In this work, we design a 60-degree waveguide bend with a wide high-transmission bandwidth (~ 9.8% of the center
frequency, or 150 nm at the wavelength of 1550 nm) in a triangular photonic crystal slab. Within the high-transmission
bandwidth, power reflection at the bend is found to be lower than 2% of the input power. Based on this 60-degree bend,
a sharp 120-degree bend with a compact device area is proposed. Similar transmission efficiency is also found for this
120-degree bend.tis@ep
The conventional approach to calculate the transmission and reflection spectra of a photonic crystal (PC) waveguide
device by the finite-difference time-domain method is both time and memory demanding. Here we propose a more
efficient approach to obtain these spectra. First, the PC-based absorbing boundary condition is employed. Second, the
reflected pulse is obtained by subtracting from a reference waveform. For a T-junction in square lattice PC, a
computational cell of 40 x 36 lattice constants can be used instead of 180 x 140 lattice constants. The simulation time is
reduced to only one tenth of that using the conventional approach.
In this paper, we propose a polarization beam splitter (PBS) for two-dimensional photonic crystal (2D PhC) self-collimation
devices. By engineering the PhC dispersion characteristics, both transverse magnetic (TM) and transverse
electric (TE) light can propagate collinearly in the same PhC by self-collimation phenomena. Either one or two defect
regions are designed to pass the TM light and to reflect the TE light such that the two polarizations can be efficiently
separated into different output ports. The finite-difference time-domain (FDTD) method is employed to assess the device
performance. Polarization extinction ratios (PERs) between the two output ports are 25.4 dB and 31.8 dB for TM and TE
inputs, respectively. This PBS also exhibits a large operating wavelength range (PER > 20 dB) covering all over the
optical C-band and L-band. Fabrication tolerance for the radius of air holes is approximately 10 nm. Moreover, the size
of the PBS is only 24 μm x 18 μm and can be even more compact for a lower PER.
Single-mode polarization splitter with a configuration of asymmetric Y-junction is proposed in two-dimensional (2D) honeycomb photonic crystal (PhC) of dielectric rods. Six dielectric rods with a radius of 0.12a (The radius of a regular rod is 0.25a.) are placed on the junction region to block transverse magnetic (TM) light and to pass transverse electric (TE) light by the bandgap effect, where a is the shortest distance between two regular rods. And one rod with a radius of 0.32a is employed to enhance the bending efficiency of TM light through a resonance effect. Device performance is simulated by the finite-difference time-domain method. At 1550 nm wavelength, polarization extinction ratio (PER) between the two output waveguides is larger than 20 dB for either TE or TM input. Polarization splitting as a function of wavelength is also studied in this paper.
Two-dimensional 1×3 photonic crystal power dividers in a square lattice of dielectric columns are proposed for equal-power
splitting at 1.55 μm wavelength. Dielectric columns having different radius are used for impedance matching such
that high power transmission and equal-power division can be realized. Two proposed structures having normalized total
transmitted powers as large as 0.99 are successfully designed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.