Scheduled System Maintenance:
On April 27th, single article purchases and IEEE account management will be unavailable from 2:00 PM - 4:00 PM ET (18:00 - 20:00 UTC).
We apologize for the inconvenience.
By Topic

Photonics Technology Letters, IEEE

Issue 7 • Date April1, 2012

Filter Results

Displaying Results 1 - 25 of 38
  • [Front cover]

    Publication Year: 2012 , Page(s): C1
    Save to Project icon | Request Permissions | PDF file iconPDF (184 KB)  
    Freely Available from IEEE
  • IEEE Photonics Technology Letters publication information

    Publication Year: 2012 , Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (34 KB)  
    Freely Available from IEEE
  • Table of contents

    Publication Year: 2012 , Page(s): 531 - 532
    Save to Project icon | Request Permissions | PDF file iconPDF (110 KB)  
    Freely Available from IEEE
  • Design and Analysis of Ultra-High-Speed Near-Ballistic Uni-Traveling-Carrier Photodiodes Under a 50- \Omega Load for High-Power Performance

    Publication Year: 2012 , Page(s): 533 - 535
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (423 KB) |  | HTML iconHTML  

    We demonstrate a near-ballistic uni-traveling-carrier photodiode (NBUTC-PD) with a scaled-down epi-layer structure designed for high-power performance in the sub-THz frequency regime. Compared with UTC-PDs, NBUTC-PDs offer a higher optimum bias voltage for the near-ballistic transport of electrons, which leads to improvement in the output power performance. Furthermore, a small load resistance ( <; 50&nbsp;Ω), which would sacrifice the output power for minimizing the output ac voltage swing on dc bias point, is not necessary. By scaling down the collector layer thickness and active area of the NBUTC-PDs, we achieve a large optical-to-electrical bandwidth (250 GHz) and a high saturation current (17 mA), which is close to the theoretical maximum, under a 50-Ω load and -2-V bias. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adiabatic Passage of Light in CMOS-Compatible Silicon Oxide Integrated Rib Waveguides

    Publication Year: 2012 , Page(s): 536 - 538
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (340 KB) |  | HTML iconHTML  

    A fully complementary metal-oxide-semiconductor-compatible adiabatic passage of light in the visible range is presented in this letter. We experimentally show that a system of three total internal reflection waveguides, which has been defined by using non-stoichiometric silicon oxide, allows a highly efficient transfer of light between the outermost waveguides by adiabatically following one eigenmode of the system. Furthermore, we demonstrate that such transfer of light is very robust against small variations of the system parameters. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High Repetition-Rate Narrow Bandwidth SESAM Mode-Locked Yb-Doped Fiber Lasers

    Publication Year: 2012 , Page(s): 539 - 541
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (631 KB) |  | HTML iconHTML  

    A stable narrow bandwidth semiconductor saturable absorber mirror mode-locked Yb-doped fiber laser was demonstrated in a short linear cavity with fundamental repetition rate up to 843 MHz. At the fundamental repetition rate of 490 MHz, the maximum output power was 17 mW at ~ 300-mW incident pump power. The center wavelength and the spectral bandwidth were 1064.1 and 0.13 nm, respectively, imposed by a narrow bandwidth fiber Bragg grating. The pulsewidth was measured to be 21 ps, and the time-bandwidth product of the laser pulse was 0.72. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Wavelet Denoising Method for Improving Detection Performance of Distributed Vibration Sensor

    Publication Year: 2012 , Page(s): 542 - 544
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (278 KB) |  | HTML iconHTML  

    This letter proposed and demonstrated a wavelet technique to reduce the time domain noise to get submeter spatial resolution in the distributed vibration sensor based on phase optical time domain reflectometry. A new wavelet shrinkage approach allows the distributed vibration measurement of 20-Hz and 8-kHz events to be detected over 1-km sensing length with a 5-ns optical pulse, which is equivalent to 50-cm spatial resolution using the single-mode sensing fiber. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance Analysis of Decode-and-Forward Relaying in Gamma-Gamma Fading Channels

    Publication Year: 2012 , Page(s): 545 - 547
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (198 KB) |  | HTML iconHTML  

    We analyze performance of the decode-and-forward (DF) protocol in the free space optical (FSO) links following the Gamma-Gamma distribution. The cumulative distribution function (cdf) and probability density function (pdf) of a random variable containing mixture of the Gamma-Gamma and Gaussian random variables is derived. By using the derived cdf and pdf, average bit error rate of the DF relaying is obtained. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Plasmonic Nanoslit Array Enhanced Metal–Semiconductor–Metal Optical Detectors

    Publication Year: 2012 , Page(s): 548 - 550
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (313 KB) |  | HTML iconHTML  

    Metallic nanoslit arrays integrated on germanium metal-semiconductor-metal photodetectors show many folds of absorption enhancement for transverse-magnetic polarization in the telecommunication C-band. Such high enhancement is attributed to resonant interference of surface plasmon modes at the metal-semiconductor interface. Horizontal surface plasmon modes were reported earlier to inhibit photodetector performance. We computationally show, however, that horizontal modes enhance the efficiency of surface devices despite reducing transmitted light in the far field. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Generation of 25-fs High Energy Pulses by SPM-Induced Spectral Broadening in a Photonic Crystal Fiber Laser System

    Publication Year: 2012 , Page(s): 551 - 553
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (537 KB) |  | HTML iconHTML  

    We demonstrate 25-fs laser pulse generation from a photonic crystal fiber (PCF) laser system, which consists of a high energy all normal dispersion mode-locked oscillator based on an ytterbium-doped large mode area PCF and a passive PCF-based grating-pair compressor. The oscillator directly delivers 314-nJ highly-chirped pulses with a duration of 1.32 ps at a repetition rate of 15.58 MHz, which can be dechirped to 75 fs, corresponding to a peak power of 3 MW. The output laser pulses from the oscillator are directly injected to a piece of passive PCF for spectral broadening and dechirped by a transmission grating pair compressor, which results in a short pulse duration of 25 fs with 1-W average power. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Temperature and Strain Sensing With Femtosecond Laser Written Bragg Gratings in Defect and Nondefect Suspended-Silica-Core Fibers

    Publication Year: 2012 , Page(s): 554 - 556
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (259 KB) |  | HTML iconHTML  

    The spectral behavior in the C-band of fiber Bragg gratings (FBGs) was analyzed as a function of temperature and strain. The FBGs were fabricated in pure silica four-leaf-clover-shaped suspended-core fibers by (DUV) femtosecond laser exposure (3.6 W at 800 nm, 130 fs, 1 kHz frequency tripled to 350 fs, 650 mW at 267 nm). A defect fiber (with a hollow hole in the core) and nondefect fiber were compared both yielding ≈1 pm/με sensitivity to strain but different sensitivity to temperature (from 3.0 pm/°C to 8.4 pm/°C for the defect fiber and 10 pm/°C for the nondefect fiber). The 16% to 70% relative difference between the thermal coefficients of the two fibers, together with their similar strain sensitivity enables the simultaneous measurement of strain and temperature. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Photothermal Group Delay Tuning in Nonpermanently Phase-Shifted Chirped FBGs

    Publication Year: 2012 , Page(s): 557 - 559
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (449 KB) |  | HTML iconHTML  

    A nonpermanent phase-shift can be locally created in a chirped fiber Bragg grating placed in contact to a thin heating wire. Changing the bias current value modifies the phase-shift (around π), which allows us to switch between a positive and negative delay variation at a specific wavelength. This mode of operation allows a wide-range tuning of the group delay in the structure. However, the tuning is rather slow and to overcome this limitation, we propose to exploit the photothermal effect. Using an optical pump emitting outside the grating spectral region, we can quickly tune the phase-shift value around π. The results demonstrate that the group delay can be all-optically tuned over a wide range and with relatively low optical powers. Experiments are confirmed by simulations. We believe that this structure may be advantageously used in microwave photonics. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Semiconductor Optical Amplifiers in Coherent Optical-OFDM Systems

    Publication Year: 2012 , Page(s): 560 - 562
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (662 KB) |  | HTML iconHTML  

    Experimental results of using a semiconductor optical amplifier (SOA) for amplification of a coherent optical-orthogonal frequency-division-multiplexing (CO-OFDM) transmission system are presented. The impact of the SOA nonlinearities on the amplification of a 10.94-Gb/s quadrature phase-shift keying CO-OFDM signal with respect to the input power, the signal wavelength, and the number of subcarriers is investigated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Inter-Carrier Interference Suppression in No-Guard-Interval Orthogonal Frequency-Division-Multiplexing System

    Publication Year: 2012 , Page(s): 563 - 565
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (349 KB) |  | HTML iconHTML  

    The inter-carrier interference (ICI) in the no-guard-interval orthogonal frequency-division-multiplexing (NGI-OFDM) system causes severe performance degradation when 2-samples/symbol (Sa/sym) digital signal processing (DSP) is used at the receiver. To enable narrow bandwidth devices and low sampling rate DSP, a novel ICI suppression (ICIS) method is proposed and experimentally demonstrated in this letter. The proposed method improves the performance of the 4-Gbaud 25-carrier NGI-OFDM system by up to 4 dB, and 2-Sa/sym DSP with ICIS achieves comparable performance as the conventional 8-Sa/sym DSP without ICIS, with moderately increased complexity. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Improvement of Photonic ADC Based on Phase-Shifted Optical Quantization by Using Additional Modulators

    Publication Year: 2012 , Page(s): 566 - 568
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB) |  | HTML iconHTML  

    An improvement of a photonic analog-to-digital converter based on phase-shifted optical quantization (PSOQ) is presented and verified. The resolution can be increased by employing an additional Mach-Zehnder modulator (MZM) to combine with the PSOQ scheme. The improved scheme with a quantization level of 32 (corresponding quantization bit number is 5 bits) is experimentally demonstrated by using two LiNbO3 modulators, and the experimental result with the effective number of bits 4.23 is obtained. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Millimeter-Sized Microfiber Coil Resonators With Enhanced Quality Factors by Increasing Coil Numbers

    Publication Year: 2012 , Page(s): 569 - 571
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (394 KB) |  | HTML iconHTML  

    Microfiber coil resonators (MCRs) with quality factors as high as ~470 000 and small size (<; 2 mm3) were fabricated and characterized. Both simulated and experimental results showed that the average full-width at half-maximum of the resonant dips decreased with the number of rings, providing a proof of the dependence of increasing quality factor upon the number of rings, even when the gaps among adjacent rings were not strictly uniform. Compared to the previous reports, a multi-ring MCR can thus offer a new choice of obtaining a microfiber resonator with high quality factor. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • 30-Gb/s Bidirectional Transparent Optical Transmission With an MMF Access and an Indoor Optical Wireless Link

    Publication Year: 2012 , Page(s): 572 - 574
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (533 KB) |  | HTML iconHTML  

    This letter describes a 30-Gb/s bidirectional transparent optical transmission, over a 4.4-km multimode fiber (MMF) in combination with an indoor optical wireless (OW) link, which could provide limited mobility. Due to MMF's advantages, such as lower installation costs and easy maintenance, it is used as the access link. To enhance the MMFs bandwidth and provide the feasibility to use standard single-mode devices in the OW terminal (OWT), center launching and center detection techniques are both utilized. The stability of the indoor OW channel and the modal noise in MMF are investigated. Discrete multitone modulation with power and bit loading algorithms are applied to improve system's frequency utilization efficiency and robustness. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Novel Method for Frequency Response Measurement of Optoelectronic Devices

    Publication Year: 2012 , Page(s): 575 - 577
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (294 KB) |  | HTML iconHTML  

    We develop a novel method to measure the frequency response of the optoelectronic devices. In this method, an electro-absorption modulator is utilized not only as a modulator but also as a photodetector with the identical frequency response. Based on this property, the frequency responses of the optoelectronic devices can be obtained and the results show good consistency with the measurement results by traditional methods. Instead of using broadband modulators or photodetectors, the frequency response of high bandwidth optoelectronic devices can be measured by using the low bandwidth optoelectronic devices. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Extruded Microstructured Fiber Lasers

    Publication Year: 2012 , Page(s): 578 - 580
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (271 KB) |  | HTML iconHTML  

    We present the first fiber laser fabricated from an extruded microstructured preform. This laser is also, to the best of our knowledge, the first microstructured tellurite glass fiber laser. The threshold and efficiency of the 980-nm pumped, 1.5-μm erbium-doped tellurite laser were measured to be 1.5 mW and 13%, respectively. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dependence of In-Band Incoherent Crosstalk-Induced Penalty on Seed Source in RSOA-Based WDM-PONs

    Publication Year: 2012 , Page(s): 581 - 583
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (279 KB) |  | HTML iconHTML  

    We have investigated the dependence of in-band incoherent crosstalk-induced power penalties on seed source in reflective semiconductor optical amplifier (RSOA)-based wavelength-division-multiplexed passive optical networks (WDM-PONs). The in-band crosstalk penalties in an RSOA-based WDM-PON were measured with two different seed sources; a broadband light source (BLS) and a distributed feedback laser diode (DFB-LD). The 1-dB power penalties with a BLS seeded and a DFB-LD seeded RSOA source were observed when the crosstalk-to-signal ratios were ~ -14 and -16&nbsp;dB, respectively. From the results, we found that the directly-modulated RSOA sources with a BLS or a DFB-LD seed source were more tolerant to the in-band crosstalk than an externally-modulated DFB-LD source. In addition, we confirmed that the in-band crosstalk-induced power penalty in the RSOA-based WDM-PONs could be calculated with a proper estimation of an equivalent optical source bandwidth. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Efficient FDTD Simulation of Active Photonic Devices With Multiple Temporal Resolutions

    Publication Year: 2012 , Page(s): 584 - 586
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (745 KB) |  | HTML iconHTML  

    A computational method to reduce computational time for finite-difference time-domain simulations of active photonic devices by using different temporal resolutions for the update of Maxwell's equations and active-medium (AM) equations are presented. A larger temporal resolution for the update of AM equations is used due to their slower evolution in comparison to the electromagnetic fields. Slow varying envelope approximation in the carrier rate equations are avoided. The method is easy to implement and is validated through numerical examples of semiconductor microdisk lasers. A speed enhancement of between two to threefold can be obtained without loss in accuracy. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Strain and Temperature Discrimination Using High Birefringence Fiber Sagnac Interferometer With Enhanced Sensitivities

    Publication Year: 2012 , Page(s): 587 - 589
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (238 KB) |  | HTML iconHTML  

    Discrimination between the strain and temperature variations based on the Sagnac interferometer is newly proposed and demonstrated with much improved properties. It is achieved by containing five sections of high birefringence fibers (HBFs) in the Sagnac interferometer-three of them spliced together act as the compact sensing head and the other two are isolated from the strain and temperature changes. By properly setting all the HBF lengths and relative orientations of their primary polarization axes, the strain and temperature sensitivity coefficients of the two wavelength dips generated due to the Sagnac interference may be greatly enhanced with the effectively reduced cross sensitivity. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Ultrafast Refractometry for Characterization of Nanocomposite Material Systems

    Publication Year: 2012 , Page(s): 590 - 592
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (725 KB) |  | HTML iconHTML  

    An ultrafast refractometry technique is introduced for direct characterization of refractive indices, absorption coefficients, and refractive index variances in nanocomposite (NC) assemblies. The system samples bulk NC optical characteristics by probing phase delay, absorption, and spatial coherence effects on an ultrashort laser probe pulse. The integrated system is demonstrated for representative samples of 20-nm SiC nanoparticles in a polymer host and is found to successfully sample the desired optical characteristics. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • SMS Fiber Sensor Utilizing a Few-Mode Fiber Exhibits Critical Wavelength Behavior

    Publication Year: 2012 , Page(s): 593 - 595
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (470 KB) |  | HTML iconHTML  

    We experimentally demonstrate the existence of a critical wavelength in the 1.4-1.6-μm optical communication window for the single-mode-multimode-single-mode (SMS) fiber sensor utilizing a few-mode fiber (FMF). Peaks near the critical wavelength exhibit higher sensitivity to temperature or strain. A theoretical analysis of this SMS structure shows that the critical wavelength behavior is mainly governed by the fiber refractive index (RI) profile with no significant effect from material dispersion. There is only one critical wavelength in the range where the LP02 mode of the FMF is supported. Small alterations of the fiber RI profile can tune the critical wavelength. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Thickness-Dependent Transient Photocurrent Response of Organic Photodiodes

    Publication Year: 2012 , Page(s): 596 - 598
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (904 KB) |  | HTML iconHTML  

    We report on the transient photocurrent response of organic photodiodes based on a bulk-heterojunction of polyhexylthiophene and -phenyl--butyric acid methyl ester. By changing the thickness of the active layer via different spin speeds we explore the influence of geometric capacitance and bias voltage on the transient photocurrent decay upon excitation with a nanosecond laser pulse. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

This letters journal addresses all aspects of the IEEE Photonics Society Constitutional Field of Interest with emphasis on photonic/lightwave components and applications, laser physics and systems and laser/electro-optics technology.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Dr. Seb J. Savory
University College London