H. P. Chan

Polymer planar waveguide device using inverted channel structure with upper liquid crystal cladding

We propose a composite waveguide configuration based on an inverted polymer channel structure with upper nematic liquid crystal cladding. This configuration can achieve a more homogenous liquid crystal molecular alignment between the core and the liquid crystal material by minimizing the rubbing damage during preparation of the alignment layer. We demonstrated our idea with a variable optical attenuator which exhibited a 24 dB of attenuation range over a tuning peak voltage of 10 V at 1550 nm.

Ultraviolet writing of buried waveguide devices in epoxy-coated benzocyclobutene

We propose a simple ultraviolet (UV) writing technique for the fabrication of buried waveguide devices, which employs a UV lamp as the light source and commercial benzocyclobutene (BCB) and epoxy OPTOCAST 3505 as the core and cladding materials, respectively. We show that the light emitted from the UV lamp can induce a large refractive-index change (up to 0.012) in BCB, while a negligible index change in the epoxy, which makes possible the writing of buried waveguide devices in BCB by exposing an epoxy-clad BCB film to the UV light through a mask. We demonstrate this technique experimentally with straight channel waveguides, Y-junction waveguide branches, and long-period waveguide gratings. The propagation loss of a typical fabricated waveguide is 1.6 dB/cm at 1550 nm and the polarization-dependent loss is 0.4 dB/cm.

Imprinting of thermo-optic polymer-waveguide Mach-Zehnder interferometer with bottom-up electric heating

We demonstrate a new approach of fabricating a thermo-optic polymer-waveguide Mach-Zehnder interferometer (MZI). The MZI is fabricated with an imprinting technique, where the electrode heater is formed at the bottom of the waveguide substrate.

Fabrication of a polymer based variable optical attenuator using liquid crystal cladding on inverted channel waveguide structure

Using nematic liquid crystal as the upper cladding of inverted polymer waveguide structure, we fabricated a variable optical attenuator which exhibited a 24 dB of attenuation range with a tuning range of 10 Vpeak at 1550 nm.

UV-written long-period waveguide grating coupler

We present a UV-written polymer long-period waveguide grating coupler, which can be tuned over a wavelength range of 100 nm with a temperature control of 22 degC. Its coupling efficiency varies between 57% and 80%.

A flat-top pass-band interleaver through two-stage Y-Junction MZI on polymer PLC platform

A two-stage-cascaded Y-Junction MZI interleaver of 100 GHz channel spacing over a 40 nm wavelength window is experimentally demonstrated. The 0.5 dB pass -band at the two output ports were 38 GHz and 50 GHz , respectively.

Relaxation in alignment tolerance by double-side irradiation induced self-written waveguide for passive optical packaging

A simple low-cost technique to relax the alignment tolerance between fiber coupling by double-side-irradiation induced self-written-waveguide is proposed and demonstrated. By this technique, up to 4µm misalignment-tolerance is achieved with only 1 dB extra-loss penalty.

Experimental investigation of electro-optic long-period gratings on lithium-niobate waveguides

Using several electro-optic long-period grating s fabricated on LiNbO3 wave guides, we demonstrate the effects of the cladding modes and the waveguide structure on the grating performance. We obtain a 25-dB rejection band at 95-V driving voltage.

Dye-doped polymer based self-written waveguide for optical interconnection

For long term & stable properties of the packaged optical devices, a suitable optical interconnection method is highly required in photonic manufacturing. It is mainly used to provide a better optical property to the packaged device and to prevent from the atmospheric effect. As an optical interconnection, the formation of self-written waveguide (SWW) in dye-doped polymer by irradiation of green laser is demonstrated. The formed SWW is characterized by measuring the output power through the interconnection. The reliability is also tested with the lateral displacement conditions. The applied lasing power and the dye composition ratio were found as the most influencing factors in SWW formation. The effect of those factors is carefully studied and optimized.

Mach-Zehnder Electro-Optic Modulator Based on Epitaxial Ba0.7Sr0.3TiO3 Thin Films

Epitaxial Ba 0.7 S r 0.3 TiO 3 (BST) thin films were deposited on MgO (001) single crystal substrates using pulsed laser deposition. The bidimensional structure of a rib-type Mach-Zehnder electro-optic modulator was designed using the effective index method. A Mach-Zehnder electro-optic modulator based on BST/MgO was fabricated using standard photolithography and reactive ion etching techniques. A single mode near-field output pattern was observed using an end-fire coupling method. Optical modulation was successfully demonstrated. The half-wave voltage V π was found to be 60 V and the effective electro-optic coefficient was calculated to be r c eff = 27.0 × 10−12 m/V at a wavelength of 1550 nm.