Tuesday, 27 September – 1 st Quarter Regular Sessions (08:30 – 10:15)
Clyde Auditorium
Tu1.1 08:30 – 09:30
Optimizing Terrestrial Systems for 40Gbit/s Channel Rate
S Bigo, Alcatel Research and Innovation, France
Although the expected time for mass deployment of 40 Gbit/s channel rate in commercial systems is still debated, few people doubt that it will come. Various strategies for its implementation can be proposed, whether starting from scratch or making the most of the existing fibre and amplifier infrastructures.
We review some of the possible strategies. Based on laboratory experiments, we discuss how the performance (capacity, distance, bit-error ratio) is affected versus the fraction of the already-installed system base being re-used. This performance is dependent on some high bit-rate-specific impairments, such as intra-channel nonlinear effects or polarization-mode dispersion (PMD), which we are addressed in the presentation. In order to minimize these impairments, the optical amplifier scheme and the distribution of dispersion compensating modules along the system should preferably be updated, whenever possible. However, departing from conventional modulation formats is one of the solutions which offer the greatest promises for the introduction of 40Gbit/s.
Sebastien Bigo graduated from the Ecole Supérieure d'Optique of Orsay, France in 1992. He joined Alcatel Research and Innovation, where he received a phD granted by the University of Besançon for a work on all-optical signal processing for soliton undersea systems. He became in charge of multi-terabit/s WDM terrestrial systems, with a specific focus on optical nonlinearities and on the impact of the fibre parameters on transmission performance. He is now heading the WDM transmission group, focusing on point-to-point terrestrial and submarine systems, as well as on transparent optical networks.
His team has reported 15 transmission records out of large-scale WDM system demonstrators from 320Gb/s to 10Tbit/s. He holds 27 patents and has authored and co-authored 120 conference and journal papers, including 14 papers at the post-deadline sessions of OFC, ECOC and OAA conferences. With three colleagues, he authored the reference book « Erbium-doped fiber amplifiers: device and system developments ». He is a member of IEEE and of the Technical Committee of LEOS Annual Meeting. Besides, he teaches optical communications at Paris XI University.
Lomond Audithorium
Tu1.2 – System Impairments
Chair: Jean-Pierre Hamaide, Alcatel Research and Innovation, France
Tu1.2.1 08:30 – 08:45
Nonlinear Phase Noise and Distortion in 42.7-Gbit/s RZ-DPSK Systems
M Ohm , University of Stuttgart , Germany, R-J Essiambre , P J Winzer, Bell Labs, Lucent Technologies , United States
We numerically study and isolate the impact of nonlinear phase noise and intrachannel nonlinearities in 42.7-Gbit RZ-DPSK transmission over 32x100-km non-zero dispersion-shifted fibre (NZDSF) for different scenarios of optical noise loading.
Tu1.2.2 08:45 – 09:00
Influence of Cross-Phase Modulation Induced Nonlinear Phase Noise on DQPSK Signals from Neighbouring OOK Channels
H Griesser , J-P Elbers, Marconi Communications Gmbh, Germany
We develop a model for cross-phase modulation induced nonlinear phase noise on DQPSK signals from neighbouring OOK channels and investigate the impact of 10 Gb/s OOK channels on 40 Gb/s DQPSK performance.
Tu1.2.3 09:00 – 09:15
Performance Improvement of NRZ-DPSK Transmission by Means of Optical Limiters Using Four-Wave Mixing in a Fibre
M Matsumoto, Osaka University, Japan
Reduction of nonlinear phase noise in DPSK transmission by the use of optical limiters based on FWM in a fibre is discussed. Numerical simulation shows performance improvement of high-speed NRZ-DPSK transmission by the optical limiters.
Tu1.2.4 09:15 – 09:30
Combined Constrained and Error Control Coding in Suppression of Intrachannel Fibre Nonlinearities
I B Djordjevic, B Vasic, University of Arizona, United States
A combined constrained-iterative FEC scheme for high-speed long-haul transmission is proposed. It can operate in the presence of strong intrachannel nonlinearities when even advanced FEC schemes would be overwhelmed with errors, and provides the coding gain of 12 dB at BER of 10^(-9).
Tu1.2.5 09:30 – 09:45
Optimum Fibre Dispersion for 40 Gbit/s DPSK Transmission
J K Fischer , S Randel, A Denzin, K Petermann, Technische Universität Berlin , Germany
The impact of fibre chromatic dispersion on 40 Gbit/s on-off keying and differential phase-shift keying transmission is compared by means of numerical simulation. The optimum fibre type is identified for various duty-cycles. While NZDSF is the optimum choice for OOK-formats, SSMF is preferable for RZ-DPSK.
Tu1.2.6 09:45 – 10:00
Mitigation of Fibre Nonlinearity and Chromatic Dispersion in 40 Gbit/s NRZ WDM Transmission using a Multichannel Optical Equalizer
V Mikhailov , S Appathurai, R I Killey, P Bayvel, University College London , United Kingdom , C R Doerr , Bell Laboratories, Lucent Technologies , United States
We investigated the mitigation of distortion due to SPM and dispersion in 40 Gbit/s NRZ WDM transmission using a multichannel optical equalizer. We achieved 21 channel transmission at BER < 10-9 without FEC over 750 km of TWRS fibre, with 107 km amplifier span lengths.
Tu1.2.7 10:00 – 10.15
Relative Impact of the Different Intrachannel Nonlinear Effects over 43 Gb/s Transmissions with Varying Fibre Dispersion
M Lefrançois , E Barnasson , G Charlet , J-C Antona , S Bigo , Alcatel Research and Innovation , France
A numerical method is proposed to accurately discriminate the influence of each intrachannel nonlinear effect. In contrast to other studies, we obtain that i-FWM is the most penalizing effect in all our investigated 43Gb/s cases.
Argyll Suite
Tu1.3 – High-Speed PONs
Chair: Gert Schiellerup, Tellabs Denmark, Denmark
Tu1.3.1 08:30 – 09:00
Invited - 10 Gbit/s Bidirectional Transmission in 1024-Way Split, 110 km Reach, PON System using Commercial Transceiver Modules, Super FEC and EDC
D Nesset , R P Davey, BT , United Kingdom , D Shea , University College London , United Kingdom, P Kirkpatrick, S Q Shang, Intel Corporation , United States, M Lobel, B Christensen, Intel Corporation , Denmark
We report error-free transmission at 10 Gbit/s over a 110 km, amplified PON using XFP and 300-pin MSA transceivers, super FEC and EDC. Bidirectional operation is implemented over a single fibre in the access network.
Tu1.3.2 09:00 – 09:15
Experimental Study on 10Gbit/s E-PON System Using XENPAK-Based Burst-Mode Transceivers
K Tanaka , N Edagawa, KDDI R&D Laboratories Inc. , Japan
We have experimentally evaluated a 10Gbit/s E-PON system using XENPAK-based burst-mode transceivers for the first time, and have confirmed that around 4Gbps upstream throughput can be expected with two ONUs, even using XENPAK-based transceivers.
Tu1.3.3 09:15 – 09:30
First Demonstration of Full Burst Optical Amplified GE-PON Uplink with Extended System Budget of up to 128 ONU Splits and 58 km Reach
N Suzuki , J Nakagawa, Mitsubishi Electric Corporation , Japan
We present a novel burst optical amplified GE-PON uplink employing a linear-gain 1.3µm shared SOA. An extended system budget supporting 128 ONU and 58km reach with burst penalty of less than 0.2dB was successfully achieved.
Tu1.3.4 09:30 – 09:45
Development of Optical Interfaces for GE-PON PX-20 Supporting a 64x Split Ratio and 20km Transmission Range
J Nakagawa , N Suzuki, C Han, T Uo, Mitsubishi Electric Corporation , Japan
We have developed ONU and OLT optical interfaces for GE-PON PX-20, which can support a 64x split ratio and 20km transmission range. 13.0Mbps upstream and 13.4Mbps downstream guaranteed bandwidth allocation are successfully demonstrated with 3.4dB power budget margin.
Tu1.3.5 09:45 – 10:00
Influence of Stimulated Raman Scattering in Video Overlay EPON Systems on Downstream Data Signal
A Agata , A Murakami, K Imai, Y Horiuchi, N Edagawa , KDDI R&D Laboratories Inc. , Japan
Influence of stimulated Raman scattering in video overlay EPON system on data signal has experimentally, numerically and analytically studied for the first time. The impact was found to have strong video signal optical power dependency.
Tu1.3.6 10:00 – 10:15
Colourless ONU Modules in TDM-PON and WDM-PON Architectures for Optical Carrier Remote Modulation
N Genay , P Chanclou, M Moignard, F Payoux, France Telecom R&D , France , R Brenot, Alcatel-Thales III-V Lab, France
A comparison is made between different solutions for colourless ONUs in several architectures using remote modulation of an optical carrier for 20 km transmission. ONU modules are compared in TDM-PON and WDM-PON architectures
Forth Room
Tu1.4 – Microstructured Fibres I
Chair: David Richardson, Optoelectronics Research Center, United Kingdom
Tu1.4.1 08:30 – 09:00
Invited - Highly Birefringent Lamellar Core Fibre
A Wang , A K George, J F Liu, J C Knight, P St J Russell, University of Bath , United Kingdom
We report a polarisation-maintaining fibre in which the birefringence is due to artificially introduced anisotropy in the core material. We measured a beat length as short as 85 microns at 543 nm wavelength.
Tu1.4.2 09:00 – 09:15
A New Photonic Bandgap Fibre with Extended Triangular Lattice and Capillary Core
K Takenaga , N Guan, R Goto, S Matsuo, K Himeno , Fujikura Ltd. , Japan
We present a PBGF composed of an extended-triangular-lattice cladding and a capillary core, which potentially have wide bandgaps without interface modes. A manufactured fibre exhibits a transmission range from 1520 nm to over 2100 nm.
Tu1.4.3 09:15 – 09:30
Singlemode Low-Index Liquid Core Holey Fibre
S Février , P Viale, M Lelek, F Louradour, J-L Auguste, P Roy, J-M Blondy , IRCOM , France
The hollow core of a photonic crystal fibre has been entirely filled with ethanol (n=1.36). A single LP11 mode is guided at 830nm by total internal reflection thanks to the large air-fraction in the cladding.
Tu1.4.4 09:30 – 09:45
Characterisation of Microstructured Fibre Hole Diameter and Pitch With Fourier Domain Optical Coherence Tomography
J C Jasapara , OFS Laboratories , United States
Fourier domain optical coherence tomography is used to non-invasively measure the spacing and diameters of holes in microstructured fibres providing the first route to monitoring hole parameters in real time during fibre draw.
Tu1.4.5 09:45 – 10:00
Using Modulation Instability to Determine the Propagation Constant in a Photonic Crystal Fibre
G K L Wong , A Y H Chen, S Ha, R J Kruhlak, S G Murdoch, R Leonhardt, J D Harvey, University of Auckland , New Zealand , J D Harvey , N Y Joly, J C Knight, W J Wadsworth, P St J Russell , University of Bath , United Kingdom
A novel method is proposed to measure the propagation constant of a photonic crystal fibre. The method makes use of modulation instability generated by pumping around the zero-dispersion wavelength of the fibre.
Tu1.4.6 10:00 – 10:15
A High Performance GeO2/SiO2 NZ-DSF and the Prospects for Future Improvement using Holey Fibre Technology
K Mukasa , F Poletti, D Richardson, University of Southampton , United Kingdom , K Imamura , N Kumano, T Yagi, Furukawa Electric Co., Ltd. , Japan
A new type of GeO2/SiO2 NZ-DSF with an attenuation loss of 0.174dB/km, a dispersion slope of ~0.06ps/nm 2 /km and an Aeff of ~70µm 2 at 1.55µm have successfully been developed. Holey Fibre designs offering reduced dispersion slopes for similar Aeffs are also reported.
Alsh Room
Tu1.5 – Mode Locking and Pulse Generation
Chair: Liam Barry, Dublin City University, Ireland
Tu1.5.1 08:30 – 09:00 Invited - Thermodynamic-Like Nature of Mode-Locking and Pulse Formation
A Gordon, R Weill, B Vodonos, A Rosen, M Katz, O Gat, B Fischer, Technion – Israel Institute of Technology, Israel
Pulse formation in mode-locked lasers is shown to follow a rich thermodynamic-like behavior with phase transitions, mode to pulse condensation and critical phenomena, explaining and predicting basic and practical features, like the threshold pulsation dependence on power and noise.
Tu1.5.2 09:00 – 09:15
High-Power, High Repetition Rate, Short-Pulse Mode-Locking using Flared Waveguide Quantum-Dot Lasers at 1.3µm
M G Thompson , F K Lau, R L Sellin, C Marrinelli, R V Penty, I H White, University of Cambridge , United Kingdom , A R Kovsh , S S Mikhrin ,
D A Livshits , N N Ledenstov , I L Krestnikov , NL Nanosemiconductor GmbH, Germany
Ultra-short pulse, high power mode-locking is demonstrated in InGaAs quantum dot lasers using a flared waveguide design. 24GHz mode-locking with 790fs wide pulses and 500mW peak powers suitable for telecommunications applications are presented.
Tu1.5.3 09:15 – 09:30
40 GHz Semiconductor Mode-Locked Laser Pulse Source for 160 Gbit/s RZ-DPSK Data Transmission
C Schubert , S Ferber, M Kroh, C Schmidt-Langhorst, R Ludwig, B Hüttl, R Kaiser, H G Weber, Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institut , Germany
We report on a monolithically integrated mode-locked semiconductor laser with 40 GHz repetition rate, suitable for RZ-DPSK transmission. The performance of the source is demonstrated in a 160 Gbit/s RZ-DPSK transmission experiment over 480 km.
Tu1.5.4 09:30 – 09:45
Sub-Picosecond Pulse Generation at 1.56 µm Using a Mode-Locked Quantum Dot Laser
A Martinez , C Gosset, K Merghem, G Aubin, A Ramdane, CNRS Laboratory Of Photonics And Nanostructures , France , F Lelarge , J Landreau , Alcatel Thales III-V Lab , France
We demonstrate ~500 fs pulse generation at a 53 GHz repetition rate using a two-section mode-locked quantum dot laser emitting at 1.56 µm. A very low 47 kHz linewidth of the carrier frequency at 43 GHz is reported.
Tu1.5.5 09:45 – 10:00
High Extinction Ratio Picosecond Pulses at 40GHz Rate Over 40nm with an AlGaInAs EAM Characterised by a Spectrogram Acquisition Method
J-G Provost , C Kazmierski, F Blache, J Decobert , Alcatel Thales III-V Lab , France
New AlGaInAs EAM provides optical picosecond pulses with a high Extinction Ratio over a 40nm large spectral range at 40GHz rate suitable for WDM NRZ-RZ conversion. Pulses are characterised by a high sensitivity spectrogram method.
Tu1.5.6 10:00 – 10:15
Optical Comb Generator Using Pulse Compression in Ultra-Long Semiconductor Amplifiers
C Bornholdt , J Slovak, B Sartorius, M Schlak, Ch Schmidt, Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institut , Germany
A novel pulse compression technique using an ultra-long semiconductor optical amplifier is presented. High quality 2ps pulses were generated out of 40GHz sinusoidal signal of a PhaseCOMB-laser enabling several applications for optical signal processing.
Boisdale Room
Tu1.6 – Planar Photonic Crystals
Chair: Hanne Ludvigsen , Helsinki University of Technology, Finland
Tu1.6.1 08:30 - 08:45
Low Loss and Low Crosstalk Waveguide Crossings with Small Angles Designed by Wavefront Matching Method
T Saida , Y Sakamaki, M Tamura, T Hashimoto , H Takahashi , NTT Corporation , Japan
We report experimental results for small-angle waveguide crossings designed with our recently proposed wavefront matching method. We successfully obtained lower loss and crosstalk values than conventional straight waveguide crossings.
Tu1.6.2 08:45 – 09:00
A Compact and Highly Accurate DOP Monitor Using Photonic Crystal Polariser Array
N Hashimoto , Y Homma, Innovation plaza Miyagi, JST , Japan , T Sato, T Aoyama, Photonic-Lattice Inc , Japan, T Chiba, H Uetsuka, Hitachi Cable, Ltd , Japan , S Kawakami, Sendai Foundation for Applied Information Sciences , Japan
We have developed a new type of DOP monitor having high measurement accuracy of less than 1 %. The DOP monitor was realized by using a monolithically integrated polarizer array manufactured by the auto-cloning technology.
Tu1.6.3 09:00 – 09:15
Broad Band Superprism Effect of Triangular One-dimensional Ta 2 O 5 Photonic Crystal Embedded in Slab Waveguide
K Oya , New Glass Forum , Japan , T Nakazawa, S Kittaka, K Tsunetomo, Nippon Sheet Glass Co., Ltd. , Japan, K Kintaka, J Nishii, AIST Kansai , Japan , K Hirao , Kyoto University , Japan
We first fabricated the triangular one-dimesional Ta2O5 photonic crystal embedded in slab waveguide. Super-prism effect, which was 1.7 times as large as that of our previous SiO2 photonic crystal, was attained in 100-nm wavelength region.
Tu1.6.4 09:15 – 09:30
Experimental Results and 3D Analysis of a High Efficiency Coupling Technique for Planar Photonic Crystals
P Sanchis , J Marti, Nanophotonics Technology Center, Universidad Politécnica de Valencia , Spain , W Bogaerts, P Dumon, R Baets , Ghent University-IMEC, Belgium
Experimental results of a high efficiency coupling technique for planar photonic crystals are reported. A 3D analysis is carried out to analyze the influence of out-of-plane losses and the discrepancies with 2D simulation results.
Tu1.6.5 09:30 – 09:45
Air Hole Photonic Crystal Beamsplitters Integrated in Ridge Waveguide Configuration
P Pottier , S Mastroiacovo, R M De La Rue, University of Glasgow , United Kingdom
Power and polarisation beamsplitters have been designed and fabricated, using air hole photonic crystal elements in SOI ridge waveguide T-junctions. 3D FDTD simulations show 99 % efficiency for power splitting, with around 90 % measured experimentally.
Tu1.6.6 09:45 – 10:00
Experimental Demonstration of a Vertically Coupled Photonic Crystal Filter
M Dainese , Z Zhang, L Wosinski, M Qiu, L Thylen, Royal Institute of Technology , Sweden , M Swillo , PhoXtal Communications AB, Sweden
Design, fabrication, and characterization of an optical filter based on vertical coupling between a silicon wire waveguide and a cavity in a suspended silicon photonic crystal membrane is presented for the 1550nm wavelength spectral region.
Tu1.6.7 10:00 - 10:15
Photo-Patternable Polymer Waveguides for Microring Resonators
R Dekker , M B J Diemeer , E J Klein , L T H Hilderink , K Wörhoff , A Driessen , University of Twente, Integrated Optical Micro Systems , The Netherlands
Low-cost fabrication of passive and rare-earth ion doped microring resonators using high refractive index photo patternable polymers is presented. Filter characteristics are shown for varying gaps and coupling lengths in case of an air cladding.
Tuesday, 27 September – 3 rd Quarter Regular Sessions (14:00 – 15:45)
Lomond Auditorium
Tu3.2 – Electronic Mitigation of Impairments I
Chair: Giancarlo Prati, CNIT, Italy
Tu3.2.1 14:00 - 14:30
Invited - Electronic Dispersion Compensation Techniques for Optical Communication Systems
M O'Sullivan, K Roberts, C Bontu, Nortel Networks, United States
Electronic domain methods of optical dispersion compensation are presented. It is shown that electric field modulation with electronic pre-compensation at the transmitter can substantially eliminate the need for optical compensators.
Tu3.2.2 14:30 – 15:00
Invited - Fibre Nonlinearities in Electronically Pre-Distorted Transmission
R-J Essiambre , P J Winzer, Bell Labs, Lucent Technologies , United States
A study on the impact of fibre nonlinearities in electronically pre-distorted wavelength-division-multiplexed transmission systems is presented. Large performance variations are observed due to the strong dependence of cross-phase modulation on pre-distorted neighbouring channels waveforms variations.
Tu3.2.3 15:00 – 15:15
Skewed Coding for Suppression of Pattern-Dependent Errors
A Shafarenko , University of Hertfordshire , United Kingdom , K S Turitsyn, Landau Institute for Theoretical Physics , Russia , S K Turitsyn , Aston University , United Kingdom
We present information theory analysis of the trade-off between BER improvement and the data rate loss using skewed channel coding to suppress pattern-dependent errors.
Tu3.2.4 15:15 – 15:30
8.4 dB Net Coding Gain Achieved with a Serially Concatenated Coding Scheme for Differential Quadrature Phase Shift Keyed Optical Systems
P Faraj , S Schöllmann , J Leibrich , W Rosenkranz , University of Kiel , Germany
We improve the system performance using Differential Quadrature Phase Shift Keying modulation format combined with a 100% overhead Convolutional Code concatenated with the standard Reed-Solomon code RS(255,239).
Tu3.2.5 15:30 – 15:45
Performance Evaluation of FEC Codes in Highly Spectrally Efficient 42.6 Gbit/s Coherent WDM Optical Transmission System
T Healy , F C Garcia Gunning , A D Ellis , University College Cork , Ireland
We report the first evaluation of FEC codes operating at 42.6 Gbit/s in a Coherent WDM transmission system with a spectral efficiency of 1 bit/s/Hz.
Tu3.3 – Wavelength Conversion and Regeneration
Chair: Peter Andrekson, Chalmers University of Technology, Sweden
Tu3.3.1 14:00 – 14:15
All-Optical Regeneration of 40-Gb/s Low-Q Signal Using XPM-Induced Wavelength Shift in Highly-Nonlinear Fibre
J Suzuki , T Tanemura, K Kikuchi, The University of Tokyo , Japan
We demonstrate all-optical regeneration of a 40-Gb/s low-Q signal, whose BER is as low as 10-4, using cross-phase modulation in a highly nonlinear fibre. Such a regenerator is compatible with a FEC-employing system.
Tu3.3.2 14:15 – 14:30
Investigation of Fibre Launch Power Margin in 40 Gb/s Transmission with All-Optical Regeneration
G Gavioli , B Thomsen, V Mikhailov, P Bayvel, University College London , United Kingdom
An experimental investigation of 40 Gb/s transmission with all-optical regeneration using an SOA-assisted fibre interferometer is reported. A dynamically-reconfigurable optical fibre loop is used to investigate the regenerator dynamic range
Tu3.3.3 14:30 – 14:45
Performance Limits of Electronic Feed-Forward and Decision Feedback Equalizers for Single Mode Fibre Links
P M Watts , V Mikhailov, S Savory, P Bayvel, R I Killey, University College London , United Kingdom , M Glick, Intel Research Cambridge, United Kingdom , M Lobel , B Christensen, Intel Copenhagen ApS, Denmark , P Kirkpatrick , S Shang , Intel Corporation , United States
The performance limits of 10Gb/s optically amplified single mode fibre links using electronic FFE and DFE are experimentally and numerically investigated. The optimum configuration and maximum single span transmission distance are determined.
Tu3.3.4 14:45 – 15:00
Wavelength Conversion of a 6 x 40 Gb/s DPSK WDM Signal using FWM in a Highly Non-linear Photonic Crystal Fibre
Y Geng , P A Andersen, T Tokle, C Peucheret, P Jeppesen, Technical University of Denmark, Denmark
We demonstrate FWM wavelength conversion of a 6x40Gb/s DPSK WDM signal in HNL-PCF. We show a conversion efficiency better than –20.3dB for 25dBm pump power and a power penalty less than 4.1dB for all channels.
Tu3.3.5 15:00 – 15:15
Wavelength-Conversion and Demultiplexing of an 80 Gbit/s Signal Using XPM-induced Wavelength Shift in Bismuth Oxide-Based Nonlinear Fibre
J H Lee , T Nagashima, T Hasegawa, S Ohara, N Sugimoto, Asahi Glass Co., Ltd , Japan, K Kikuchi , University of Tokyo , Japan
We experimentally demonstrate the use of one- and two-meter Bi2O3-based highly nonlinear fibres with gamma=~1100/W/km for wavelength conversion and demultiplexing of 80-Gbit/s OTDM signals. Error-free operation is achieved with wavelength conversion over a 10-nm range.
Tu3.3.6 15:15 – 15:45
Invited - Trends in the Field of All-Optical Wavelength Conversion and Regeneration for Communication up to 160 Gb/s
J Leuthold, W Freude, G Boettger, J Wang, P Vorreau, A Marculescu, University of Karlsruhe, Germany
Forth Room
Tu3.4 – Network Control and GMPLS
Chair: Ken-ichi Sato, University of Nagoya, Japan
Tu3.4.1 14:00 - 14:30
Invited - Nationwide Field Trial of GMPLS Optical Networking
T Otani, KDDI R&D Laboratories, Japan
The demonstrated results of nation-wide field trials of GMPLS optical networking are reviewed. The future view of GMPLS development is also discussed as results of the interoperability demonstration and operational experience.
Tu3.4.2 14:30 – 14:45
A GMPLS-Controlled Multi-Vendor Optical Network Demonstrating a Variety of Switching, Control, and Protection Mechanisms
M Mir , H Sheikh, G Galimberti, R Ati, S Liem, R Gyurek, M Tatipamula, O Gerstel, Cisco Systems , United States, A Banerjee , L Mao , E McGinnis , O Jerphagnon , Calient Networks , United States
We demonstrate a multi-vendor network with various optical switching technologies and client devices emulating a real-world environment. End-to-end and automated provisioning is achieved using standard-based GMPLS control plane and a proprietary optical transmission control plane.
Experiments on Optical Link Capacity Adjustment for Photonic IX
I Shake , M Fukutoku , O Moriwaki, Y Tsukishima, W Imajuku, NTT Corporation , Japan , T Kurahashi, Internet Initiative Japan Inc., Japan , Y Tarui , Internet Multifeed Co., Japan
We successfully applied an optical link capacity adjustment technique to photonic IX experiments for the first time. This technique uses traffic monitoring and path creation/deletion on a control plane of an over-lay model. The experiments show the feasibility of applying the technique to a photonic IX using OXCs and the GMPLS framework.
Tu3.4.4 15:00 – 15:15
Dynamic Bandwidth Modification for L2 Switches by Interacting with Traffic Monitoring and GMPLS Control Plane
T Tsuritani , M Miyazawa, T Otani, H Tanaka, KDDI R&D Laboratories Inc. , Japan
A dynamic bandwidth management for L2SWs in GMPLS networks has been firstly proposed and demonstrated. The number of lambda-paths between L2SWs has been successfully controlled by interacting with traffic monitoring and GMPLS control plane.
Migration of a GMPLS Network into an Existing IP/MPLS Network by Border-Peer Router Model
K Ogaki , T Otani, H Tanaka, KDDI R&D Laboratories Inc. , Japan , M Tatipamula, Z Ali, Cisco Systems Inc. , United States , K Kumaki, KDDI Corporation , Japan
Migration of a GMPLS network into an IP/MPLS network using border-peer router model was proposed and successfully demonstrated without sacrificing the existing IP/MPLS network's routing instance and addressing, while ensuring GMPLS interoperability.
Tu3.4.6 15:30 – 15:45
Experimental in-Fibre GMPLS Fault Management for 1:1 OUPSR R-OADM Networks
R Muñoz , R Martinez, C Pinart, Centre Tecnoloògic de Telecomunicacions de Catalunya (CTTC) , Spain, J Sorribes , G Junyent, Universitat Politècnica de Catalunya (UPC), Spain
This paper presents a novel GMPLS-based signalling for fault management in 1:1 OUPSR rings tested in the ADRENALINE testbed that solves some lacks of Link Management Protocol for out-of-band in-fibre IP control channels
Alsh Room
Tu3.5 – All-Optical Logic
Chair: Tony Kelly, University of Glasgow, United Kingdom
Tu3.5.1 14:00 – 14:15
All-Optical 40Gb/s Logic XOR Gate with Dual Ultrafast Nonlinear Interferometers
R P Webb , X Yang , R J Manning , R Giller , University College Cork , Ireland
We propose and demonstrate at 40Gb/s a novel XOR logic gate using dual cascaded ultrafast nonlinear interferometer (UNI) elements based on semiconductor optical amplifiers. The potential speed is higher than for previously demonstrated XOR gates.
Tu3.5.2 14:15 – 14:30
Demonstration of an All-Optical Three-Input Exclusive-OR Logic Gate for High-Speed Optical DPSK Signals
N Deng , C-K Chan , L K Chen , The Chinese University of Hong Kong , China
An all-optical exclusive-OR logic gate for three-input 10-Gb/s optical DPSK signals is demonstrated via four-wave mixing in a single semiconductor optical amplifier. Its logic integrity and performance are experimentally evaluated by BER measurements.
Tu3.5.3 14:30 – 14:45
All-Optical Logic Gates Based on an SOA and an Optical Filter
Z Li , Y Liu , S Zhang , H Ju , H de Waardt , G D Khoe , Eindhoven, University of Technology , The Netherlands, D
Lenstra , Vrije Universiteit , The Netherlands
A novel all-optical logic device, composed of an SOA and an optical filter, is demonstrated for AND, OR and XOR gates at 10 Gb/s. Simulation indicates the device can operate at higher bit rate.
Tu3.5.4 14:45 – 15:00
Experimental Investigation of Pattern-Dependent Phase Fluctuation in Wavelength Conversion and XOR Operation Using Semiconductor Optical Amplifiers
I Kang , C Dorrer , L Zhang , A Bhardwaj, L Buhl, M Dinu, D T Neilson, M Rasras , S Cabot , M Cappuzzo , L Gomez , A Wong-Foy , Y F Chen , S Patel, J Jaques, Bell Laboratories, Lucent Technologies , United States
We measure the phase dynamics and statistics of SOA-based wavelength conversion and XOR operation using linear optical sampling. We elucidate the role of the pattern dependent phase fluctuation in limiting the performance of XOR operation.
Tu3.5.5 15:00 – 15:15
Optical Shift Register Based on an Optical Flip-Flop Memory with a Single Active Element
S Zhang , Z Li , Y Liu , R Geldenhuys , H Ju , G D Khoe, H J S Dorren, Eindhoven University of Technology, The Netherlands , D Lenstra, Vrije Universiteit , The Netherlands
We present an optical shift register consisting of two serially connected optical flip-flop memories. The concept is demonstrated experimentally using fibre pig-tailed components.
Tu3.5.6 15:15 – 15:30
1.3µm Optical Encoder/Correlators on GaAs-based Photonic Integrated Circuits
K Koyama , J Hashimoto, Y Tsuji, T Katsuyama, A Ishida , Sumitomo Electric Industries , Ltd., Japan
We present monolithic optical encoder/correlators consisting GaInNAs-SOAs and GaAs waveguide circuits. The 4-bit coding and correlating operations at 1310nm are successfully demonstrated with transmission of SMF 40km.
Tu3.5.7 15:30 – 15:45
Bandwidth Enhancement of SOA-Based Switches Using Optical Filtering: Theory and Experiment
M L Nielsen , J Mørk , Technical University of Denmark, Denmark
We present the first small-signal response measurements on an all-optical DISC switch, and verify theoretical predictions of the large modulation bandwidth enhancing effect of optical filtering after an SOA.
Boisdale Room
Tu3.6 – Silicon and High Index Contrast Integrated Components
Chair: Edwin Pun, City University of Hong Kong, Hong Kong
Tu3.6.1 14:00 – 14:30
Invited - All-Optical and Electro-Optical Control of Light on a Silicon Chip
M Lipson, Cornell University, United States
We demonstrate strong light confining micron-size structures including cavities with V eff on the order of 10 -2 ( 
n)-3. The strong confinement structures enables active devices on silicon such as low power modulators and bistable switches.
Tu3.6.2 14:30 – 15:00
Invited - Recent Progress in SOI Nanophotonic Waveguides
D Van Thouthout, P Dumon, W Bogaerts, G Roelkens, D Taillaert, G Priem, R Baets, IMEC-Ghent University, Belgium
Submicron Silicon wire waveguides allow realising extremely compact photonic ICs and can be fabricated in a cost-effective and reliable manner. We demonstrate basic waveguide functions and results for more complex WDM-devices.
Tu3.6.3 15:00 – 15:15
Reconfigurable Optical Add-Drop Multiplexer Based on Silicon Nano-Wire Waveguides
T Chu , H Yamada , Optoelectronic Industry and Technology Development Association (OITDA) , Japan , S Ishida , Y Arakawa , T he University of Tokyo , Japan
A reconfigurable optical add-drop multiplexer with Bragg-grating-reflectors based on silicon nano-wire waveguides was demonstrated by tuning the dropping wavelength through thermo-optic effect. The channel passband and the channel isolation were 1-nm and 18-dB, respectively.
First Demonstration of a Semiconductor-Integrated Optical Digital-to-Analog Converter
H Uenohara , R Kurosawa, Tokyo Institute of Technology , Japan
Semiconductor-integrated optical digital-to-analog converter was realized for the first time. Two-bits four-level analog signals were generated and the phase error of about ±0.095 p was observed.
Tu3.6.5 15:30 – 15:45
A Compact Fibre-to-Waveguide Coupler Based on Angled Slots.
F Van Laere , D Taillaert, D Van Thourhout, R Baets, Ghent University - IMEC , Belgium , M V Kotlyar , T F Krauss , University of St. Andrews, United Kingdom
We present a compact grating coupler, consisting of slanted air slots, for coupling from single-mode fiber to InP-based waveguides. The theoretical coupling efficiency is better than 50% and first fabrication experiments are promising.
Tuesday, 27 September – 4 th Quarter Regular Sessions (16:15 – 18:00)
Lomond Auditorium
Tu4.2 – Electronic Mitigation of Impairments II
Chair: Michel Joindot, France Telecom R&D/RTA, France
Tu4.2.1 16:15 - 16:45
Invited - Electronic Precompensation Techniques to Combat Dispersion and Nonlinearities in Optical Transmission
R Killey, P Watts, P Bayvel, University College London, United Kingdom , M Glick, Intel Research, United Kingdom
The impact of fibre nonlinearity on the performance of systems employing electronic precompensation is discussed, and the results of simulations demonstrating the simultaneous compensation of dispersion and intrachannel nonlinearities in 10 Gb/s transmission are presented.
Tu4.2.2 16:45 – 17:00
Electronic Pre-Distortion for Advanced Modulation Formats
P J Winzer , R-J Essiambre , Bell Labs, Lucent Technologies , United States
We discuss implementation and scaling aspects of electronic pre-distortion transmitters combating chromatic dispersion. We present results for a variety of optical amplitude and phase modulation formats.
Tu4.2.3 17:00 – 17:15
Performance Enhancement for Duobinary Modulation Through Nonlinear Electrical Equalization
C Xia , W Rosenkranz , University of Kiel , Germany
A nonlinear electrical equalization technique is proposed to improve the performance in optical duobinary modulation system. We show that more than 1000ps/nm dispersion tolerance improvement and comparable performance to MLSE equalizer can be achieved.
Tu4.2.4 17:15 – 17:30
Performance of Optical Single Sideband Signal Transmission Systems Using Adaptive Electronic Dispersion Compensators
PM Watts , V Mikhailov, P Bayvel, R I Killey, University College London , United Kingdom , M Glick , Intel Research Cambridge , United Kingdom
The performance of adaptive FIR electronic filters for chromatic dispersion compensation in optical single sideband systems was investigated by numerical simulations. 10 Gb/s transmission over 720 km of standard single mode fibre was demonstrated.
Tu4.2.5 17:30 – 17:45
Laser FM Noise Impact on DCF-Free Transmission Utilising Electronic Dispersion Compensation
R A Griffin , G Busico , Bookham , United Kingdom
The impact of laser FM noise on transmission beyond the conventional dispersion limit is studied for OOK and DPSK formats, analysing the performance of full-band tunable multi-section DBR lasers.
Tu4.2.6 17:45 – 18:00
Accurate Digital Phase Estimation Process for Coherent Detection Using a Parallel Digital Processor
M G Taylor , University College London , United Kingdom
A phase estimation method is presented and demonstrated experimentally which is suitable for coherent detection of signals using a parallel digital processor. The method achieves an estimate within 0.1dB of the MAP estimate.
Argyll Suite
Tu4.3 – Network Design
Chair: Andreas Gladisch, T-Systems, Germany
Tu4.3.1 16:15 – 16:45
Invited - Multi-Layered Photonic Network Design Considering Incremental Traffic Growth and Different Service Contract Terms
K Kanie , H Hasegawa , K Sato , Nagoya University , Japan
We propose a quasi-dynamic multi-layered photonic network design that achieves cost-effective incremental expansion to accommodate future broadband services. With several design examples, we give an organized perspective of such a design to optimize the network cost.
Demonstration of PCE-Controlled Dynamic Traffic Engineering for GMPLS-Based Multilayer Service Network
T Miyamura , T Kurimoto , R Hayashi , I Inoue , K Shiomoto , S Urushidani , NTT Network Service Systems Laboratories, Japan
A traffic engineering system based on MLSN architecture was firstly developed by implementing PCE providing multilayer path computation and path control. Dynamic multilayer IP/Optical topology reoptimization based on measured traffic was successfully demonstrated.
Tu4.3.3 17:00 – 17:15
Emulation of Overspill Routing in Optical Networks
E Van Breusegem , J Cheyns, D Colle, M Pickavet, P Demeester, Ghent University - IMEC , Belgium , D De Winter , J Moreau, Hogeschool Ghent , Belgium
Overspill routing in optical networks, ORION, is a network architecture combining lower IP switching capacity requirements with high bandwidth efficiencies. We present results from an ORION emulation platform, which is fully compatible with GMPLS.
Tu4.3.4 17:15 – 17:30
Dynamic vs. Static Lightpath Allocation in WDM Networks
A Zapata , Universidad Técnica Federico Santa María , Chile & University College London , United Kingdom , P Bayvel , University College London , United Kingdom
Dynamic and static WDM networks are compared in terms of wavelength requirements. Results show that low physical network connectivity and wavelength conversion capability are key in reducing the wavelength requirements in dynamic optical networks
Tu4.3.5 17:30 – 17:45
Fast Segmented-Path Restoration Using TCM-Based Fault Detection and OTN Signalling for GMPLS Optical Transport Networks
Y Fukashiro , T Hirai, H Tsushima, Hitachi Communication Technologies, Ltd. , Japan , K Kusama , Systems Development Laboratory, Hitachi Ltd, Japan
OTN signalling-based fast segmented path restoration of a dynamic path established by GMPLS has been demonstrated. A ODU2 path was restored with a recovery time of 30ms using newly adopted TCM-based fault detection technique.
Tu4.3.6 17:45 – 18:00
Hybrid Protection in WDM Networks with Shared Risk Link Groups
X Shao , L Zhou, X Cheng, Y Wang, Institute for Infocomm Research , Singapore , G Xiao , Nanyang Technological University , Singapore
In networks with shared risk link groups, path protection may have severe traps and sometimes, extra-long backup paths. We propose a new protection scheme which efficiently solves these problems by combining path and link protections.
Forth Room
Tu4.4 – Microstructured Fibres II
Chair: Tim Birks , University of Bath, UK
Tu4.4.1 16:15 – 16:45
Invited - Reducing the Losses in Photonic Crystal Fibres
K Kurokawa, K Tajima, K Tsujikawa, K Nakajima, NTT Access Network Service Systems Laboratories, Japan
Photonic crystal fibres (PCF) are attractive transmission media since they have many unique features that are not available with a conventional SMF. We describe recent progress on low loss PCFs and their application to optical transmission.
Tu4.4.2 16:45 – 17:00
Penalty-free 10 Gb/s Transmission in 1.0 µm Band over 24 km Low Loss PCF
K Tsujikawa , K Kurokawa, K Tajima, K Nakajima, T Matsui, I Sankawa, NTT Access Network Service Systems Laboratories , United Kingdom
We successfully fabricated a low loss (0.9 dB/km at 1064 nm) PCF, and achieved the first penalty-free 10Gb/s transmission in a new optical window of 1.0 µm over 24 km by using the pre-chirp technique.
Tu4.4.3 17:00 – 17:15
Distributed Raman Amplification at 850 nm in a Low Loss Photonic Crystal Fibre
K Nakajima , C Fukai, K Kurokawa, K Tajima, T Matsui, I Sankawa, NTT Access Network Service Systems Laboratories , Japan
We have demonstrated a distributed Raman amplification at 850 nm for the first time utilizing a low loss photonic crystal fibre. Power penalty has been improved by 1.6 dB in 6.0 km transmission.
Tu4.4.4 17:15 – 17:30
Microstructured Fibres for High Power Beam Delivery Applications
E J O'Driscoll , M A Watson, T Delmonte , BAE SYSTEMS, United Kingdom, M N Petrovich, V Finazzi , J C Baggett , D J Richardson, University of Southampton , United Kingdom, T M Monro , University of Adelaide , Australia
We explore the potential offered by solid and air core microstructured fibres for high power applications and report the use of these fibre types in a pump delivery system for an optical parametric oscillator (OPO).
Tu4.4.5 17:30 – 17:45
Enhancement of Nonlinear Effect in Tellurite Photonic Crystal Fibre Realized by Amplification with Er3+
S Aozasa , A Mori , M Kato , K Oikawa , M Yamada , K Naganuma , H Ono , NTT Corporation , Japan
We confirmed that amplification employing Er3+ enhances the nonlinear effect of tellurite photonic crystal fibre, and demonstrated the possibility of highly efficient wavelength conversion with a short fibre length.
Tu4.4.6 17:45 – 18:00
Widely Tunable Wavelength Conversion with Extinction Ratio Enhancement Using PCF Based NOLM
C H Kwok , S H Lee , K K Chow , C Shu, C L Lin, The Chinese University of Hong Kong , Hong Kong
Widely tunable wavelength conversion has been demonstrated using a 64-m-long dispersion-flattened photonic crystal fiber in a nonlinear optical loop mirror. The output extinction ratio can be maintained above 13-dB over 60-nm.
Alsh Room
Tu4.5 – Semiconductor Laser Diodes
Chair, Piero Gambini , Agilent Technologies, Italy
Tu4.5.1 16:15 – 16:30
A 1310-nm InGaAlAs Short-Cavity DBR laser for 100ºC, 10-Gbit/s Operations with a 14-mApp Current Drive
M Aoki , K Shinoda , T Kitatani , T Tsuchiya , Hitachi Ltd. , Japan, M Mukaikubo , K Uchida , K Uomi , Opnext Japan Inc , Japan
We propose and demonstrate a new 1310-nm DBR-based InGaAlAs short-cavity edge-emitter suitable for cost-effective 10-Gbit/s smaller-form-factor modules. We achieved 100ºC, 10-Gbit/s direct-modulations at a record 14-mAp-p current-drive with an averaged chip-power of -3 dBm.
Tu4.5.2 16:30 – 16:45
Ru-doped Semi-Insulating Buried Heterostructure Laser Operating up to 100 °C for 10-Gbit/s Direct Modulation
R Iga , Y Kondo , T Takeshita , K Kishi , M Yuda , NTT Photonics Labs. , Japan
We report the high-temperature characteristics of 1.3-µm InGaAsP directly modulated lasers with a simple buried structure using Ru-doped semi-insulating InP. Clear eye openings under 10-Gbit/s direct modulations were obtained from 0 to 100 °C.
Tu4.5.3 16:45 – 17:00
Experimental Evaluation of Carrier Transport, Gain, T0 and Chirp of 1.55 µm MQW Structures with Different Barrier Compositions
M N Akram , R Schatz , S Marcinkevicius , O Kjebon , J Berggren , Royal Institute of Technology , Sweden
Direct carrier transport measurements were performed for different InGaAsP/InGaAlAs MQW test structures. Shallow InGaAlAs barrier QW showed faster carrier transport. Semi-insulating regrown FP lasers with InGaAlAs barrier QW showed improved high temperature operation, modal gain, differential modal gain and chirp.
Tu4.5.4 17:00 – 17:15
High Single-Mode Yield, Tapered 1.55 µm DFB Lasers for CWDM Applications
M Möhrle , A Sigmund , A Suna , L Mörl , W Fürst , A Dounia , W-D Molzow , Fraunhofer Institute Nachrichtentechnik, Heinrich-Hertz-Institute , Germany
A novel type of index-coupled DFB-lasers is presented. The lasers feature low threshold current, low beam divergence, a -3 dB cut-off frequency of 11 GHz at 90°C, and high single mode yield even as-cleaved.
Tu4.5.5 17:15 – 17:30
High Power InAs/GaInAs Quantum Dot Lasers with Enhanced Temperature Stability for Uncooled Pump Applications
R Debusmann , S Deubert , A Forchel, University of Wuerzburg , Germany , J P Reithmaier , University of Kassel , Germany
High power quantum dot lasers with increased temperature stability of the emission wavelength were realized suitable for uncooled pump applications for fibre amplifiers. By tailoring the QD ensemble we could reduce the temperature coefficient to 0.1 nm/K.
Tu4.5.6 17:30 – 17:45
High-Power and High-Brightness Lasers with an Al-free Active Region at 915 nm.
N Michel , M Calligaro , M Lecomte , O Parillaud , M Krakowski , Thales Research and Technology & Alcatel Thales III-V Lab , France , L Borruel , I Esquivias , P Moreno , Universidad Politécnica de Madrid , Spain, J Wykes , E C Larkins , U niversity of Nottingham , United Kingdom
We have developed Al-free broad area lasers with low optical losses of 0.5 cm-1 and T0 = 171 K. Clarinet lasers deliver 0.65 W CW with an M² of less than 1.3 at 1/e².
Tu4.5.7 17:45 – 18:00
Ultralow Threshold Long Wavelength Single-Mode Quantum Dot VCSELs on GaAs Substrates
C Möller , S S Mikhrin , A V Kozhukhov , I L Krestnikov , D A Livshits , A R Kovsh , N N Ledentsov , NL Nanosemiconductor GmbH , Germany, H J Hensel, W D Molzow, R Gibis, D Schmidt, A Paraskevopoulos, Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institut,
Quantum dots provide an opportunity to achieve ultralow threshold current (210 µA, 9.5µm x 9.5µm oxide aperture) all-semiconductor DBR GaAs VCSELs operating single mode in the 1.3µm wavelength range.
Boisdale Room
Tu4.6 – Bragg Gratings and UV Poling
Chair: Walter Margulis , Acreo, Sweden
Tu4.6.1 16:15 – 16:30
A Matrix of Poling Evolution Data Showing the Effects of Voltage and Temperature in Optical Fibre and a Numerical Model Comparison
K Lee , J Blows, S Fleming , University of Sydney, Australia
We present the first experimental poling evolution data in fibre for a range of poling voltages and poling temperatures. The evolution curves are then reproduced with a two charge numerical model with good accuracy.
Tu4.6.2 16:30 – 16:45
Application of a Conductive Polyimide Coating in Thermal Poling of Long Lengths of Fibre
K Lee , P Hu, J Blows, S Fleming, S Fleming , University of Sydney, Australia
We have poled fibre with a single internal electrode and an external electrode that is a conductive polyimide coating, enabling manufacture of long lengths of poled fibre, with electrodes incorporated solely during the draw process.
Tu4.6.3 16:45 – 17:00
UV Poling of Pure Fused Silica by High-Intensity Femtosecond Radiation
C Corbari , P G Kazansky, University of Southampton , United Kingdom, S A Slattery, D N Nikogosyan, University College Cork , Ireland
We demonstrated UV poling of a pure fused silica sample by applying to it an electric field of 200 kV/cm and irradiating it with high-intensity (~200 GW/cm2) femtosecond (220 fs) laser pulses at 264 nm.
Tu4.6.4 17:00 – 17:15
A Novel XPM Based Pulse Retiming System Incorporating a Fibre Grating Based Parabolic Pulse Shaper
F Parmigiani , P Petropoulos , M Ibsen , M A F Roelens , D J Richardson, University of Southampton , United Kingdom
A novel all-optical, all-fibre pulse retiming system is experimentally demonstrated. Our technique relies on converting the timing jitter into frequency shift using XPM switching of the data signal with parabolic pulses shaped using a SSFBG.
Tu4.6.5 17:15 – 17:30
Full Characterisation of the Temporal Response of Complex Phase Shifted Bragg Gratings for OCDMA Using Frequency Resolved Optical Gating
M A F Roelens , C Tian , Z Zhang , P Petropoulos , M Ibsen , D J Richardson, University of Southampton , United Kingdom
We report on the use of frequency resolved optical gating based on sampling with an electro-absorption modulator to characterise the phase and intensity of multichip encoded OCDMA pulses generated with fibre Bragg gratings.
Tu4.6.6 17:30 – 17:45
Co-Propagating Cladding Modes Coupling Assisted by Tilted Bragg Grating with Large Tilting Angle
K Zhou , X Chen , L Zhang , I Bennion , Aston University , United Kingdom
We report for the first time forward propagating cladding modes coupling by using tilted gratings. The spectral responses of these gratings were investigated and their thermal characteristics and sensitivity to environmental refractive index were evaluated.
Tu4.6.7 17:45 – 18:00
All-Fibre Dual-Direction Gires-Tournois Etalon Realized with Single Complex Fiber Bragg Grating Structure
X Shu , K Sugden , Ian Bennion , Aston University , United Kingdom
We propose and demonstrate a novel single fibre Bragg grating based Gires-Tournois (GT) etalon, which is realized by applying a complex apodisation profile on a linearly chirped fibre Bragg grating. Such a GT etalon not only has simplified fabrication procedure but also can operate in dual directions.