Article

Traveling-wave Uni-Traveling Carrier Photodiodes for continuous wave THz generation

UCL Electronic and Electrical Engineering, Torrington Place, London WC1E 7JE, UK.
Optics Express (Impact Factor: 3.49). 05/2010; 18(11):11105-10. DOI: 10.1364/OE.18.011105
Source: PubMed

ABSTRACT

The design, experimental evaluation and performance of a Traveling-Wave Uni-Traveling Carrier photodiode for Terahertz generation are described and its advantages in terms of frequency response are demonstrated. The device delivered 148 microW at 457 GHz, 24 microW at 914 GHz when integrated with resonant antennas and 105 microW at 255 GHz, 30 microW at 408 GHz, 16 microW at 510 GHz and 10 microW at 612 GHz. Record levels of Terahertz figure of merit (PTHz/Popt2 in W(-1)) were achieved ranging from 1 W(-1) at 110 GHz to 0.0024 W(-1) at 914 GHz.

Download full-text

Full-text

Available from: Cyril Renaud, Apr 28, 2015
  • Source
    • "Up to now various optical and electrical methods have been used for THz sources [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]; however at present, achieving compact, efficient, and economic sources remains a challenge to scientists and engineers [11] [12] [13] [14]. One of the main optical methods for CW THz wave generation is heterodyne method that uses THz beat frequency of two frequency-locked laser beams with two different frequencies [10] [11]. In heterodyne method, the THz beat frequency can be tuned by changing the optical frequency of lasers. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We demonstrate an all-optical modulator based on self-modulation in a one-dimensional slab photonic crystal (PhC) by using optical Kerr nonlinearity of graphene and Fano resonance effect. It has been shown that the effect of Fano resonance in a one-dimensional slab PhC for intensity enhancement can provide low threshold (~1 MW/cm 2 ), high frequency (>1 THz), and wide dynamic range (>3 THz) tunability for the all-optical self-modulator. Such a self-modulator can find applications in optical pulse generations, optical clocks, frequency shifting, and so forth.
    Full-text · Article · Nov 2015 · Journal of Nanotechnology
  • Source
    • "The bandwidth of PDs in this paper is lower than other works on Si [7], [8], [10]. It can be improved by shrinking the size of the active regions and using the design of uni-traveling-carrier PDs [32], [33]. The responsivity of the WGPD device can be much improved with better coupling. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We report selective-area growth of high-crystalline-quality InGaAs-based photodetectors with optimized InP/GaAs buffers on patterned (100)-oriented silicon-on-insulator (SOI) substrates by metal-organic chemical vapor deposition. The composite GaAs and InP buffer was grown using a two-temperature method. The island morphology of the low-temperature GaAs nucleation layer inside the growth well of the SOI substrate was optimized. A medium temperature GaAs layer was inserted prior to the typical high-temperature GaAs to further decrease the dislocation densities and antiphase boundaries. Both normal-incidence photodetectors and butt-coupled waveguide photodetectors were fabricated on the same substrate and showed a low dark current and high-speed performance. This result demonstrates a good potential of integrating photonic and electronic devices on the same Si substrate by direct epitaxial growth.
    Full-text · Article · Nov 2014 · IEEE Journal of Selected Topics in Quantum Electronics
  • Source
    • "integrated two UTC devices on the same chip and their combined power output showed record high power of 1 mW at 300 GHz [17]. To date, the best results in waveguide based devices have been obtained in work when the standard UTC structure was used in combination with an optimized pseudo TW design [18], [19]. The devices were not full travelling wave structures as this can only be achieved in periodic structures. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Optical fibre transmission has enabled greatly increased transmission rates, with 10 Gb/s common in local area networks. End users find wireless access highly convenient for mobile communication. However, limited spectrum availability at microwave frequencies results in per-user transmission rates limited to much lower values, 500 Mb/s for 5 GHz band IEEE 802.11ac, for example. Extending the high data-rate capacity of optical fibre transmission to wireless devices, requires greatly increased carrier frequencies. This paper will describe how photonic techniques can enable ultra-high capacity wireless data distribution and transmission using signals at millimetre-wave and TeraHertz (THz) frequencies.
    Full-text · Article · Jan 2014 · Journal of Lightwave Technology
Show more