dieter Meschede, Hannes Pfeifer
Abstract : Optical spectroscopic sensors are powerful tools for analysing gas mixtures in industrial and scientific applications. Whilst highly sensitive spectrometers tend to have a large footprint, miniaturized optical devices usually lack sensitivity or wideband spectroscopic coverage. By employing a widely tunable, passively stable fiber Fabry-Perot cavity (FFPC), we demonstrate an absorption spectroscopic device that continuously samples over several tens of terahertz. Both broadband scans using cavity mode width spectroscopy to identify the spectral fingerprints of analytes and a fast, low-noise scan method for single absorption features to determine concentrations are exemplary demonstrated for the oxygen A-band. The novel scan method uses an injected modulation signal in a Pound-Drever-Hall feedback loop together with a lock-in measurement to reject noise at other frequencies. The FFPC-based approach provides a directly fiber coupled, extremely miniaturized, light-weight and robust platform for analyzing small analyte volumes that can straightforwardly be extended to sensing at different wavelength ranges, liquid analytes and other spectroscopic techniques with only little adjustments of the device platform.
3. Design and Fabrication of a Differential MOEMS Accelerometer Based on Fabry Perot micro-cavities(arXiv)
Author : Mojtaba Rahimi, Mohammad Malekmohammad, Majid Taghavi, Mohammad Noori and, Gholam Mohammad Parsanasab
Abstract : In this paper, a differential MOEMS accelerometer based on the Fabry-Perot (FP) micro-cavities is presented. The optical system of the device consists of two FP cavities and the mechanical system is composed of a proof mass that is suspended by four springs. The applied acceleration tends to move the PM from its resting position. This mechanical displacement can be measured by the FP interferometer formed between the proof mass cross-section and the optical fiber end face. The proposed sensor is fabricated on a silicon on insulator (SOI) wafer using the bulk micromachining method. The results of the sensor characterization show that the accelerometer has a linear response in the range of 1g. Also, the optical sensitivity and resolution of the sensor in the static characterization are 6.52 nm/g and 153ug. The sensor sensitivity in the power measurement is 49.6 mV/g and its resonant is at 1372 Hz. Using the differential measurement method increases the sensitivity of the accelerometer. Based on experimental data, the sensor sensitivity is two times as high as that of a similar MOEMS accelerometer with one FP cavity
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