An optical transceiver formed onto a conventional low-cost printed circuit board with integrated optical waveguides is
presented. The transceiver incorporates an optical multimode polymer Y-splitter formed directly on a low-cost singlelayered
FR4 substrate enabling duplex transmission along a single optical fibre. The transmitter and receiver assemblies
are mounted onto the board using methods common to conventional PCB manufacturing. Simple through-board
connectors, compatible with pick-and-place assembly technology, are used to interface the electrical and optical layers of
the board. This approach allows end-fired optical coupling between the active devices and optical waveguides on the
board. The demonstrated transceiver, intended as a board-level optical network unit, achieves error-free data
transmission for both Tx and Rx modules at 10 Gb/s.
The first realistically photon-like Schrödinger solution of Maxwell's classical equations in dispersive media is presented.
Classical modes of transverse electric or transverse magnetic fields with angular frequency ω propagating along an axis
are shown to be able to be enveloped with counter-rotating helical modulations which have a different angular frequency
Ω. These helical rotations, called distributed spin rotations, propagate at the group velocity. The formation of a
completely closed packet of electromagnetic energy requires that the axial fields and transverse fields have a common
axial length of envelope. This forces Ω to take quantized values in terms of ω with Ω related to the Schrödinger frequencies of a harmonic oscillator. The spin rotations permit flexible transverse confinement allowing for localization of the photon wave-packet over different spatial areas. It is argued that the energy of this packet is not related to its
volume but depends on the quantized helical frequency Ω. Such photon-like packets possess classical phase and group
velocities in keeping with experimental evidence. A single photon-like packet does not disperse in dispersive media.
Incrementing or decrementing the rate of helical rotation promotes or demotes the packet energy in keeping with
standard photon theory. The model offers explanations for self-interference and entanglement.
This paper presents an overview of multimode waveguides and waveguide components formed from siloxane polymer
materials which are suitable for use in optical interconnection applications. The components can be cost-effectively
integrated onto conventional PCBs and offer increased functionality in optical transmission. The multimode waveguides
exhibit low loss (0.04 dB/cm at 850 nm) and low crosstalk (< -30 dB) performance, large alignment tolerances and
negligible mode mixing for short waveguide lengths. Error-free data transmission at 10 Gb/s over 1.4 m long waveguides
has been successfully demonstrated. Waveguide crossings exhibit very low excess losses, below 0.01 dB/crossing, and
excellent crosstalk performance. Low loss is obtained for waveguide bends with radii of curvature larger than 8 mm and
6 mm for 90° and S-shaped bends respectively. High-uniformity splitting is achieved with multimode Y-splitters even in
the presence of input misalignments. Y-combiners are shown to benefit from the multimode nature of the waveguides
allowing low loss combining (4 dB for an 8×1 device). A large range of power splitting ratios between 30% and 75% is
achieved with multimode coupler devices. Examples of system applications benefiting from the use of these components
are briefly presented including a terabit capacity optical backplane, a radio-over-fibre multicasting system and a SCM
passive optical network.
This paper presents a design for rectangular ring resonators based on low-index polymers operating at an 850 nm
wavelength. Multimode interference couplers are used to enable signal splitting and combining and air trench assisted
90° mirrors are used as beam turning elements. 3D full-vector, 2D FDTD and parameter models are combined to
simulate the ring resonator design. This design, suitable for spectral shaping, achieves a FSR of 0.29 nm, a FWHM of
0.066 nm and an on-off ratio of approximately 20 dB.
In this work the recent interest in waveguides for use in short optical links has motivated a study of the modal noise
dependence on launch conditions in short-reach step-index multimode polymer waveguides. Short optical links,
especially those with several connection interfaces and utilising a restricted launch are likely to be subject to a modal
noise power penalty. We therefore experimentally study the modal noise impact of restricted launches for a short-reach
optical link employing a 50 x 50 μm polymer multimode waveguide. Lens launches resulting in small diameter input
spots are investigated as are restricted launches from an 8 μm core optical fibre. For a launch spot of 10 μm diameter no
impairment is observed for up to 9 dBo of mode selective loss, and for a fibre launch with a dynamic input movement of
6 μm no impairment is seen for up to 8 dBo of mode selective loss.