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1.
Opt Express ; 31(20): 31898-31911, 2023 Sep 25.
Article in English | MEDLINE | ID: mdl-37859004

ABSTRACT

We address the potential application of G.654.C optical fiber for O-band transmission in the wavelength range of 1270 nm to 1330 nm. Fiber samples at the extreme upper end of the cable cutoff manufacturing distribution are chosen for modeling and experimentation. Modeling of multipath interference (MPI) generation in bend conditions representative of cable deployment suggests minimal to negligible penalty and transmission experiments at 100 Gb/s and 400 Gb/s with commercial IMDD transceivers demonstrate longer transmission with increased power margin compared to standard G.652 fiber due to lower O-band attenuation and no adverse impacts from MPI.

2.
BMJ Case Rep ; 14(7)2021 Jul 19.
Article in English | MEDLINE | ID: mdl-34281940

ABSTRACT

The formation of a light scattering interlenticular membrane (ILM) is a known complication of polypseudophakia and has been particularly noted with the use of dual intracapsular Alcon AcrylSof intraocular lenses (IOLs). The treatment options for this condition have largely been restricted to either Nd:YAG laser membranotomy or explantation of the dual IOL complex. In this case report, we describe an unusual case of ILM in a 76-year-old woman whose ILM had formed between her primary intracapsular IOL and her piggyback sulcal IOL. Furthermore, we describe vitreoretinal interlenticular membranectomy (VIM), a novel technique involving a translimbal anterior interlenticular membranectomy using vitreoretinal instrumentation. There were no intraoperative or postoperative complications. Postoperative best-corrected visual acuity was 6/4, maintained for 3 years of follow-up. VIM is offered as a management option for surgeons to address ILM when Nd:YAG laser therapy fails, and the IOLs cannot be safely explanted.


Subject(s)
Cataract , Lenses, Intraocular , Aged , Device Removal , Female , Humans , Postoperative Complications , Postoperative Period
3.
J Asthma Allergy ; 14: 381-392, 2021.
Article in English | MEDLINE | ID: mdl-33907423

ABSTRACT

BACKGROUND: Tezepelumab is an anti-thymic stromal lymphopoietin monoclonal antibody in development for the treatment of severe asthma. This study assessed the functionality and performance of an accessorized pre-filled syringe (APFS) and an autoinjector (AI) for administration of tezepelumab in the clinic and at home. METHODS: This phase 3, multicenter, randomized, open-label, parallel-group study (PATH-HOME, ClinicalTrials.gov identifier: NCT03968978) was conducted in patients aged 12-80 years with asthma that was uncontrolled despite treatment with medium- to high-dose inhaled corticosteroids plus at least one additional controller medication. Patients received six subcutaneous doses of tezepelumab 210 mg via APFS or AI. The first dose was administered by a healthcare professional, and patients or caregivers administered subsequent doses. First, second, third and final doses were administered in the clinic; fourth and fifth doses were administered at home. The primary endpoint was the proportion of successful administrations of tezepelumab. Secondary endpoints included the functionality and performance of the devices, Asthma Control Questionnaire (ACQ)-6 score, pharmacokinetics and safety. RESULTS: Overall, 216 patients were randomized (APFS, n=111; AI, n=105). Tezepelumab was successfully administered via APFS by 91.7% of the participants (100/109) and via AI by 92.4% (97/105). Overall, 95.4-97.1% of at-home administrations were successful across device groups. Malfunction occurred in 6 of 655 dispensed APFSs and 5 of 624 dispensed AIs. Clinically meaningful improvements in ACQ-6 score were observed after 24 weeks in 81.1% and 76.2% of the patients in the APFS and AI groups, respectively. Tezepelumab pharmacokinetics were consistent between device groups and with previous studies. The most common adverse event was nasopharyngitis (9.3%). Injection-site reactions occurred in 5.7% and 0% of the patients in the AI and APFS groups, respectively. CONCLUSION: This study demonstrated that the APFS and AI were functional and reliable, and performed equally well at home and in the clinic.

4.
Int J Surg Case Rep ; 79: 368-370, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33516052

ABSTRACT

INTRODUCTION AND IMPORTANCE: A Superficial Temporal Artery Pseudoaneurysm is an uncommon, but important, differential diagnosis for masses in the head and neck region. This work has been reported in line with SCARE 2020 criteria [1]. CASE PRESENTATION: An 81-year-old male presented to the Oral and Maxillofacial Department with a facial swelling that had been present for a duration of three weeks. A provisional diagnosis of a haematoma was made and an ultrasound carried out to confirm diagnosis. Ultrasonography and CT Angiography confirmed a pseudoaneurysm arising from the left superficial temporal artery. CLINICAL DISCUSSION: Although this is a relatively uncommon diagnosis it is important to be aware of the key diagnostic tools used to identify a pseudoaneurysm. Specifically, their potential to exclude a pseudoaneurysm prior to diagnosing a simple post-traumatic haematoma. This is important as the treatment strategies for the two pathologies differ considerably. Useful learning points from this case include diagnostic aids such as the unique pulsatile nature of the mass and the role of ultrasonography and CT Angiography in confirming diagnosis and guiding surgical management. CONCLUSION: Pseudoaneurysms are an important consideration as a differential diagnosis of masses in the head and neck region. This case report may impact upon management of future similar cases by highlighting significant aspects of their clinical diagnosis and surgical management, enabling early identification and appropriate management.

5.
Clin Ther ; 43(1): 142-155.e5, 2021 01.
Article in English | MEDLINE | ID: mdl-33380362

ABSTRACT

PURPOSE: Tezepelumab is an anti-thymic stromal lymphopoietin monoclonal antibody therapeutic in development for patients with severe, uncontrolled asthma. In ongoing Phase III studies, tezepelumab is administered via subcutaneous (SC) injections using a vial-and-syringe (V-S). This study compared the pharmacokinetic (PK) parameters, safety, and tolerability of tezepelumab administered subcutaneously via V-S versus via an accessorized prefilled syringe (APFS) or autoinjector (AI). METHODS: This single-center, randomized, open-label, parallel-group study was conducted in healthy volunteers aged 18-65 years. Participants, stratified according to weight (50 to <70 kg, 70 to <80 kg, or 80-90 kg), were randomized evenly to 9 groups representing injections to the abdomen, thigh, or upper arm via V-S, APFS, or AI. Tezepelumab PK parameters over 113 days were evaluated after a single 210-mg SC dose. The primary end points were comparison of Cmax and AUC0-∞ between device groups. Further PK parameters, immunogenicity, safety (including injection site reactions [ISRs] and injection site pain [visual analog scale]) were also assessed. FINDINGS: A total of 315 adults were randomized to treatment. Geometric mean ratios for comparisons between device groups of Cmax, AUC0-∞, and AUC0-last were close to 1, with 90% CIs all within the range of 0.8-1.25, meeting bioequivalence criteria. PK variables were also similar between devices across injection sites and weight categories. Across devices, thigh injection resulted in slightly higher exposure than upper arm injection, and abdomen injection resulted in exposure similar to or slightly lower than thigh injection; however, these differences were not clinically meaningful. Treatment-emergent anti-tezepelumab antibodies were present in 3 (2.9%), 1 (1.0%), and 0 participants in the V-S, APFS, and AI groups, respectively. Treatment-related adverse events were reported in 15.0% of participants overall (V-S, 10.7%; APFS, 18.1%; AI, 16.0%), including ISRs in 1 (1.0%), 3 (2.9%), and 3 (2.8%) participants in the V-S, APFS, and AI groups. Median visual analog scale pain score (0-100 mm scale) was 2 mm immediately after injection and was 0 mm at 30 min for all groups. IMPLICATIONS: Tezepelumab PK parameters after a single 210-mg SC dose were comparable when administered via V-S, APFS, or AI. In all groups, immunogenicity rate and injection site pain were low, and ISRs were uncommon. These findings support administration of tezepelumab via APFS or AI, in addition to V-S, providing patients and physicians with greater choice and the potential convenience of at-home use. ClinicalTrials.gov identifier: NCT03989544.


Subject(s)
Anti-Asthmatic Agents/administration & dosage , Antibodies, Monoclonal, Humanized/administration & dosage , Adult , Anti-Asthmatic Agents/adverse effects , Anti-Asthmatic Agents/pharmacokinetics , Antibodies, Monoclonal, Humanized/adverse effects , Antibodies, Monoclonal, Humanized/pharmacokinetics , Drug Delivery Systems , Female , Healthy Volunteers , Humans , Injections, Subcutaneous , Male , Middle Aged , Pain Measurement , Syringes
6.
Respir Res ; 21(1): 279, 2020 Oct 21.
Article in English | MEDLINE | ID: mdl-33087119

ABSTRACT

BACKGROUND: Tezepelumab is a human monoclonal antibody that blocks the activity of the epithelial cytokine thymic stromal lymphopoietin. The efficacy, safety and oral corticosteroid-sparing potential of tezepelumab are being investigated in two ongoing, phase 3, randomized, double-blind, placebo-controlled studies (NAVIGATOR [NCT03347279] and SOURCE [NCT03406078]). DESTINATION (NCT03706079) is a long-term extension (LTE) of these studies. METHODS: DESTINATION is a randomized, double-blind, placebo-controlled LTE study in adults (18-80 years old) and adolescents (12-17 years old) with severe, uncontrolled asthma who are receiving treatment with medium- or high-dose inhaled corticosteroids plus at least one additional controller medication with or without oral corticosteroids. The study population will comprise patients who complete the 52- and 48-week NAVIGATOR and SOURCE studies, respectively. Patients who were randomized to receive tezepelumab 210 mg every 4 weeks (Q4W) in either predecessor study will continue to receive this regimen for 1 year; those who were previously randomized to receive placebo will be re-randomized (1:1) to receive either tezepelumab 210 mg Q4W or placebo for 1 year. Patients will receive their prescribed controller medications throughout DESTINATION and study physicians will have the opportunity to down- or up-titrate dosage of these medications, if appropriate. The primary objective is to evaluate the long-term safety and tolerability of tezepelumab over 104 weeks (inclusive of the treatment period of either predecessor study). The secondary objective is to assess the long-term effect of tezepelumab on asthma exacerbations. Patients recruited from SOURCE will be followed up post-treatment for 12 weeks. Patients recruited from NAVIGATOR who complete 100 weeks of tezepelumab treatment will be eligible for either 12 weeks of follow-up or a 36-week extended follow-up during which the clinical benefit of tezepelumab after treatment cessation will be investigated. DISCUSSION: DESTINATION will evaluate the long-term safety, tolerability and efficacy of tezepelumab versus placebo with continued dosing for up to 2 years. DESTINATION will also evaluate the clinical effect of tezepelumab after treatment cessation. This LTE study aims to elucidate the long-term safety implications of receiving tezepelumab and to assess its potential long-term treatment benefits in patients with severe, uncontrolled asthma. TRIAL REGISTRATION: NCT03706079 (ClinicalTrials.gov). Registered 15 October 2018.


Subject(s)
Anti-Asthmatic Agents/administration & dosage , Antibodies, Monoclonal, Humanized/administration & dosage , Asthma/drug therapy , Severity of Illness Index , Administration, Inhalation , Adolescent , Adrenal Cortex Hormones/administration & dosage , Adrenal Cortex Hormones/adverse effects , Adrenal Cortex Hormones/metabolism , Adult , Aged , Aged, 80 and over , Anti-Asthmatic Agents/adverse effects , Anti-Asthmatic Agents/metabolism , Antibodies, Monoclonal, Humanized/adverse effects , Antibodies, Monoclonal, Humanized/metabolism , Asthma/diagnosis , Asthma/metabolism , Cytokines/metabolism , Double-Blind Method , Drug Therapy, Combination , Female , Follow-Up Studies , Humans , Male , Middle Aged , Young Adult
7.
Respir Res ; 21(1): 265, 2020 Oct 13.
Article in English | MEDLINE | ID: mdl-33050900

ABSTRACT

BACKGROUND: Patients with severe, uncontrolled asthma, particularly those with a non-eosinophilic phenotype, have a great unmet need for new treatments that act on a broad range of inflammatory pathways in the airway. Tezepelumab is a human monoclonal antibody that blocks the activity of thymic stromal lymphopoietin, an epithelial cytokine. In the PATHWAY phase 2b study (NCT02054130), tezepelumab reduced exacerbations by up to 71% in adults with severe, uncontrolled asthma, irrespective of baseline eosinophilic inflammatory status. This article reports the design and objectives of the phase 2 CASCADE study. METHODS: CASCADE is an ongoing exploratory, phase 2, randomized, double-blind, placebo-controlled, parallel-group study aiming to assess the anti-inflammatory effects of tezepelumab 210 mg administered subcutaneously every 4 weeks for 28 weeks in adults aged 18-75 years with uncontrolled, moderate-to-severe asthma. The primary endpoint is the change from baseline to week 28 in airway submucosal inflammatory cells (eosinophils, neutrophils, T cells and mast cells) from bronchoscopic biopsies. Epithelial molecular phenotyping, comprising the three-gene-mean technique, will be used to assess participants' type 2 (T2) status to enable evaluation of the anti-inflammatory effect of tezepelumab across the continuum of T2 activation. Other exploratory analyses include assessments of the impact of tezepelumab on airway remodelling, including reticular basement membrane thickening and airway epithelial integrity. At the onset of the COVID-19 pandemic, the protocol was amended to address the possibility that site visits would be limited. The amendment allowed for: at-home dosing of study drug by a healthcare professional, extension of the treatment period by up to 6 months so patients are able to attend an onsite visit to undergo the end-of-treatment bronchoscopy, and replacement of final follow-up visits with a virtual or telephone visit. DISCUSSION: CASCADE aims to determine the mechanisms by which tezepelumab improves clinical asthma outcomes by evaluating the effect of tezepelumab on airway inflammatory cells and remodelling in patients with moderate-to-severe, uncontrolled asthma. An important aspect of this study is the evaluation of the anti-inflammatory effect of tezepelumab across patients with differing levels of eosinophilic and T2 inflammation. TRIAL REGISTRATION: NCT03688074 (ClinicalTrials.gov). Registered 28 September 2018.


Subject(s)
Anti-Asthmatic Agents/therapeutic use , Anti-Inflammatory Agents/therapeutic use , Antibodies, Monoclonal, Humanized/therapeutic use , Asthma/drug therapy , Adolescent , Adult , Aged , Anti-Asthmatic Agents/adverse effects , Anti-Inflammatory Agents/adverse effects , Antibodies, Monoclonal, Humanized/adverse effects , Asthma/diagnosis , Asthma/immunology , Clinical Trials, Phase II as Topic , Double-Blind Method , Female , Humans , Male , Middle Aged , Multicenter Studies as Topic , Randomized Controlled Trials as Topic , Treatment Outcome , Young Adult
8.
Article in English | MEDLINE | ID: mdl-30666852

ABSTRACT

PURPOSE: To evaluate the efficacy and safety of early pars plana vitrectomy (PPV) for the treatment of acute infective endophthalmitis, and identify prognostic factors for better visual outcome. DESIGN: Retrospective cohort study. METHODS: Consecutive patients who underwent early PPV within 72 hours of presentation for the treatment of acute infective bacterial endophthalmitis and presented to a large tertiary referral center in New South Wales, Australia, between January 2009 and December 2013 were included. Changes in best-corrected visual acuity (VA) from baseline to 1 year were examined. RESULTS: A total of 64 patients were included. The inciting events were cataract surgery (53%), intravitreal injection (36%), trabeculectomy (3%), and endogenous (3%). The mean VA improved from 3.1 logMAR (hand motion) at baseline to 1.02 (approximately 20/200) at 1 year, with 42% achieving final VA equal to or better than 0.477 logMAR (20/60) following early PPV. Positive prognostic factors were negative microbial cultures (P < 0.01) and etiology of post-cataract surgery (P < 0.01). In multivariable analyses adjusting for age and prognostic factors, patients with baseline VA of light perception and hand motion achieved greater visual gains than those with counting fingers, with gains of logMAR of -2.68, -2.09, and -0.85, respectively (P < 0.0001). CONCLUSIONS: Most patients who undergo early PPV experience substantial VA improvement. Negative microbial cultures and endophthalmitis after cataract surgery were associated with better final visual outcome. Patients with presenting VA of light perception or hand motion achieved higher visual gains than those with counting fingers, suggesting the possibility that early PPV may be beneficial in both groups.


Subject(s)
Endophthalmitis/surgery , Eye Infections, Bacterial/surgery , Vitrectomy/methods , Aged , Aged, 80 and over , Endophthalmitis/microbiology , Eye Infections, Bacterial/microbiology , Female , Humans , Male , Middle Aged , Multivariate Analysis , Retrospective Studies , Risk Factors , Visual Acuity
9.
Opt Express ; 26(16): 20507-20518, 2018 Aug 06.
Article in English | MEDLINE | ID: mdl-30119360

ABSTRACT

Evolution of next generation wireless networks brings challenges to efficiently transmit a large amount of data from a base station to a remote antenna unit. We investigate a space division multiplexing technique that employs few mode fibers (FMFs) to transmit 3 × 3 MIMO wireless signals, aiming to employ a common digital signal processing (DSP) unit to equalize both the fiber and wireless channel. We optimize system parameters and obtain above 28 dB and 23 dB signal-to-interference and noise ratio (SINR) for 3 meters wireless systems with 500 m and 2 km FMF, which correspond to the transmission capacity of 578 Mb/s and 468 Mb/s using a 20 MHz bandwidth, respectively. Moreover, we analyze that the nonlinear spectrum distortion due to the combined effect of nonlinearity in the directly modulated laser and the differential mode delay in multimode fibers and validate it by simulations.

10.
Opt Express ; 25(8): 9305-9311, 2017 Apr 17.
Article in English | MEDLINE | ID: mdl-28438006

ABSTRACT

Transmission below the cable cut-off wavelength may be a concern in some systems, especially for an optical supervisory channel (OSC) operating below the signal transmission band in systems built with G.654 fiber. In this work, we constructed a cabled span of G.654-compliant fiber and measured the multipath interference (MPI) generated during propagation through the span at a range of wavelengths below the cable cut-offs of the constituent fibers. Measurements were made under a range of conditions including different splice losses and the presence or absence of higher order mode filters placed around the splices. MPI levels were found to be sufficiently low at wavelengths far below the average cable cut-off such that OSC transmission was penalty-free. We compare the experimental results to modeling predictions and find very good agreement.

11.
Clin Exp Ophthalmol ; 45(2): 135-142, 2017 Mar.
Article in English | MEDLINE | ID: mdl-27564396

ABSTRACT

BACKGROUND: Endogenous Klebsiella pneumoniae endophthalmitis (EKPE) is a well-known entity in South-East Asia. We demonstrate a range of differing clinical features and outcomes of EKPE, and highlight the increasing incidence of EKPE in major centres in Sydney and Melbourne, Australia. DESIGN: Retrospective observational case study and case series in the hospital setting. PARTICIPANTS: Four cases of EKPE. METHODS: EKPE cases from 2005 to 2015 were identified through established endophthalmitis databases as well as hospital-based microbiological searches. MAIN OUTCOME MEASURES: EKPE cases were confirmed with positive K. pneumoniae intraocular samples. RESULTS: Rising trends of EKPE were noted in major centres in Australia. Six eyes of four patients with EKPE from January 2011 to December 2015 are reported. The mean age was 49 years (range 43-58 years). Two patients had bilateral involvement. There were systemic symptoms up to 10 days prior to ocular symptoms. The source of sepsis in all cases was a hepatic abscess. Two patients had diabetes mellitus. Five eyes had hypopyon panuveitis on presentation. All eyes underwent vitrectomy. The patient with the most delayed presentation underwent enucleation following globe perforation. Final best corrected visual acuity (BCVA) in one patient with bilateral EKPE was light perception (LP) only. The other three eyes had BCVA in at least one eye of 6/24 or better. CONCLUSIONS: EKPE is an emerging condition in Australia. Although rare, EKPE is a sight-threatening and potentially life-threatening emergency that can initially present to ophthalmologists. One should suspect EKPE in septic patients with a B-scan showing a vitreous or retinal abscess.


Subject(s)
Endophthalmitis/epidemiology , Eye Infections, Bacterial/epidemiology , Forecasting , Klebsiella pneumoniae/isolation & purification , Adult , Endophthalmitis/microbiology , Eye Infections, Bacterial/microbiology , Follow-Up Studies , Humans , Male , Middle Aged , Morbidity/trends , New South Wales/epidemiology , Retrospective Studies , Victoria/epidemiology
13.
Opt Express ; 23(3): 3156-69, 2015 Feb 09.
Article in English | MEDLINE | ID: mdl-25836174

ABSTRACT

We study long-haul Quasi-Single-mode (QSM) systems in which signals are transmitted in the fundamental modes of a few-mode fiber (FMF) while keeping other system components such as amplifiers and receivers are kept single-moded. The large-effective-area nature of the FMF fundamental modes improves system nonlinear tolerance in the expense of mode coupling along FMF transmissions which induces multi-path interference (MPI) and needs to be compensated. We analytically investigate 6-spatial-polarization mode QSM transmission systems in presence of MPI and show that in the weak coupling regime, the QSM channel is a Gaussian random process in frequency. MPI compensation filters are derived and performance penalties due to MPI and signal loss from higher-order modes are characterized. We also experimentally demonstrate 256 Gb/s polarization multiplexed (PM)-16-QAM QSM transmissions over a record distance of 2600 km with 100-km span using decision directed least mean square (DD-LMS) algorithm for MPI compensation.

14.
Respir Med ; 108(9): 1268-76, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25081651

ABSTRACT

INTRODUCTION: Tiotropium, a once-daily long-acting anticholinergic agent, has been shown to be an efficacious and safe add-on treatment for adults with symptomatic asthma, despite treatment with inhaled corticosteroids (ICS). A large proportion of asthmatic adolescents have symptomatic disease despite a wide range of therapeutic options. We investigated the efficacy and safety of three doses of tiotropium, administered in the evening (via Respimat(®) SoftMist™ inhaler), versus placebo in asthmatic adolescents symptomatic despite ICS treatment. METHODS: This randomised, double-blind, placebo-controlled, incomplete crossover study evaluated once-daily tiotropium 5 µg, 2.5 µg and 1.25 µg versus placebo in three 4-week treatment periods. Primary efficacy end point was change in peak forced expiratory volume in 1 s within 3 h post-dose from baseline (peak FEV1(0-3h)). RESULTS: From 139 enrolled patients, 105 were randomised to receive one of four treatment sequences. Peak FEV1(0-3h) response for tiotropium 5 µg was significantly greater versus placebo (p = 0.0043). Trough FEV1 responses were significantly greater for tiotropium 5 µg (p < 0.00001) and 1.25 µg (p = 0.0134) versus placebo, but not for 2.5 µg (p = 0.0975), while FEV1 area under the curve(0-3h) responses were significant for all doses (p = 0.00001-0.0398). Overall incidence of adverse events was balanced across treatment groups, with no dose-dependent observations. The majority of adverse events were mild to moderate in intensity. CONCLUSION: This first study of tiotropium in adolescents with symptomatic asthma demonstrates that tiotropium is well tolerated and efficacious as add-on to maintenance treatment with ICS. ClinicalTrials.gov identifier; NCT01122680.


Subject(s)
Asthma/drug therapy , Bronchodilator Agents/administration & dosage , Cholinergic Antagonists/administration & dosage , Glucocorticoids/therapeutic use , Scopolamine Derivatives/administration & dosage , Administration, Inhalation , Adolescent , Asthma/physiopathology , Bronchodilator Agents/adverse effects , Bronchodilator Agents/therapeutic use , Child , Cholinergic Antagonists/adverse effects , Cholinergic Antagonists/therapeutic use , Cross-Over Studies , Dose-Response Relationship, Drug , Double-Blind Method , Drug Therapy, Combination , Female , Forced Expiratory Volume/drug effects , Humans , Male , Peak Expiratory Flow Rate/drug effects , Scopolamine Derivatives/adverse effects , Scopolamine Derivatives/therapeutic use , Tiotropium Bromide , Treatment Outcome
15.
Opt Express ; 22(9): 10256-61, 2014 May 05.
Article in English | MEDLINE | ID: mdl-24921729

ABSTRACT

We study unrepeatered transmission of 40x256 Gb/s systems with polarization-multiplexed 16-quadrature amplitude modulation (PM-16QAM) channels using simple coherent optical system configurations. Three systems are investigated with either a homogeneous fiber span, or simple two-segment hybrid fiber designs. Each system relies primarily on ultra-low loss, very large effective area fiber, while making use of only first-order backward pumped Raman amplification and no remote optically pumped amplifier (ROPA). For the longest span studied, we demonstrate unrepeatered 256 Gb/s transmission over 304 km with the additional aid of nonlinear compensation using digital backpropagation. We find an average performance improvement in terms of the Q-factor of 0.45 dB by using digital backpropagation compared to the case of using chromatic dispersion compensation alone for an unrepeatered span system.

16.
Opt Express ; 21(14): 17372-8, 2013 Jul 15.
Article in English | MEDLINE | ID: mdl-23938584

ABSTRACT

We compare the transmission performance of three different optical fibers in separate 256 Gb/s PM-16QAM systems amplified with erbium doped fiber amplifiers (EDFAs) and distributed Raman amplification. The span length in each system is 100 km. The fibers studied include standard single-mode fiber, single-mode fiber with ultra-low loss, and ultra-low loss fiber with large effective area. We find that the single-mode fiber with ultra-low loss and the large effective area fiber with ultra-low loss afford reach advantages of up to about 31% and 80%, respectively, over standard fiber measured at distances with 3 dB margin over the forward error correction (FEC) threshold. The Raman amplified systems provide about 50% reach length enhancement over the EDFA systems for all three fibers in the experimental set-up. For the best performing fiber with large effective area and ultra-low loss, the absolute reach lengths with 3 dB margin are greater than 1140 km and 1700 km for the for EDFA and Raman systems, respectively.


Subject(s)
Amplifiers, Electronic , Optical Fibers , Spectrum Analysis, Raman/instrumentation , Telecommunications/instrumentation , Equipment Design , Equipment Failure Analysis , Microwaves
17.
Opt Express ; 20(9): 10353-8, 2012 Apr 23.
Article in English | MEDLINE | ID: mdl-22535124

ABSTRACT

Ultra-long-haul transmission at distances greater than 10,000 km is investigated for 112 Gb/s PM-QPSK signals using span lengths of 75 km and 100 km and all-Raman amplification. Two different ultra-low loss and large effective area optical fibers are studied. We demonstrate a reach length of 10,200 km for a 40 channel system using a fiber with effective area 112 µm(2) with 100 km spans, and a reach length of 13,288 km for a system with 75 km spans using a fiber with effective area of 134 µm(2).


Subject(s)
Amplifiers, Electronic , Optical Fibers , Surface Plasmon Resonance/instrumentation , Telecommunications/instrumentation , Equipment Design , Equipment Failure Analysis
18.
Opt Express ; 19(26): B363-9, 2011 Dec 12.
Article in English | MEDLINE | ID: mdl-22274044

ABSTRACT

We investigate transmission of 112 Gb/s PM-QPSK signals over 50 µm core diameter OM3 multimode fiber using the center launch approach. We demonstrate successful transmission of 16 DWDM channels over a distance of 635 km for a capacity-distance product of 1016 Tb/s-km. The limiting impairment appears due to mode coupling and multipath interference effects.

19.
Opt Express ; 19(26): B628-35, 2011 Dec 12.
Article in English | MEDLINE | ID: mdl-22274080

ABSTRACT

The implications of increasing the symbol rate for a given digital-to-analog converter (DAC) sampling rate are investigated by considering the generation of 112 Gbit/s PM 16-QAM signals (14 Gsym/s) using a 21 GSa/s DAC with 6-bit resolution.

20.
Opt Express ; 19(26): B96-101, 2011 Dec 12.
Article in English | MEDLINE | ID: mdl-22274126

ABSTRACT

We demonstrate transmission of 112 Gb/s PM-QPSK signals over a system with 200 km span lengths. Amplification is provided by hybrid backward-pumped Raman/EDFA amplifiers and reach lengths up to 6000 km for an 8 channel system and 5400 km for a 32 channel system are shown. As a means of maximizing OSNR, a simple hybrid fiber span configuration is used that combines two ultra-low loss fibers, one having very large effective area.

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