The modified micromachined thermopile consists of linearly arranged thermopairs instead of the usual loops. This device
can act as a series of antennas and senses the millimeter wave radiation [1]. The antenna-like operation was
demonstrated by the strong dependence on the polarization. The working principle is similar to the bolometers in that
respect that the absorbed radiation heats up the semiconductor strips, but the temperature increment is sensed by the
Seebeck effect instead of the resistance increment. Therefore there is no read-out current and the voltage output starts
from zero. In the present work we are going to search absorption spectra of the device. It is shown that the resonance
depends mainly on the dimensions and shape of the chip; the linear thermopiles are rather E-field probes. The fabrication
of the device will be also outlined as well as the experimental results.
The combination of the optical and microwave techniques offers new approaches for the generation of microwave signals. That is made possible by the very high bandwidth of the optical devices and the very low attenuation of the optical fiber. The main general advantage of these approaches is the generation of very high frequencies with low noise. For the optical stabilization of microwave oscillators a clean reference signal is optically transmitted. However, instead of the millimeter wave signal, one of its subharmonics is optically transmitted and the millimeter wave signal is generated utilizing the subharmonic signal as a reference. This way the optical components become much simpler and cheaper. In this procedure a crucial point is the frequency division at millimeter waves. For this purpose a new method is introduced: the superharmonic injection locking of oscillators. Utilizing combined injection and phase locking techniques the frequency of the microwave oscillator is stabilized while its noise is significantly reduced.
In subcarrier multiplexed optical transmission systems the modulation linearity of the transmitter plays an important role because that nonlinearity gives rise to serious harmonic and intermodulation distortions. Therefore the modulation linearity of the laser has been significantly improved by applying an active matching technique. For that purpose, the microwave impedance of the laser has been measured as a function of the bias current and frequency. Based on the measured data, a nonlinear equivalent circuit has been derived that was used in the matching process. As a result, a significant improvement in the laser modulation linearity has been attained.
Conference Committee Involvement (10)
Emerging Technologies IV
11 September 2019 | Strasbourg, France
Emerging Technologies
12 September 2018 | Berlin, Germany
Emerging Imaging and Sensing Technologies
13 September 2017 | Warsaw, Poland
Emerging Imaging and Sensing Technologies
28 September 2016 | Edinburgh, United Kingdom
Emerging Technologies
23 September 2014 | Amsterdam, Netherlands
Emerging Technologies
25 September 2013 | Dresden, Germany
Emerging Technologies
24 September 2012 | Edinburgh, United Kingdom
Photonic Components and Architectures in Defence Systems
3 September 2009 | Berlin, Germany
Photonic Components and Architectures for Microwave Systems and Displays II
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