Advances in telecom and datacom optical components

We review and contrast key technologies developed to address the optical components market for communication applications. We first review the component requirements from a network perspective. We then look at different material systems, compare their properties, and describe the functions achieved to date in each of them. The material systems reviewed include silica fiber, silica on silicon, silicon on insulator, silicon oxynitride, sol-gels, polymers, thin-film dielectrics, lithium niobate, indium phosphide, gallium arsenide, magneto-optic materials, and birefringent crystals. We then describe the most commonly used classes of optical device technology and present their pros and cons as well as the functions achieved to date in each of them. The technologies reviewed include passive, actuation, and active technologies. The passive technologies described include fused fibers, dispersion-compensating fiber, beam steering, Bragg gratings, diffraction gratings, holographic elements, thin-film filters, photo...

Optical communication components

The development of a Fabry-Perot-type Ti,Er:LiNbO/sub 3/ waveguide laser of optimized CW output power up to 63 mW (/spl lambda//sub s/=1561 nm) at a pump power level of 210 mW (/spl lambda//sub p/=1480 nm) and a slope efficiency of up to 37% is reported. The theoretical model for the waveguide laser is presented and applied to determine the optimum resonator configuration using waveguide parameters obtained from a detailed characterization of the laser sample. With pulsed pumping, waveguide laser pulses of up to 6.2 W peak power were observed. Apart from residual relaxation oscillations, the laser emission proved to be shot-noise limited.

Ti:Er:LiNbO/sub 3/ waveguide laser of optimized efficiency

A reconfigurable WDM network, introduced as a new optical layer in present network hierarchy, has been demonstrated in the Stockholm Gigabit Network by the European RACE-MWTN consortium. New optical network elements, OXC and OADM, have been developed together with associated photonic technologies. The development also includes a management system that conforms to the standardized Telecommunication Management Network architecture.

Transport network involving a reconfigurable WDM network layer-a European demonstration

Multiple wavelength filtering/switching can be obtained using integrated acousto-optical wavelength filters and switches in LiNbO/sub 3/ by driving them with several RF signal simultaneously. As a consequence, interchannel interference occurs due to the interaction of several acoustic waves within the same mode converter resulting in an intensity modulation of the transmitted optical waves. System performance can be degraded as this interchannel interference leads to a power penalty equivalent to an additional cross talk. We present the coupled-mode analysis of the interchannel interference in the multiwavelength operation of acousto-optical filters and switches. Theoretical models are developed and confirmed by experimental results. Furthermore, the impact on WDM system performance is studied by measuring bit error rate characteristics and comparing the results with the theory. >

Interchannel interference in multiwavelength operation of integrated acousto-optical filters and switches

We report a polarization-independent integrated acousto-optical double-stage wavelength filter in X-cut, Y-propagating LiNbO/sub 3/. The device consists of a combination of four acousto-optical mode converters, a TE- and a TM-pass polarizer, and two polarization splitters; their specific design and properties are discussed. The filter has a bandwidth of 1.4 nm and a tuning range of 76 nm around /spl lambda/1.55 /spl mu/m. Maximum filter transmission is achieved with a RF drive power of only 80 mW; it excites via a single unidirectional transducer a guided surface acoustic wave driving the four polarization converters of both stages. Fiber-to-fiber insertion loss is 4.6 dB for TM- and 4.8 dB for TE-polarized waves. Multiwavelength filtering has been demonstrated. >

Polarization-independent integrated optical, acoustically tunable double-stage wavelength filter in LiNbO/sub 3/

Fully packaged, polarization independent, integrated acoustooptic 2/spl times/2 switches have been developed which can be also used as add/drop multiplexers. The devices have been fabricated in X-cut Y-propagating LiNbO/sub 3/ and can be operated at wavelengths around 1550 nm. They consist of passive polarization splitters and acoustooptic TE-TM converters with weighted coupling. A filter bandwidth of 2.0 nm and a tuning range of 130 nm have been obtained. The fiber-to-fiber insertion loss is <4.6 dB and a residual polarization dependence of 1.3 dB for bar-state and 0.1 dB for cross-state routing has been achieved.

S. Westenhofer

Papers

Polarization-independent integrated optical, acoustically tunable double-stage wavelength filter in LiNbO/sub 3/

Integrated optical, wavelength selective, acoustically tunable 2/spl times/2 switches (add-drop multiplexers) in LiNbO/sub 3/