An optical component is disclosed. The optical component includes a tap waveguide and a primary waveguide positioned on a base. The tap waveguide is configured to receive a portion of a light signal traveling along the primary waveguide. The portion of the light signal received by the tap waveguide is the tapped portion of the light signal. A direction changing region is configured to receive the tapped portion of the light signal from the tap waveguide and to direct the tapped portion of the light signal travels away from the base. A light sensor is configured to receive the tapped portion of the light signal from the direction changing region.

Waveguide tap monitor

This paper presents an analysis of a silicon-on-insulator (SOI) waveguide structure to be used for phase modulation at 1.3 /spl mu/m. The device consists of a two-dimensional (2-D) strip waveguide and a p/sup +//N/sup -//N/sup +/ lateral diode to realize the effective index modulation by free-carrier injection. We have calculated that an effective index modulation between 5/spl middot/10/sup -4/ and 10/sup -3/ could be obtained with current densities in the range from 500 to 1600 A/cm/sup 2/. A detailed numerical simulation of the device transient response is also reported. We demonstrate that an effective index modulation of 5/spl middot/10/sup -4/ could be obtained with a cutoff frequency of about 100 MHz. The phase modulator has a predicted figure-of-merit (FoM) of 160/spl deg//V/mm and a chirp factor of 25. Due to its full compatibility with complementary metal-oxide-semiconductor (CMOS)-SOI technology, the device is interesting for low-cost silicon-based optoelectronic systems.

Numerical simulation of a silicon-on-insulator waveguide structure for phase modulation at 1.3 /spl mu/m

A rigorous numerical procedure is presented for the accurate characterization of optical filters incorporating two nonidentical coupled waveguides. Numerically simulated results are shown for InGaAsP/InP-based design indicating narrow bandwidth is achievable, by using waveguides with two-dimensional confinement. The numerical solution presented here also suggests that by using the multiple quantum well (MQW) region for a waveguide core the polarization dependent properties of the device can be compensated.

Accurate characterization of optical filters with two-dimensional confinement

A data processing apparatus for data processing an audio signal includes an input terminal (1) for receiving the audio signal, a 1-bit A/D converter (4) for A/D converting the audio signal to for a bitstream signal, a prediction unit (10) for carrying out a prediction step on the bitstream signal to form a predicted bitstream signal, a signal combination unit (42) for combining the bitstream signal and the predicted bitstream signal to form a residue bitstream signal, and an output terminal (14) for supplying the residual bitstream signal.

Bitstream data reduction coding by applying prediction

An optical filter system is disclosed. The optical filter system includes a first filter configured to output light signals having wavelengths falling within a plurality of periodically spaced wavelength bands. A second filter in optical communication with the first filter and being configured to output light signals having wavelengths falling within a plurality of periodically spaced bands. The period of the bands associated with the first filter is different than the period of the bands associated with the second filter.

Tunable optical filter

The spectral index method is applied to closely coupled rib waveguides. Analytical expressions in terms of the propagation constant β are given for symmetric and antisymmetric polarised modes. The calculated coupling lengths are in excellent agreement with those obtained by mainframe programs.

Spectral index method applied to coupled rib waveguides

It is shown that the design of ridge waveguide couplers with a uniformly layered refractive index profile can be extended to include the nonuniformity arising within an active layer as a result of carrier injection. This is analysed using the spectral index method combined with a degenerate perturbation approach. The simplicity of this approach makes it possible to solve design problems in which the correct mixing of the fields beneath the ridges is an essential feature of the modelling, and necessary for accuracy of design.

Design of ridge waveguide couplers with carrier injection using discrete spectral index method

A wavelength filter consisting of two dissimilar rib waveguides is analysed with respect to the waveguide response and tuning. An optimised structure with a 0.41 nm bandwidth and a 9 mm coupling length is designed. Two techniques are developed to model tapered filters, where the guide separation is varied to improve the wave-length response. A good agreement is found between both methods.

http://ieeexplore.ieee.org/iel1/2216/3504/00124254.pdf

Analysis of rib waveguide coupler filters

The discrete spectral index (DSI) method has proved successful for modelling single rib waveguides, symmetric and asymmetric couplers [1]. For couplers, the method produces propagation constants for the lowest-order symmetric and antisymmetric supermodes, βs and βas, and generates accurate field profiles.

S.V. Burke

Papers

Spectral index method applied to coupled rib waveguides

Design of ridge waveguide couplers with carrier injection using discrete spectral index method

Analysis of rib waveguide coupler filters

Application of the Discrete Spectral Index Method to the Design of Coupled Ridge Waveguides with Carrier Injection