Wavelength conversion for WDM communication systems using four-wavemixing in semiconductor optical amplifiers

Four-wave mixing (FWM) in semiconductor optical amplifiers is an attractive mechanism for wavelength conversion in wavelength-division multiplexed (WDM) systems since it provides modulation format and bit rate transparency over wide tuning ranges. A series of systems experiments evaluating several aspects of the performance of these devices at bit rates of 2.5 and 10 Gb/s are presented. Included are single-channel conversion over 18 nm of shift at 10 Gb/s, multichannel conversion, and cascaded conversions. In addition time resolved spectral analysis of wavelength conversion is presented

Pharmacologic labour analgesia and its relationship to postpartum psychiatric disorders: a scoping review.

PurposeThis scoping review aimed to summarize the current literature on postpartum psychiatric disorders (e.g., postpartum depression, postpartum anxiety, postpartum post-traumatic stress disorder) and the possible relationship of these disorders to the use of pharmacologic labour analgesia (e.g., epidural analgesia, nitrous oxide, parenteral opioids) to identify knowledge gaps that may aid in the planning of future research.SourcesPubMed, PsycINFO, CINAHL, and EMBASE were searched from inception to November 9, 2018 for studies that included both labour analgesia and the postpartum psychiatric disorders specified above.Principal findingsTwo reviewers assessed the studies and extracted the data. Of the 990 identified citations, 17 studies were included for analysis. Existing studies have small sample sizes and are observational cohorts in design. Patient psychiatric risk factors, method of delivery, and type of labour analgesia received were inconsistent among studies. Most studies relied on screening tests for diagnosing postpartum psychiatric illness and did not assess the impact of labour analgesia on postpartum psychiatric illness as the primary study objective.ConclusionsFuture studies should correlate screen-positive findings with clinical diagnosis; consider adjusting the timing of screening to include the antepartum period, early postpartum, and late postpartum periods; and consider the degree of labour pain relief and the specific pharmacologic labour analgesia used when evaluating postpartum psychiatric disorders

Wavelength conversion up to 18 nm at 10 Gb/s by four-wave mixing in a semiconductor optical amplifier

We characterize the conversion bandwidth of a four-wave mixing semiconductor optical amplifier wavelength converter. Conversion of 10-Gb/s signals with bit-error-rate (BER) performance of <10^-9 is demonstrated for wavelength down-shifts of up to 18 nm and upshifts of up to 10 nm

Cascaded wavelength conversion by four-wave mixing in a strained semiconductor optical amplifier at 10 Gb/s

We demonstrate for the first time cascaded wavelength conversion by four-wave mixing in a semiconductor optical amplifier. Bit-error-rate performance of <10^-9 at 10 Gb/s is achieved for two conversions of up to 9 nm down and up in wavelength. For two wavelength conversions of 5 nm down and up, a power penalty of 1.3 dB is measured. A system of two wavelength converters spanning 40 km of single-mode fiber is also demonstrated

Wireless Backhaul Node Placement for Small Cell Networks

Small cells have been proposed as a vehicle for wireless networks to keep up with surging demand. Small cells come with a significant challenge of providing backhaul to transport data to(from) a gateway node in the core network. Fiber based backhaul offers the high rates needed to meet this requirement, but is costly and time-consuming to deploy, when not readily available. Wireless backhaul is an attractive option for small cells as it provides a less expensive and easy-to-deploy alternative to fiber. However, there are multitude of bands and features (e.g. LOS/NLOS, spatial multiplexing etc.) associated with wireless backhaul that need to be used intelligently for small cells. Candidate bands include: sub-6 GHz band that is useful in non-line-of-sight (NLOS) scenarios, microwave band (6-42 GHz) that is useful in point-to-point line-of-sight (LOS) scenarios, and millimeter wave bands (e.g. 60, 70 and 80 GHz) that are recently being commercially used in LOS scenarios. In many deployment topologies, it is advantageous to use aggregator nodes, located at the roof tops of tall buildings near small cells. These nodes can provide high data rate to multiple small cells in NLOS paths, sustain the same data rate to gateway nodes using LOS paths and take advantage of all available bands. This work performs the joint cost optimal aggregator node placement, power allocation, channel scheduling and routing to optimize the wireless backhaul network. We formulate mixed integer nonlinear programs (MINLP) to capture the different interference and multiplexing patterns at sub-6 GHz and microwave band. We solve the MINLP through linear relaxation and branch-and-bound algorithm and apply our algorithm in an example wireless backhaul network of downtown Manhattan.Comment: Invited paper at Conference on Information Science & Systems (CISS) 201

Wavelength conversion by four-wave mixing in semiconductor optical amplifiers

Time-resolved spectral analysis is performed on 10 Gb/s signals wavelength converted by four-wave mixing (FWM) in semiconductor optical amplifiers. A pattern-dependent chirp resulting from parasitic gain modulation by the signal is measured and characterized as a function of the converter's pump-to-probe ratio. This chirp is found to be insignificant for pump-to-probe ratios exceeding 9 dB

Time-resolved Spectral Analysis Of Phase Conjugation By Four-wave Mixing In Semiconductor Optical Amplifiers

Optical phase conjugation provides a mechanism for achieving dispersion compensation in optical fibers. This has been demonstrated by four-wave mixing (FWM) in both fiber and semiconductor optical amplifiers (SOAs). Imperfect phase conjugation will prevent exact reconstruction of a dispersed data stream. Here we use time-resolved spectral analysis (TRSA) to evaluate the performance of FWM in SOAs for phase conjugation