PHASAR Demultiplexer Research Articles

Low-loss, compact, and polarization independent PHASAR demultiplexer fabricated by using a double-etch process

A compact low-loss polarization independent 8 /spl times/ 8 PHASAR demultiplexer is presented. Device size is 0.93 /spl times/ 0.75 mm/sup 2/. On-chip losses are less than 4 dB and crosstalk is better than -20 dB. The device is suitable for integration with electro-optical switches for application in integrated optical crossconnects, add-drop multiplexers and multiwavelength lasers.

A low-loss 16-channel polarization dispersion-compensated PHASAR demultiplexer

An improved technology for realizing high-quality PHASARs is reported, which is compatible with the integration of electrooptical switches for use in add-drop multiplexers. This technology is demonstrated in a 16-channel polarization independent low loss (<2.4 dB on-chip) PHASAR.

First InP-based reconfigurable integrated add-drop multiplexer

A four-channel reconfigurable integrated add-drop multiplexer on InP-substrate is reported. The device consists of a 5/spl times/5 PHASAR demultiplexer integrated with Mach-Zehnder interferometer electrooptical switches. Total device size is 3/spl times/6 mm/sup 2/. All routing configurations of four wavelengths have been demonstrated. Crosstalk values are better than -20 dB. On-chip loss for the dropped or added signals and for the signals coupled from the input to the output port are lower than 7 and 11 dB, respectively.

Strained [formula omitted] MQW layers grown by CBE for optical components

We investigated the influence of strain on the optical birefringence in waveguides consisting of Ga x In 1 − x As InP multiquantum well layers. The range of growth parameters to achieve good quality material for the waveguide structures were determined. In a number of layer structures low-loss optical waveguides and PHASAR demultiplexers were fabricated and characterized. The polarization dependence of the demultiplexer can be reduced by using quantum wells strained in tension. Without any precaution, the tensile strain in the well is limited by relaxation at ϵ w ≈ −0.8%. The strain in the well can be further increased to ϵ w ≈ −1% by introducing a strain-balancing layer of a compressive strained InAs monolayer in the InP barrier. But polarization independence is not yet achieved. The results indicate, that there is no negative effect of the strain-balancing layer on the optical performance. Also a number of design criteria for polarization independent waveguides are determined.