Glenn Baxter

Highly programmable wavelength selective switch based on liquid crystal on silicon switching elements

We present a novel wavelength selective switch (WSS) based on a liquid crystal on silicon (LCOS) switching element. The unit operates simultaneously at both 50 and 100 GHz channel spacing and is compatible with 40 G transmission requirements.

Dispersion Trimming in a Reconfigurable Wavelength Selective Switch

We experimentally demonstrate dispersion compensation in a wavelength selective switch, and characterize the bandwidth-dispersion product. At a channel bit-rate of 80 Gbit/s, we compensate for various amounts of dispersion (up to ±60 ps/nm), tunable for each wavelength division multiplexed channel, solely by adjusting the phase front of the optical signal inside the wavelength selective switch. Error-free operation is obtained for all of the channels, and for each output port after propagation over various lengths of dispersive fiber.

Spectral modeling of channel band shapes in wavelength selective switches

A model for characterizing the spectral response of the passband of Wavelength Selective Switches (WSS) is presented. We demonstrate that, in contrast to the commonly used supergaussian model, the presented model offers a more complete match to measured results, as it is based on the physical operation of the optical system. We also demonstrate that this model is better suited for calculation of WSS channel bandwidths, as well as predicting the final bandwidth of cascaded WSS modules. Finally, we show the utility of this model in predicting channel shapes in flexible bandwidth WSS channel plans.

1x11 few-mode fiber wavelength selective switch using photonic lanterns

We demonstrate an 11 port count wavelength selective switch supporting spatial superchannels of three spatial modes, based on the combination of photonic lanterns and a high-port count single-mode WSS.

Dual-polarization frequency-modulated laser source

Diode-pumped 1.3-/spl mu/m as well as 1.06-/spl mu/m Nd:YAG lasers have been operated with two orthogonally polarized modes at slightly different frequencies. The frequency difference, controlled by an intracavity electrooptic crystal, may be modulated. Thus, two polarized-outputs are obtained; one at a constant frequency, and the other frequency-modulated. This is a novel source for frequency-modulated heterodyne detection systems where the reference (local oscillator) frequency originates from the signal laser itself and is automatically locked to it.

Locking the cavity of a pulsed periodically poled lithium niobate optical parametric oscillator to the wavelength of a continuous-wave injection seeder by an “intensity-dip” method

Injection seeding by a single-mode continuous-wave (cw) laser provides a convenient way to achieve narrowband tunable operation of a laser with a broad spectral gain profile, or of an optical parametric oscillator (OPO). Continuous single-mode tunability of the laser or OPO output usually requires the length of the optical cavity to be controlled as the injection-seeding wavelength is scanned. We report a novel variant on established methods of locking the optical cavity length to the seed wavelength. Our approach takes advantage of the resonance properties of an optical cavity. When the cavity is in resonance with the cw seed radiation, the total intensity of that radiation reflected off the cavity displays a pronounced dip; this intensity dip can be used as a locking signal to reset the cavity length piezoelectrically during each interval between the pump pulses that excite the laser or OPO. Our active cavity-locking scheme is realized in the case of a ring-cavity OPO, incorporating periodically poled l...

Wavelength-Selective Reconfiguration in Transparent Agile Optical Networks

The development of wavelength-selective switching (WSS) technologies is enabling the next generation of transparent optical networks, with remote reconfiguration of the mesh network providing optimal network utilization. Whereas first generations of networks were based on the ITU-defined fixed 50/100-GHz grids, true spectral transparency becomes possible with the introduction of Flexible Grid (FG) wavelength switching within the mesh network. Optical architectures that support the addition and dropping at any node of bandwidth-variable channels will allow optimal spectral utilization in transmission of legacy and next-generation transmission formats.

OPO CARS: coherent anti-Stokes Raman spectroscopy using tunable optical parametric oscillators injection-seeded by external-cavity diode lasers

Abstract Coherent anti-Stokes Raman spectroscopy (CARS) is performed on nitrogen gas using the signal wave from a pulsed β-barium borate optical parametric oscillator (OPO), which has a passive ring cavity and is injection-seeded at its idler wavelength by a single-mode, external-cavity diode laser. The observed CARS linewidths are consistent with an optical bandwidth of 0.01 cm −1 for the continuously tunable OPO signal radiation. Moreover, injection seeding with two diode lasers generates two-line rovibrational CARS spectra giving thermometric information on a single-shot basis. The utility of these OPO CARS methods for combustion diagnostics is indicated.

High performance `Drop and Continue' functionality in a Wavelength Selective Switch

We demonstrate for the first time channel-selective optical power sharing between a designated express-port and any drop-port of a 1×9 50 Channel WSS. Bit-Error Rate testing shows that this drop- and-continue functionality can be implemented with negligible system penalty.

Flexible and Reconfigurable Time-Domain Demultiplexing of Optical Signals at 160 Gb/s

We present experimental results showing reconfigurable switching of four 40-Gb/s tributary channels in a 160-Gb/s data signal using Fourier-domain temporal pulse shaping and all-optical processing. Arbitrary combinations of multiple tributary channels are switched out of a high-speed data-modulated signal. The performance is characterized using a fast optical sampling oscilloscope and bit-error-rate measurements.