High-speed semiconductor waveguide phase-shifter

Abstract

An optical phase shifter (100) comprises a semiconductor waveguide (105) includes a core region (116) and a doped region (115a, 115b) containing free charges (electrons or holes), which can be steered into or removed from the wave guide, where an optical beam (150) propagates. A semiconductor structure (PN junction 112, 114) allows the control of the amount of free charges in the doped region, which constitutes a potential well. When the well is filled, the charges speed the beam propagation, introducing a phase change. When the well is emptied, (under application of a reverse bias to the junction 112, 114), the beam propagates with extra delay. The phase shifter allows very high speed modulation of the beam using low voltage and low power electronics. The device can be created using standard silicon processing techniques, and integrated with other optical components such as splitters and combiners to create amplitude modulators, attenuators and other optical devices.

Description

[0001] Cross references to related applications [0002] This application is based on and claims the priority of the following applications: U.S. Provisional Patent Application No. 60 / 601,723, which was filed on August 16, 2004 and incorporated herein by reference in its entirety; and U.S. Patent Application No. 11 / 161,744, which was submitted on August 15, 2005 and its entire contents are incorporated herein for reference. Technical field [0003] The present invention relates to the field of high-speed optical communication, and in particular, to a phase shifter device that can change the phase of an optical signal according to an electrical signal. Background technique [0004] The intensity of the light beam is often modulated to encode data in optical communications. This amplitude modulation can be achieved by combining the replication of the selectively delayed beam with itself. When the copy of the beam is delayed by π radians and combined with the original beam, destructi...

AI Technical Summary

Problems solved by technology

Lithium niobate (LiNbO 3 ) modulators can be fast and have reasonable voltage requirements, however, they cannot be polarized individually and are not suitable for integration of drive electronics and optics

Integrated doped silica waveguides, also known as silicon optical bench components, offer polarization independence and high integration, however, their maximum switching speed is only in the 1MHz range

Semiconductor modulators (InP or GaAs) can have 40GHz bandwidth; however, polarization independence and mass integration of multiple channels and other components is not easily achieved with this technology

Silicon modulators consisting of silicon waveguides embedded in silica allow high-volume integration; however, designs to date have rather low phase variation per unit voltage and length, requiring either high operating voltages or large device

Many existing designs also consume a high degree of static power, such as P-I-N devices, which have a continuous current flow through the device in order to maintain a stable carrier concentration

Images