49 research outputs found
Modal and Polarization Qubits in Ti:LiNbO Photonic Circuits for a Universal Quantum Logic Gate
Lithium niobate photonic circuits have the salutary property of permitting
the generation, transmission, and processing of photons to be accommodated on a
single chip. Compact photonic circuits such as these, with multiple components
integrated on a single chip, are crucial for efficiently implementing quantum
information processing schemes. We present a set of basic transformations that
are useful for manipulating modal qubits in Ti:LiNbO photonic quantum
circuits. These include the mode analyzer, a device that separates the even and
odd components of a state into two separate spatial paths; the mode rotator,
which rotates the state by an angle in mode space; and modal Pauli spin
operators that effect related operations. We also describe the design of a
deterministic, two-qubit, single-photon, CNOT gate, a key element in certain
sets of universal quantum logic gates. It is implemented as a Ti:LiNbO
photonic quantum circuit in which the polarization and mode number of a single
photon serve as the control and target qubits, respectively. It is shown that
the effects of dispersion in the CNOT circuit can be mitigated by augmenting it
with an additional path. The performance of all of these components are
confirmed by numerical simulations. The implementation of these transformations
relies on selective and controllable power coupling among single- and two-mode
waveguides, as well as the polarization sensitivity of the Pockels coefficients
in LiNbO
10-GB/S transmission over 1400 km on G.652 fiber with dispersion compensation by chirped FBG
Velocity-mismatch compensated spread spectrum traveling-wave modulators using pseudorandom switched electrode patterns
The wavelength dependence of a synthesized electro-optic co-directional-coupler modulator with π-phase shifters
Reduction of the Signal Nonlinear Distortion in CATV Systems applying Dual Mach-Zehnder Modulators
High quality pulse and device characterisation using EAM-based frequency resolved optical gating
We report on the versatility of frequency resolved optical gating using an electro-absorption modulator to accurately characterise the pulse shape and phase of high speed telecommunication pulses, as well as properties of optical components