Geetika Jain

Gain calculation in erbium-doped LiNbO3 channel waveguides by defining a complex index profile

An analysis of erbium-doped titanium indiffused LiNbO3 channel waveguides under 1484-nm excitation is presented in terms of a complex refractive index profile under 1484-nm excitation (pump) to obtain modal gain and loss for signal and pump powers, respectively. Closed form analytical expressions for modal fields are used to define the complex index profile. The calculated gain characteristics are compared with available experimental results.

Closed-form modal field expressions in diffused channel waveguides

We present accurate closed form expressions for modal fields and propagation constant of the fundamental mode in diffused channel waveguides using a scalar variational approach. The results have been compared with those obtained by use of the Optiwave BPM_CAD software package. The closed form fields have been shown to be useful in optimizing fiber to waveguide coupling and evaluating gain in Erbium doped waveguides.

Er-LiNbO 3 waveguide: field approximation for simplified gain calculations in DWDM application

The coupled differential equations, which govern the evolution of pump and signal power in the gain characterization of Er-doped diffused channel waveguides, involve integrals that depend explicitly on the modal fields at the pump and all signal wavelengths. We use an analytical form of the modal field as an appropriately chosen buried asymmetric Gaussian function centered at the field maximum; this leads to analytical forms of coupled differential equations with no integrals for the calculation of gain characteristics of the amplifying waveguide. Thus, computations are simplified and computation time is also significantly reduced.

Silicon Sensors in Experimental High Energy Physics Experiments

Si detectors are now being widely used in experimental high energy physics (HEP). This detector technology is more popularly used as particle tracking detectors. Its application is diverse, viz. from the track reconstruction, various parameters of the incident particle like the flight of path, the momentum in the presence of a magnetic field, secondary or a decay vertex, interaction vertex, etc., can be deduced. Si detectors are also used as active layers in sampling calorimeters in some of the experiments.

Study of Trapping Probability in Proton Irradiated Silicon Pad Detectors Using Transient Current Technique Simulations

As the rate of the incoming fluence increases, the density of the traps also increases in the silicon bulk. This leads to a decrease in the charge collected limiting the long term operation of the silicon detectors. In the work presented here, we have calculated the effective trapping probability in a proton irradiated silicon pad detector using transient current simulations and ROOT software.

Synthesis of titanium indiffused LiNbO3 waveguides with desired modal fields

In this paper we report a procedure based on variational approximation, to obtain the refractive index profile and process parameters for fabrication of waveguide from the desired modal field. We have illustrated our procedure by the design of a diffused channel waveguide for optimum coupling to a standard communication grade fiber.