Fluorinated Epoxy waveguides doped with Nd complexes have been studied for optical amplification applications. The
fluorescent complex was Nd(TTA)3phen (TTA = thenoyltrifluoroacetone, phen = 1, 10-phenanthroline), which was
mixed with the host material 6-FDA (6-fluorinated-dianhydride ). The solution was spin coated in order to obtain
Nd(TTA)3phen-doped 6-FDA/epoxy slab and channel waveguides. The emission spectra of the Nd-complex doped
waveguides were measured at different pump powers by pumping at 800nm, and emission was observed at 890nm,
1060nm and 1330nm. The luminescence lifetime of the Nd complex within the waveguides was experimentally
determined. The results demonstrate that the neodymium ions within the polymer host have good transition properties.
Based on experimentally obtained parameters the optical gain of the Nd-complex doped waveguides was estimated with
the aid of rate equations. The results show that Nd complex doped polymer waveguides are promising gain media for
Different electro-optic polymer systems are analyzed with respect to their electro-optic activity, glass transition
temperature (Tg) and photodefinable properties. The polymers tested are polysulfone (PS) and SU8. The electro-optic
chromophore, tricyanovinylidenediphenylaminobenzene (TCVDPA), which was reported to have a high photochemical
stability 1 has been employed in the current work. Tert-butyl-TCVDPA, having bulky side groups, was synthesized and a doubling of the electro-optic coefficient (r33) compared to the unmodified TCVDPA was shown. A microring resonator
design was made based on the PS-TCVDPA system. SU8 (passive) and TCVDPA (active) channel waveguides were
fabricated by the photodefinition technique and the passive waveguide losses were measured to be 5 dB/cm at 1550 nm.
In the last years much effort has been taken to arrive at optical integrated circuits with high complexity and advanced functionality. For this aim high index contrast structures are employed that allow for a large number of functional elements within a given chip area: VLSI photonics. It is shown that optical microresonators can be considered as promising basic building blocks for filtering, amplification, modulation, switching and sensing. Active functions can be obtained by monolithic integration or a hybrid approach using materials with thermo-, electro- and opto-optic properties and materials with optical gain. Examples are mainly taken from work at MESA+.
Polymeric optical waveguide components offer attractive properties for applications in optical telecom and datacom systems. These are high speed for electro-optic modulators, low power dissipation for thermo-optic (digital) switches and low-cost for all active and passive components. We report on active and passive components realized by utilizing polymer-specific attractive techniques such as planarizing spincoating, low-temperature reflowing and direct photodefinition. Examples are multimode photodefined passive polymeric waveguides for optical interconnect applications; photodefined monomode polymeric waveguides loaded with rare-earth doped nanoparticles for planar waveguide amplifiers and with non-linear chromophores for electro-optic modulators. We will show that polymer waveguide technology allows vertical stacking of electro-optic microringresonators with their port waveguides to realize high-speed modulators. By reflowing the reactive-ion-etched microring we could reduce the scattering by wall roughness considerably. Thermo-optic polymeric microringresonators combine the high thermo-optic coefficient and low thermal conductivity of polymers with the small size of the microring. It will be shown that this yields a broad wavelength tuning range at low power dissipation.
The hybrid integration of polymer and silica in optical waveguides can yield devices that combine the excellent thermo-optic properties of polymers and the superior passive waveguiding properties of silica. The large difference and opposite sign of the thermo-optic coefficients of both classes of materials can be utilized to create athermal waveguide devices. In addition, it can be utilized in thermo-optic devices to induce local changes in the refractive index with boundaries that are sharply defined by the material interfaces and not by gradual thermal profiles. This can also yield devices with attractive thermo-optic behavior.
This paper describes the implementation and investigation of an all-optical amplified ring network with Phased Array based optical add/drop multiplexers (OADMs). From crosstalk analysis follows that an OADM with a foldback-structure and 1 X 2-switches has an outstanding crosstalk performance. From the investigation of the dynamic behavior of Erbium doped fiber amplifiers (EDFAs) in a ring configuration we found that EDFAs in a ring-configuration require a faster gain-control when compared to a cascade-configuration.
Modal dispersion phase-matched second harmonic generation is demonstrated in polymer-based waveguides with a nonlinear optical core consisting of two side-chain polymers with different glass-transition temperatures. For an optimized overlap integral, a step like nonlinearity profile (chi(2)-inverted structure) is required across the core thickness. The chi(2)-inverted structure is achieved by two consecutive thermally assisted poling steps above and between the respective glass-transition temperatures, with an opposite poling field in the second poling step. The achieved chi(2)-inverted structure is monitored by in- situ electro-optic measurements and proved by electro-optic and second harmonic generation thermal analysis. Conversion efficiencies up to 7%/Wcm2 were achieved in first waveguide second-harmonic generation experiments.
Recently developed photobleachable polymers show a loss of < 0.1 dB/cm at 1300 nm and < 0.15 dB/cm at 1550 nm. Nonchromophore containing polymers show film waveguide losses of < dB/cm at 1300 nm and 1550 nm. Refractive indices in these materials can be tuned within a range of 0.05 by changing the polymer composition. Multilayers of cross-linked (solvent resistant) layers, each 2-10 microns have been deposited by multiple spinning steps. Using these multilayers, fully embedded, fiber-compatible strip waveguide structures have been created by masked bleaching of multilayers with chromophore containing corelayers. The lateral refractive index contrast is thereby tuned by changing the chromophore content of the corepolymer. Poling-induced loss has been investigated by wavelength and polarization dependent measurements of losses in films. The results indicate that this loss is due to increased scattering. Bleached channel waveguides in a poled (at 125 V/micrometers ) nonlinear optical polymer have been made showing losses of < dB/cm at 1300 nm. Rapid photodegradation at 1300 nm has been observed in stilbene containing channel waveguides. In a nitrogen atmosphere no degradation was seen. The same is true for waveguides in air at 1550 nm. This suggests the attack of the stilbene chromophores by singlet oxygen. Therefore a new generation of low-loss, linear, and nonlinear optical polymers based on singlet oxygen resistant molecules has been developed. The linear optical polymers are used for the realization of low-insertion loss (< 2 dB), digital (switch voltage 3-6 V) and efficient (switching power < mW, cross talk - 20 dB) pigtailed and packaged 1 X 2 switches. They utilize the strong thermo-optic effect in polymers. Their switching time is therefore limited to 1 ms whereas their polarization dependence is < 0.3 dB.
Two nonlinear optical polymers, containing the active molecules in the main-chain and in the side-chain, have been characterized by dielectric spectroscopy in the frequency range from 0.05 Hz to 10 kHz. It is shown that dielectric spectroscopy is a powerful technique to monitor the mobility (relaxation) of active molecules. From the results a estimation about the poling temperature and -time can be made. In addition, the influence of absorbed water on the relaxation is established as well as the effect of UV-light exposure on the chromophores.
A digital thermo-optic (t.o) 2X2 switch based on nonlinear optic (nlo) polymer is presented. The switch exploits a favorable combination of several attractive properties of nlo- polymers: a strong sensitivity for photochemical bleaching, a poor heat conduction and a large t.o.-effect. The bleaching is used to fabricate optical channel waveguides. Mode-sorting waveguides are used to obtain a digital switching behavior. Switching is performed by utilizing the t.o.-effect. For polymers this effect is an order of magnitude larger than for other materials used in integrated optics. The poor heat conduction of polymers results in switching with a low power dissipation.
Optically nonlinear side chain polymers have been used to make a number of polymeric electro-optic and thermo-optic switching devices. The following devices are described and their performances discussed: a 2 X 2 electro-optical directional mode coupler; a 1 X 2 Mach-Zehnder switch comprising a Y-splitter combined with 2 parallel arms and a directional coupler section; a polarization and wavelength independent switch comprising a Y- junction; and an electro-thermo-optical Mach-Zehnder interferometer. In addition, the stability of some of the devices is presented and discussed. The directional mode coupler shows -17 dB modulation depth for 7.5 Volts switching voltage; the Mach-Zehnder switch required 10 Volts for 14 dB switching ratio; the Y-junction switch needed 50 mW for >20 dB modulation; the electro-thermo-optical Mach-Zehnder required as low as 0.5 mW to achieve (pi) -phase shift. The results show that optically nonlinear side chain polymer are attractive materials for the realization of polymeric switching devices.
Side chain polyrrers containing hyperpolarizable noieties as the periant groups have been applied as
optically ncrilinear traterials to produce polyxreric integrat1 electro-optical devices . Phase nixiulators,
intisity nixiulators (1ch-Zebzx1er interferaiters) aixi optical 2*2 sce switches ( 2*2 directixa1 nixie
couplers) have been uncle . Driving voltages as 1ci as 2 Volts (V ) have been obtain1 for a 24 nm active
1gth çkmse ncdulator; 4.4 Volts (V ) for a 14 inn active 1angthch-Zebrx1er interferarter, ath 9 Volts
for a 14 nm active length directionI node ccupler. Intisity nixiulation ratios of about -23 dB atti -17
dB have been derived for the intensity nixiulator atd nixie ccxipling switch, respectively. The device
properties , theni.l arxi electrical stabilities , etc. will be discussed. The results obtained shcw that
optically txnlinear polyiTers are attractive caixlidates for the realizaticzi of polyireric integrated
electro-optical devices. In additicn, several passive veguiding devices have beai nnde.