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We investigate the mitigation of distortion due to self-phase modulation and dispersion in 40-Gb/s nonreturn-to-zero wavelength-division-multiplexed transmission using a multichannel optical equalizer. The ability of the equalizer to reduce the signal degradation due to fiber nonlinearities was demonstrated. We achieved 21-channel transmission at BER <10-9 without forward error correction over 750 km of true wave reduced slope fiber with 107-km amplifier span lengths. [ABSTRACT FROM PUBLISHER]

We describe a method to study dense wavelength-division multiplexed (DWDM) transmission over amplified links that have no inline dispersion compensation and where the channels have nearly 100% precompensation. The approach is based on two recirculating loops that are linked to each other. Using this apparatus, we demonstrate DWDM transmission of 16 nonreturn-to-zero 10-Gb/s channels on a 50-GHz grid over links ranging from 320 to 1280 km of standard single-mode fiber with precompensation values ranging from -5440 to -21 760 ps/nm. [ABSTRACT FROM PUBLISHER]

We present a planar lightwave circuit curved 2×2 coupler. Its splitting ratio has a low sensitivity to wavelength, polarization, and fabrication yet is low-loss and compact. We present simple formulae for its design. We demonstrate a 50/50 version in silica-on-silicon waveguides. We discuss the tradeoff between amplitude accuracy and phase accuracy in such densensitized couplers. [ABSTRACT FROM PUBLISHER]

Optical duobinary transmission at 42.7 Gb/s is demonstrated using a commercially available 10-Gb/s LiNbO3 modulator. The intrinsic response of the 10-Gb/s electrooptic Mach-Zehnder modulator (MZM) is used to create a low-pass-filtered (LPF) duobinary signal, which shows a minimum optical signal-to-noise ratio (OSNR) requirement penalty of ∼4 to ∼6 dB as compared to nonreturn-to-zero (NRZ) signals. However, when the MZM-LPF duobinary is filtered with a 50-GHz 3-dB bandwidth first-order Gaussian filter, a significant improvement in required OSNR is seen. In contrast, similar optical filtering of NRZ data creates a significant OSNR penalty such that the NRZ and MZM-LPF duobinary data have nearly identical OSNR requirements. Therefore, the MZM-LPF duobinary technique may be a cost-effective approach to high-spectral-efficiency transmission at 42.7 Gb/s. [ABSTRACT FROM PUBLISHER]

We previously demonstrated a colorless three-stage Mach-Zehnder-interferometer-type 10-Gb/s tunable dispersion compensator (TDC) in a silica-on-silicon planar lightwave circuit. However, the bandwidth was too narrow to tolerate typical transmitter wavelength drift. Here we demonstrate a wider bandwidth version, in which we increased the TDC free-spectral range (FSR) and put two TDCs in series onto the same chip. Key features are that a single voltage tunes the entire device, and a single half-wave plate makes the entire device polarization insensitive. This 50-GHz FSR device allows 180 km of 9.95-Gb/s transmission. We also demonstrate a 100-GHz FSR version, which compensates ∼±200 ps/nm of 42.7-Gb/s transmission. [ABSTRACT FROM PUBLISHER]

Novel five-band 8-skip-0 band filters realized in silica waveguide planar lightwave circuit technology were successfully used to demonstrate versatile wavelength-division-multiplexed (WDM) optical networking. Forty C-band channels spaced 100 GHz apart grouped in five bands of eight channels each allowed WDM networking without loss of any channel within the available optical bandwidth. We demonstrate simultaneous transport of 10 and 40 Gb/s with rate-appropriate optical add-drop nodes. [ABSTRACT FROM PUBLISHER]

An analytical expression for the signal distortion that results from the loss ripple (LR) in the passband of an optical component is derived. The expression, when simplified to its first-order form, provides a clear physical picture of how the signal is affected by the ripple period, magnitude, and the signal center frequency location with respect to the LR. We also derive the optical signal-to-noise ratio penalty resulting from the LR in both on-off keyed and differential phase-shift keyed (DPSK) transmissions. Furthermore, a special kind of LR can be applied to mitigate the penalty associated with tight optical filtering, which is experimentally verified with a 42.7-Gb/s DPSK signal passing through two filters having a 3-dB bandwidth of 43 GHz and an LR generator. [ABSTRACT FROM PUBLISHER]

We previously reported a simple 10-Gb/s Mach-Zehnder-interferometer-type tunable dispersion compensator that requires only one control voltage. However, we used an expensive polarization-diversity scheme to achieve polarization independence. Here, we take advantage of the device symmetry and use a single half-wave plate to achieve low polarization sensitivity, saving significant cost and size. We demonstrate 200-km transmission of 10-Gb/s chirped nonreturn-to-zero data with only 1.8-dB path penalty. [ABSTRACT FROM PUBLISHER]

We demonstrate significant improvement in the measured bit-error rates of 40-Gb/s signals distorted after passing through a saturated semiconductor optical amplifier (SOA) by using a simple colorless general optical equalizer. The optical equalizer reduces the overshoots arising from the nonlinear gain dynamics of the SOA and improves the opening of the eye. We study the improvement in receiver sensitivity by using the equalizer while varying the optical power and wavelength at the input of the SOA. [ABSTRACT FROM PUBLISHER]

We report a hierarchical optical add-drop multiplexer (OADM) network that supports 10-, 40-, and 160-Gb/s data rates with the same bandwidth efficiency. The data rates can be upgraded without hardware modification in the OADM. This hierarchical OADM network is equipped with high capacity (1.6 Tb/s) for traffic growth, while providing different granularities for diverse bandwidth requirements as fine as 12.5 GHz in optical domain. We investigate the transmission penalty through the waveband OADMs, and compare the performance between all-through traffic and add-drop traffic of neighboring wavebands at 40-Gb/s rate. [ABSTRACT FROM PUBLISHER]

A 16-channel 100-GHz-spacing wavelength selective cross connect is demonstrated using a combination of planar waveguides and MEMS piston-mirrors. Interswitch crosstalk is eliminated and switching speed is an order of magnitude faster than typical thermooptic switches. The power consumption is smaller than one microwatt per switch. An extinction ratio of 20 dB and an insertion loss of 10.6 dB are demonstrated. [ABSTRACT FROM PUBLISHER]

A novel technique for monitoring the alignment status between the pulse carver and data modulator for return-to-zero differential phase-shift keying systems is proposed and demonstrated. The proposed technique utilizes a polarization-maintaining fiber, polarizer, and power meter. Both the simulation and measurement results show that the proposed technique can monitor the bit-error-rate degradation caused by timing misalignment between the pulse carver and data modulator. [ABSTRACT FROM PUBLISHER]

We demonstrate that a simple general optical equalizer permits the generation of 42.7-Gb/s nonreturn-to-zero data from an 8-GHz bandwidth LiNbO3 modulator. The sensitivity at 10-9 bit-error ratio is only 1 dB poorer than using a 36-GHz bandwith modulator. Since the equalizer can act on many channels simultaneously and be used in a set-and-forget mode, we can potentially reduce the cost of 40-Gb/s transmitters. [ABSTRACT FROM PUBLISHER]

We demonstrate six-channel 160-Gb/s wavelength-division-multiplexed transmission over 20 100-km spans of nonzero-dispersion fiber, with a spectral efficiency of 0.53 b/s/Hz. We achieve this result using optical-time-division multiplexing with polarization bit interleaving and return-to-zero differential-phase-shift-keying modulation format. We also operate at 170.6 Gb/s per channel to emulate the use of forward error correction. [ABSTRACT FROM PUBLISHER]

We present a widely tunable laser consisting of a semiconductor optical amplifier (SOA) glued directly to a silica waveguide grating router, that can be packaged without submicrometer alignments, air gaps, or SOA vertical spot-size conversion. However, issues regarding thermooptic power consumption and modal stability remain to be solved. [ABSTRACT FROM PUBLISHER]

We demonstrate a colorless thermooptic-lens-based tunable dispersion compensator integrated with a tunable optical noise filter. The free-spectral range is 200 GHz, the tuning range is ±200 ps/nm, the transmissivity 3-dB bandwidth is >40 GHz, and the linear group delay bandwidth is >48 GHz. [ABSTRACT FROM PUBLISHER]

We present a novel band demultiplexer design for planar lightwave circuits. It consists of two perfectly sampled waveguide grating routers connected by sets of equal-path-length waveguides separated on one side. Its advantages are compactness, sharp passband corners, and a lack of chromatic dispersion. [ABSTRACT FROM PUBLISHER]

A fully packaged 40-channel 100-GHz-spacing full-coupler-type synchronized-gratings multiplexer with a 1-dB bandwidth >57 GHz, total adjacent crosstalk ±35 GHz around the ITU grid <-18 dB, and loss <3.5 dB for all channels is presented. [ABSTRACT FROM PUBLISHER]

We present a new design for a digitally tunable laser using two waveguide grating routers with different free spectral range. For an N-channel device, both the number of required amplifiers and the number of required grating arms scale as the square root of N, resulting in a more compact device than previously demonstrated and better scaleability. Contrary to previously demonstrated devices with a reduced number of amplifiers, all wavelength channels are multiplexed together in one common channel, allowing for a higher output power. Tuning speeds below 10 ns are envisioned. Experimental results are presented. [ABSTRACT FROM PUBLISHER]

The authors demonstrate an integrated add-drop filter with true reconfigurability. It can drop any combination of eight wavelengths to any of eight drop ports, with less than 7 dB loss. Its features are suitable for mass production: use of standard silica waveguide technology, double-rejection switching and filtering for all paths, compactness, and power-efficient thermooptic switching. [ABSTRACT FROM PUBLISHER]