Dominik G. Rabus

Photonic integrated circuits by DUV-induced modification of polymers

The results achieved with polymer Y-splitters, codirectional couplers, and multimode interference couplers, realized by deep ultraviolet lithography are presented. The devices are designed and fabricated for the 1.55-/spl mu/m wavelength region and have a waveguide loss of 1 dB/cm. The waveguide width is 7.5 /spl mu/m. The fiber-chip coupling loss is 0.5 dB per facet. The polarization-dependent loss is <0.15 dB.

A GaInAsP-InP double-ring resonator coupled laser

A monolithic single-mode GaInAsP-InP double microring resonator coupled laser is demonstrated for the first time. The laser comprises two passive ring resonators, semiconductor optical amplifiers in the bus waveguides, and 3-dB codirectional couplers. The laser has an output power of 0.5 mW with a sidemode supression ratio of >35 dB. The tunability is demonstrated using integrated platinum resistors on top of the waveguides in the rings.

Fabrication of photonic integrated circuits by DUV-induced modification of polymers

The results achieved with polymer Y-splitters, codirectional couplers, and multimode interference couplers, realized by deep ultraviolet lithography are presented. The devices are designed and fabricated for the 1.55-/spl mu/m wavelength region and have a waveguide loss of 1 dB/cm. The waveguide width is 7.5 /spl mu/m. The fiber-chip coupling loss is 0.5 dB per facet. The polarization-dependent loss is <0.15 dB.

Ring Resonator Lasers using Passive Waveguides and Integrated Semiconductor Optical Amplifiers

We present a review of our work on ring lasers using passive waveguides and couplers (directional and multimode interference) integrated with semiconductor optical amplifiers (SOAs). Two architectures are given in this paper. The first architecture includes the SOA inside the ring cavity. The second architecture also known as ring resonator coupled laser, consists of passive ring resonators having SOAs in the bus waveguides. The increased photon lifetime in the cavity and the tunability of the ring response can be used to make compact, narrow linewidth, and widely tunable lasers. Four-wave mixing applications are also addressed.

A Bio–Fluidic–Photonic Platform Based on Deep UV Modification of Polymers

We present a review of our work on deep UV (DUV) modification of methacrylate-based polymers. This technology serves as a platform for realizing planar and ridge waveguide-based devices, fluidic channels, and enables the patterning of living cells including neural cells in vitro. Details on the DUV chemistry and fabrication technologies including hot embossing of multimode interference couplers will be given

Coupling of Organic Semiconductor Amplified Spontaneous Emission Into Polymeric Single-Mode Waveguides Patterned by Deep-UV Irradiation

Single-mode waveguides were fabricated by deep ultraviolet radiation in poly(methyl methacrylate) (PMMA). Using a masking process, the radiation modifies the refractive index of the PMMA forming core and cladding regions for waveguiding. Following the fabrication of the waveguides, the small molecule material aluminum tris(8-hydroxyquinoline) doped with the laser dye DCM is deposited directly onto the waveguide structures. By optical pumping (lambda=355 nm) amplified spontaneous emission was observed at the end facets of the waveguides

Material Investigation of Alicyclic Methacrylate Copolymer for Polymer Waveguide Fabrication

We investigated the physical and chemical properties of alicyclic methacrylate copolymers and their changes under deep-UV exposure. It was shown that alicyclic methacrylate copolymers have a better thermal stability and a higher refractive index than conventional poly(methyl methacrylate) (PMMA). Fourier transform IR (FTIR) spectra show the scission of the carbonyl group of the alicyclic methacrylate copolymers by deep-UV exposure similar to that of PMMA. This structural modification results in a local and controllable increase in refractive index in the exposed areas of the polymer surface. We fabricated polymer waveguides from alicyclic methacrylate copolymers by conventional photolithography using quartz/chromium mask. The minimum propagation loss of the straight waveguide with a 7.5 µm width was 2 dB/cm at 1550 nm.

Replication of optical rib waveguide structures using nickel shims

The use of conventional fabrication techniques for the fabrication of polymer based photonic integrated waveguide circuits is a necessary step to reduce costs. The replication of rib waveguides is presented using nickel shims. Results of replicated waveguides and 1 x 2 multimode interference (MMI) couplers are shown.

A modular microfluidic backplane for control and interconnection of optofluidic devices

A modular microfluidic backplane with integrated microvalves enabling the flexible interconnection, supply, and control of optofluidic devices has been fabricated from polymers in two designs, providing two- or three-dimensional device assemblies.

Determination of living cell characteristics and behavior using biophotonic methods

This paper describes the development of methods for the determination of the characteristics and the behavior of living neural cells. A technology which is used is the deep ultraviolet (DUV) modification of methylmethacrylate polymers which leads to a new surface chemistry affecting the selective absorption of proteins and the adhesion of living cells in vitro. The bi-functionality of the modified polymer chips supporting waveguides and cell anchorage capabilities at the same time provides the opportunity to monitor protein adsorption, cell attachment and spreading processes by evanescent-field techniques. This allows the defined spatial control of a cell/surface interaction and leads to a combination of desired biological and optical properties of the polymer. Among them are the high sensitivity of cultured mammalian cells to, for example, environmental changes and special features of integrated optical waveguides like their online compatibility, minuteness and robustness. The scientific fields, biology and optics, meet at the polymer surface becoming a cell culture substrate together with an optical waveguide by the application of special patterning and fabrication technologies. In addition to the already mentioned fabrication and immobilization technology, the technique proposed also offers the possibility of being able to couple to microstamping processes and to also incorporate electrical measurements on individual cells. Thus, by extending this method and coupling it to the DUV technique described above the possibility is given of being able to simultaneously optically and electrically interrogate individual cellular processes with spatial resolution.