Abstract: Optical apparatus with improved center wavelength temperature stability. In an embodiment, an AWG has a plurality of slots inserted along the optical paths. The slots contain one or more compensation materials which collectively correct for an order Q temperature dependency of the AWG base material. Q>=2 or the number of compensation materials is at least 2 or both.

Abstract: An optical branching component particularly suitable for use as a tap device is described. The component has two optical waveguides coupled between two optical couplers which each include at least one MMI supporting at least two guided modes. There is an effective optical path length difference between the two waveguides and the coupling strength of at least one of the couplers monotonically decreases with increasing wavelength in the operational wavelength region of the component. This means a coupler with relatively large coupling strength and relatively low polarization dependency can be used in the component, giving low polarization dependent variation in the tap ratio, particularly for small tap ratios. Moreover, the use of MMIs in the couplers avoids the need to fabricate to a high process tolerance very small gaps between two waveguides, as can be the case with directional couplers used in prior art branching component designs.

Abstract: Optical apparatus with improved center wavelength temperature stability. In an embodiment, an AWG has a plurality of slots inserted along the optical paths. The slots contain one or more compensation materials which collectively correct for an order Q temperature dependency of the AWG base material. Q>=2 or the number of compensation materials is at least 2 or both.

Abstract: Optical apparatus with improved center wavelength temperature stability. In an embodiment, an AWG has a plurality of slots inserted along the optical paths. The slots contain one or more compensation materials which collectively correct for an order Q temperature dependency of the AWG base material. Q>=2 or the number of compensation materials is at least 2 or both.

Abstract: In an arrayed waveguide grating (AWG) comprising fist and second slab waveguides and an array of waveguides optically coupled therebetween, the angle of the array waveguides at the slab waveguides is chirped according to the following equation: &thgr;i=ArcSine (i.&Dgr;&thgr;), where i=−(N−1)/2, −(N−1)/2+1, . . . , +(N−1)/2 where i is the array waveguide number, N is the number of array waveguides, and &Dgr;&thgr; is a constant. The chirping removes third-order aberration (COMA) which would otherwise cause asymmetry in the AWG output channel signals, especially where the AWG has a flattened passband.

Abstract: In an arrayed waveguide grating (AWG) comprising fist and second slab waveguides and an array of waveguides optically coupled therebetween, the angle of the array waveguides at the slab waveguides is chirped according to the following equation:

Abstract: A passband-flattened phasar including two free space regions coupled by a plurality of waveguides having predetermined differences between their lengths so as to act as an arrayed waveguide grating. The phasar is particularly useful in a wavelength-division multiplexed (WDM) optical communication system transmitting multiple wavelength systems arranged in a wavelength comb with a constant wavelength channel spacing. The input waveguide is coupled to the first free space region through a Mach-Zehnder interferometer (MZI) having two waveguide arms of differing lengths receiving approximately equal amounts of the input signal. The arms differ in lengths so as to produce a phase difference between them. In a WDM network, the waveguide arm produce a phase difference such that the free spectral range of the MZI equals the wavelength channel spacing, such that the wavelength response of the MZI is the same for each of the WDM wavelengths.