Glass ion-exchange technology for wavelength management applications

Abstract

We report the achievement of buried single-mode waveguides in special Boro-Aluminum-Silicate glass. The waveguides are characterized by very low propagation loss (< 0.1dB/cm) and negligible birefringence. The optical mode at the input and output ports is essentially identical to the mode of a standard single-mode optical fiber. We fabricated and tested several devices and report here 1x8 and 1x16 powers splitters and an interleaver defined for a 100GHz DWDM network.Due to the low birefringence of the waveguides, the TE and TM responses of the device are undistinguishable by customary characterization equipment. In addition we report a technique for permanent trimming of the optical circuit by localized heating. This unique advantage of ion-exchange technology, allowed us the adjustment of devices' parameters at post-fabrication stage. As an example, the trimming of a 2x2 directional coupler manifested here in the control of coupling coefficient value over a wide range (0.04-1 .5). The process control was such that a target value of 0.5 for the coefficient was accurately attained. The same process enabled us the tuning of the interleaver to the ITU grid within 1 Opm accuracy.

Producing the Gradient Changes in Glass Refraction by the Ion Exchange Method — Selected Aspects

“…The x coordinate is calculated here into the glass (on the surface x = 0) to the direction perpendicular to its surface. This profile can also be described theoretically using the normalized concentration u(x) of admixture ions introduced into the glass -see equation (5). Figure 10.…”

“…In the first case the refractive index gradient has only one coordinate, while in the waveguides of channel type it has two. On the basis of such structures various elements of planar waveguide optics can be constructed, such as: splitters of Y type [1], splitters of 1xN type [2], multiplexers [3][4][5][6][7], directional couplers [8], ring resonators [9][10], planar polarizers [11], planar interferometers [12][13] or gradient MMI structures [14][15][16]. These elements can cooperate with the fiber waveguides.…”

Ion-exchanged glass waveguide technology: a review

“…114,115 In arrayed-waveguide grating (AWG) multiplexers, ion-exchanged waveguides provide low polarization sensitivity 112 and thermal fine-tuning of the device response is possible. 116 The thermo-optic effect can be utilized in variable attenuator devices; an ion-exchanged Mach-Zehnder structure variable attenuator was demonstrated with 1 dB insertion loss, dynamic range of 38 dB, and polarization dependent loss varying from 0.2 to 0.6 dB in the attenuation range of 10 to 20 dB. 117 The maximum power consumption of the device was 138 mW.…”

“…The performance of these devices is excellent, so their prospects depend largely on emerging market needs, and competitiveness of alternate solutions, based on other waveguide technologies, or microoptical or fiber components. Other passive guided-wave devices and circuits-for example those targeting WDM applications 116 -could be based on similar fabrication processes. A key question here is whether such components can achieve sufficient performance and reliability at competitive fabrication cost.…”

Producibility of the ion-exchange method in manufacturing gradient refractive index in glass

“…1b). On the basis of such structures various elements of waveguide planar optics may be designed, such as splitters of Y type [36], 1xN splitters [37], multiplexers [38][39][40][41][42], directional couplers [43], ring resonators [44,45], planar polarizers [46], planar interferometers [47,48], gradient structures of multimode interference couplers MMI [49][50][51]. These elements cooperate with fiber waveguides.…”