Amin Khorshidahmad

Composite superprism photonic crystal demultiplexer: analysis and design

We present the analysis and design of a superprism-based demultiplexer that employs both group and phase velocity dispersion of the photonic crystal (PhC). Simultaneous diffraction compensation and spatio-angular wavelength channel separation is realized in a slab region that divides the PhC. This avoids the excessive broadening of the beams inside the PhC and enhances the achievable angular dispersion of the conventional superprism topology. As a result, a compact demultiplexer with a relaxed requirement for low divergence input beams is attained. The dynamics of the beams envelops are considered based on the curvature of the band structure. Analysis shows at least 36-fold reduction of the PhC area and much smaller propagation length in slab compared to the preconditioned superprism, based on the same design model. PhC area scales as Δω(-2.5) with Δω being the channel spacing.

Wavelength conversion by dynamically reconfiguring a nested photonic crystal cavity

A dynamically reconfigurable nested photonic crystal cavity suitable for frequency conversion applications is proposed. Dynamic switching between two distinct cavities allows intermodal transition via spatially-uniform tuning of the refractive index. Exclusion of the initial resonant mode from the Eigen modes of the tuned cavity precludes the adiabatic wavelength conversion process. Multiple intermodal transitions are suppressed by the symmetry of the mode profiles of the two cavities. Over 90nm wavelength shift (from L-band to the S-band) is shown numerically.

Nested photonic crystal cavity for on-chip wavelength conversion

we propose a nested photonic crystal cavity configuration for on chip wavelength conversion based on adiabatic tuning of the resonator whereby dynamic switching between two cavity structures significantly extends the achievable frequency conversion range.

Wavelength conversion by interband transition in a double heterostructure photonic crystal cavity

Optical wavelength conversion over an ultrawide spectral range based on an intermodal transition induced by dynamic tuning of a double heterostructure photonic crystal cavity is numerically demonstrated. Exploiting the inherently large spectral separation between the eigenmodes and the field symmetries to suppress multiple mode couplings, a normalized wavelength shift of about 25% with feasible index tuning is achievable by coupling only two resonances.

Reflective Heterostructure Photonic Crystal Superprism Demultiplexer

A new design for a wideband and compact demultiplexer for coarse wavelength-division-multiplexing applications is proposed. This is based on the superprism effect, using diffraction compensation in a stratified hetero-lattice photonic crystal (PhC) operating in reflective mode. Modeling the variation of the beam envelope within the hetero-lattice, an optimum eight-channel design with 20-nm wavelength spacing is feasible within 42000 μm2 of PhC area. The design results in almost diffraction-limited output beams, and provides a size reduction of 2.6 to 7 times when compared to the PhC area required in the homo-lattice SP design.

Scheme for in-plane pumping of a photonic crystal heterostructure cavity

Based on the concept of mode-gap confinement, we propose a cross-shaped heterostructure photonic crystal cavity incorporating an intersecting waveguide for direct in-plane pumping of the cavity via the mode of the crossing waveguide.

Stratified Photonic Crystal Demultiplexer

A wide-band CWDM demultiplexer using cascaded photonic crystal geometry is proposed. Five-fold superprism size reduction is achieved when compared to the conventional S-vector superprism. The output channel beam sizes are also much more uniform

1-D Photonic Crystal as an Anti-Reflection Layer for First Band Photonic Crystals

A 1-D photonic crystal (PC) when placed in front of a bulk PC can play the role of anti-reflection layer (ARL). A five-fold reduction in reflection is obtained for a first band PC

Tunable multi-wavelength source based on a nested heterostructure photonic crystal cavity

Wavelength-spacing tunable multi-wavelength source by controlling the intermodal transitions induced via dynamic reconfiguration of a nested photonic crystal cavity, through optically induced free carriers, is proposed. Optical combs spanning the entire C-band are demonstrated numerically.

Multi-wavelength Generation via a heterostructure cavity embedded in a photonic crystal ring

Multi-wavelength Generation, by intermodal transitions induced via dynamically reconfiguring a heterostructure cavity embedded within a photonic crystal ring resonator, is proposed. Tailoring the structure, 13 generated frequencies spanning the S-L bands are demonstrated numerically.