Generic Photonic Integration Platform Research Articles

Voltage-Driven Near Field Beam Shifting in an InP Photonic Integrated Circuit

A voltage-driven, continuously-tuned beam shifting device is proposed, simulated, and demonstrated in an InP photonic integrated circuit. Electrodes are applied on the left and right side of a mode-expanded waveguide to electronically control the refractive index profile and shift the optical beam by means of reverse bias voltage. The feasibility of a beam shifting of 4.9 μm with a power consumption of the order of 4.5 pW and voltage of 10 V is numerically predicted for a beam shifting element with ideal electrical isolation and fundamental input mode excitation. The reduction in beam-shifting efficiency is subsequently quantified for imperfect electrical isolation and in the presence of higher order mode excitation at the input to the beam shifting element. An experimental proof of concept is implemented by realizing the device on a generic photonic integration platform and co-integrating an on-chip tunable laser. High-resolution near-field measurements show near-field beam shifting of 1 μm with an applied voltage range from -4 to 0 V.

Directional power distribution and mode selection in micro ring lasers by controlling the phase and strength of filtered optical feedback.

We discuss the design and characterization of a micro ring laser with on-chip filtered optical feedback. The laser and feedback section have been fabricated on a generic photonic integration platform using only standard building blocks. The filtering process in the feedback scheme is based on the reflection from a distributed Bragg reflector. We include several control pads in the feedback section which allows us to control separately the wavelength, the strength and the phase of the filtered feedback. By controlling the phase of the feedback, we can fine-tune the longitudinal mode selection and wavelength of the laser output, while changing the strength of the feedback allows us to control the power distribution between the two directions of the micro ring laser. Numerical simulations reproduce our experimental observations.

Random number generator based on an integrated laser with on-chip optical feedback.

We discuss the design and testing of a laser integrated with a long on-chip optical feedback section. The device and feedback section have been fabricated on a generic photonic integration platform using only standard building blocks. We have been able to integrate a 10 cm feedback length on a footprint of 5.5 mm2. By controlling the amount of feedback, we achieve chaotic dynamics in the long-cavity regime and show that the resulting dynamics is sufficiently complex in order to generate random bits based on the chaotic intensity fluctuation at a rate of 500 Mbits/s.

AlGaInAs MOVPE selective area growth for photonic integrated circuits

Abstract We developed a generic photonic integration platform based on selective area growth (SAG) by metal organic vapor-phase epitaxy (MOVPE) of AlGaInAs/InP multiple quantum well (MQW) material. For efficient and predictive band gap engineering of photonic integrated circuits, different SAG zones of active and passive function heterostructures are precisely modeled and characterized. With the vapor-phase diffusion model, using numerical simulations of finite volumes, we extracted the three effective diffusion lengths of Al, Ga, and In species. In our growth conditions, these lengths were 32, 65, and 14 μm, respectively. The Kardar-Parisi-Zhang (KPZ) equation, a classic approach to describe the growing interface profile, is used. AlGaInAs MQW properties are then simulated in terms of thickness, composition, band gap, and biaxial strain variations. Highly resolved μ-photoluminescence and optical interferometer microscopy measurements confirm the validity of the band gap and thickness variations for both bulk and MQW layers. A new diffractometer, with a submillimeter X-ray spot, was used to study the structural properties of the MQW in the center of the SAG area. As an application, we present the realization and operation of full-monolithic high-speed advanced modulation format transmitters based on novel prefixed optical phase switching by fast electro-absorption modulators.

Microwave Photonic Integrated Circuits for Millimeter-Wave Wireless Communications

This paper describes the advantages that the introduction of photonic integration technologies can bring to the development of photonic-enabled wireless communications systems operating in the millimeter wave frequency range. We present two approaches for the development of dual wavelength sources for heterodyne-based millimeter wave generation realized using active/passive photonic integration technology. One approach integrates monolithically two distributed feedback semiconductor lasers along with semiconductor optical amplifiers, wavelength combiners, electro-optic modulators and broad bandwidth photodiodes. The other uses a generic photonic integration platform, developing narrow linewidth dual wavelength lasers based on arrayed waveguide gratings. Moreover, data transmission over a wireless link at a carrier wave frequency above 100 GHz is presented, in which the two lasers are free-running, and the modulation is directly applied to the single photonic chip without the requirement of any additional component.