Abstract:
An optical to radio frequency detector comprising an optical guide (11 to 14) for receiving two optical singal components having frequencies that differ by an amount corresponding to a radio frequency, and a radio signal guide (15, 16) coupled with an interaction zone (14) of the optical guide for propagating a radio signal from the interaction zone at the radio frequency. the interaction zone (14) of the optical guide comprises an interaction material presenting a second-order non-linear optical polarisation characteristic to the propagatio of the optical singal components, and the radio signal guide (15,16) is in travelling-wave coupling with the interaction zone. the interaction material includes electrically orientated diazobenzene. The radio signal guide (15,16) comprises an electrically conductive strip (15) juxtaposed with and extending along the interaction zone (14) on one side thereof and an electrically conductive ground plane (16) juxtaposed with and extending along the interaction zone (14) on an opposite side thereof.
Abstract:
The invention relates to an electroabsorption modulator (EAM) (300), comprising a first EAM section (302) optically coupled to a second EAM section (304), a transition wavelength in the electroabsorption (EA) spectrum of the first EAM section (302), at which absorption changes substantially, being different to a transition wavelength in the EA spectrum of the second EAM section (304). The EAM (300) compensates for chirp (which is caused by intrinsic absorption effects) by driving the two sections with a signal (312) generated from a common modulating signal (314). The driving signal (312) at the first EAM section (302) being preferably in anti-phase with the driving signal (312) at the second EAM section (304).
Abstract:
This writing discloses high-speed, single-drive and dual-drive external optical modulation devices that reduce the voltage and power required to amplify and modulate electrical signals onto an optical carrier. Two primary components of an optical transmitter (200), namely, the modulator (202) and driver (204), are integrated, and preferably hybridly integrated, in a single package, thereby eliminating many of the cable connector interfaces that add loss, complexity and cost to the system. Further, integration frees the devices from the standardized impedance (i.e. 50 ohm) constraints that reduce performance, thereby enabling the design of optimized, low voltage, hybridly integrated modulation devices.
Abstract:
An improved high-speed external optical modulator (10), modulated by RF waves, which velocity matches the RF waves with the optical waves is disclosed. The apparatus includes a lithium niobate substrate (16) on which is formed an optical waveguide (18, 20), electrically floating electrodes (32, 33, 34), a low dielectric buffer layer (30) and electrodes carrying the modulated RF energy (22, 24). At least one floating electrode (32, 33, 34) may comprise a series of spaced electrode segments for enhanced performance at high frequencies.
Abstract:
A distributed traveling-wave Mach-Zehnder modulator driver having a plurality of modulation stages that operate cooperatively (in-phase) to provide a signal suitable for use in a 100 Gb/s optical fiber transmitter at power levels that are compatible with conventional semiconductor devices and conventional semiconductor processing is described.
Abstract:
The invention relates to an electro-optic Mach-Zehnder modulator, comprising a first and a second optical branch (11, 11', 12, 12'); a first alternating voltage electrode arrangement (112, 112') for applying an alternating voltage across the first optical branch (11, 11'); a second alternating voltage electrode arrangement (122, 122') for applying an alternating voltage across the second optical branch (12, 12'); a first control electrode arrangement (114, 114') separate from the first alternating voltage electrode arrangement (112, 112') and for supplying a DC voltage across the first optical branch (11, 11'); a second control electrode arrangement (124, 124') separate from the second alternating voltage electrode arrangement (122, 122') and for supplying a DC voltage across the second optical branch (12, 12'), wherein the first control electrode arrangement (114, 114') and/or the second control electrode arrangement (124, 124') comprises a first control electrode (115, 115', 125, 125') and a second control electrode (116, 116', 126, 126'). According to the invention, the length of the first control electrode (115, 115', 125, 125') is different from the length of the second control electrode (116, 116', 126, 126'). The invention also relates to a method for operating a Mach-Zehnder modulator.
Abstract:
A Mach-Zehnder optica! modulator with a series push-pull traveling wave electrode uses a balanced coplanar stripline with lateral ground planes (G1,G2). Two signal electrodes (13A,13B) extend along the center of the optical modulator adjacent and parallel to the optical waveguides (15A,15B) in a series push-pull configuration. The ground planes (G1, G2) run parallel to the signal electrodes (13A,13B), but are spaced laterally outward from the signal electrodes (13A,13B).