Coherent terahertz photonics

Abstract

Abstract: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. References and links1. A. G. Davies and E. H. Linfield, eds., "Special Supplement: THz Technology," Electron. Lett. 46(26), (2010). 2. S. J. Savory, "Digital filters for coherent optical receivers," Opt. Express 16(2), 804-817 (2008). 3. H. Eisele, "480GHz oscillator with an InP Gunn device," Electron. Lett. 46(6), 422-423 (2010). 4. L. Moeller, J. Federici, and K. Su, "THz wireless communications: 2.5 Gb/s error-free transmission at 625 GHz using a narrow-bandwidth 1 mW THz source," XXXth URSI General Assembly and Scientific Symposium (2011). 5. C. C. Renaud, M. Robertson, D. Rogers, R. Firth, P. J. Cannard, R. Moore, and A. J. Seeds, "A high responsivity, broadband waveguide uni-travelling carrier photodiode," Proc. SPIE 61940, 61940C, 61940C-8 (2006

Accurate modelling and measurement of the impedance match between UTC photodiodes and THz antennas

“…The magnitudes of the measured S11 and the S11 obtained with CST and the equivalent circuit are all in excellent agreement up to 90 GHz and good agreement between 90 GHz and 110 GHz. The M. Natrella 1 Accurate modelling and measurement of the impedance match between UTC photodiodes and THz antennas P phases are all in excellent agreement up to 67 GHz, then measurement and circuit phases maintain good agreement up to 110 GHz, while CST phase begins to depart. Above 110 GHz the disagreement between the equivalent circuit and CST S11 becomes increasingly significant.…”

“…HOTONIC THz emitters, based on antennas integrated with UTC photodiodes [1][2][3], are promising candidates for the realisation of compact and efficient continuous-wave sources within the lower part of the THz spectrum (100 GHz -3 THz). Current research on antenna integrated UTC-PDs is focused on increasing the emitted power and bandwidth.…”

Building an end user focused THz based ultra high bandwidth wireless access network: The TERAPOD approach

“…THz antenna solutions are typically based on the employment of silicon lenses [28], [29].The high permittivity of the substrate leads to propagating modes and reflections within the substrate. It implies an unpredictable radiation pattern as a function of frequency.…”

Optical side-band generation in THz Fabry-Perot laser cavities

“…Using cavity up-conversion to detect THz signals in the NIR is appealing as it avoids the challenges of direct detection in the far infrared [2,5,6,14,15]. In THz QCLs we can exploit the large χ (2) nonlinear susceptibility of the GaAs active region for intra-cavity up-conversion.…”