Seppo Honkanen

Double-ion-exchange process in glass for the fabrication of computer-generated waveguide holograms.

We experimentally optimize double-ion-exchange process parameters to achieve a designed phase modulation for a wave front passing through a computer-generated waveguide hologram and numerically analyze the effects of fabrication errors. We also demonstrate a gradient-thickness waveguide hologram for ? beam splitting.

Buried-glass waveguides by ion exchange through ionic barrier

Fabrication of buried single-mode glass waveguides by ion exchange through the ionic barrier is studied. In this process, an unmasked potassium ion exchange is first performed to form an ionic barrier. The purpose here is to reduce sodium concentration near the surface (not to make a waveguide). The waveguides are formed in the second step of the process by masked silver ion exchange through this leaky ionic barrier. The calculated waveguide index profiles and both calculated and measured mode profiles are presented.

Experimental optimization of double-ion exchange in glass for computer-generated waveguide holograms

We optimize experimentally the double ion-exchange process parameters to achieve a designed phase modulation for a wavefront passing through a computer-generated waveguide hologram. We also demonstrate a gradient-thickness waveguide hologram (kinoform) for 1/8 beam splitting.

Glass integrated optics circuit for 1.3/1.55 micrometer optical communication system

We propose the integration, in a single glass substrate, of a 0.807/1.3 micrometers wavelength multiplexer, a 1.48/1.55 micrometers wavelength multiplexer, and a 1.30/1.55 micrometers wavelength multiplexer followed by a 1/8 splitter by potassium and silver double-ion exchange. The wavelength multiplexers are based on nonsymmetric three-port Mach-Zehnder interferometers, and symmetrical Y-junctions are used for achromatic splitting. The facet-to-facet excess loss in the 0.807/1.3 micrometers and 1.48/1.55 micrometers multiplexers is less than 3 dB and in the integrated 1.30/1.55 micrometers multiplexer and 1/8 splitter less than 2.65 dB. The device can be used, in connection with an Er-doped fiber, in future wavelength division multiplexing subscriber networks, in which amplification is needed at 1.3 micrometers and 1.55 micrometers wavelength regions.

Rare-earth (Nd3+, Er3+, and Yb3+)-doped aluminium phosphate sol-gel films

In this paper, we report on fabrication process of ordinary and rare-earth-doped aluminum phosphate sol-gel films and their physical and optical properties. The gel films are transparent, hard and of good optical quality as glass. High doping of rare-earths (Nd3+, Er3+ and Yb3+) are realized in films with this technique. This type of doped films offer potential benefits for applications in the field of active integrated optics devices for optical telecommunication systems.

Integrated optical ring resonator with a novel nonsymmetric Mach-Zehnder interferometer as input/output coupler

An integrated optical ring resonator employing a novel four-port nonsymmetric Mach-Zehnder interferometer as an input/output coupler is proposed and demonstrated. The interferometer based on two hybrid optical couplers is essentially a 0.98 micrometers /1.55 micrometers wavelength multiplexer in connection with the ring resonator. The device is designed by using the effective indices of the guided modes in a silver ion-exchanged waveguide and is fabricated in glass substrate by double-ion-exchange process. The input/output coupler for the ring resonator is characterized using a continuous light source as well as lasers at (lambda) equals 1.06 micrometers , (lambda) equals 1.3 micrometers and (lambda) equals 1.523 micrometers . The finesses of 5 for the ring resonant is measured at (lambda) equals 1.523 micrometers . It is employed to estimate the propagation losses in the ring waveguide as 0.17 dB/cm. Potential applications of the device are discussed.

Glass waveguides by ion exchange with ionic masking

The fabrication of single-mode glass waveguides by silver ion exchange with ionic masking has been studied. In this ionic masking process metallic stripes are first patterned to mask the potassium ion exchange. Then the stripes are removed and silver ion exchange is performed. This produces waveguides in the previously masked regions where potassium ions are not present. The study on the efficiency of the ionic mask is presented. Then the measured mode profiles are compared to the calculated mode profiles. Finally, the situation in which potassium ion exchange does not increase the refractive index of the glass is discussed.

Effect of thermal post-annealing on spectral transmission of 0.807/1.3 μm, 1.48/1.55 μm, and 1.3/1.55 μm ion-exchanged Mach-Zehnder interferometer wavelength demultiplexers/multiplexers

Nonsymmetric three-port integrated optical Mach-Zehnder interferometer configuration is employed to make 0.807/1.3 micrometers , 1.3/1.55 micrometers , and 1.48/1.55 micrometers wavelength multiplexers/demultiplexers. The devices are produced by potassium-silver double-ion exchange process. The effect of thermal post-annealing on spectral behavior of the fabricated devices is investigated. The losses and extinction ratios of the fabricated devices are also determined.

Polymer-glass-waveguide all-optical switches

Two polymer-glass-waveguide all-optical switches are proposed. One consists of an X-branch channel glass waveguide with a strip of nonlinear polymer on the center top of two-mode region (double width). It is based upon the power-dependent two-mode interference principle. Another is composed of an asymmetric Y-branch glass waveguide with a strip of nonlinear polymer on top of one branch. It is an adiabatic type all-optical switch. Theoretical analyses show that, by properly choosing device structure parameters, low crosstalk or even complete switchings are possible with low optical power.

Nonsymmetrical two- and three-port Mach-Zehnder interferometers in glass by ion exchange

Nonsymmetrical integrated optical Mach-Zehnder interferometers are produced in glass by potassium ion exchange and by silver ion exchange with ionic masking. Two- and three-port nonsymmetrical Mach-Zehnder interferometer structures with path length difference ranging from 10.75 micrometers to 259.7 micrometers are studied.