Abstract:
A modular optical device having a set of optoelectronic modules that enables the device to operate, e.g., as a WDM or multichannel transceiver. In an example embodiment, the set of optoelectronic modules includes a laser module, a modulator module, and an optical-to-electrical converter module, all mounted on the same circuit board and optically and electrically connected for the intended application. Each of the optoelectronic modules comprises a respective stack of integrated circuits, at least one of which is a photonic integrated circuit (PIC). Some of the PICs may be configurable for different applications, with the configuration setup being carried out using electrical control signals and/or optical connections of the PICs. The modular structure of the device enables the manufacturer to provide customized solutions to different customers according to their respective specifications while using the same device architecture and/or to interchangeably use parts obtained from different suppliers to engineer those solutions.
Abstract:
The present invention relates to a multi-channel IM-DD optical transceiver comprising at least one transmitter and a receiver, and a method for equalizing input samples at an adjusted sampling phase using a quality parameter linearly proportional to a BER. The data transmission and reception use a single master channel and slave channels, which have a baud rate equal to or lower than the baud rate of the master channel. A reliable and identical clocking of all the channels is obtained through either the receiver clock of the master channel when they are received from a single transmitter or a reference clock whose frequency is higher than the highest clock frequency amongst all the channels when they are received from a combination of transmitters. An enhanced timing recovery circuit is also provided to select optimized finite impulse response filters, calculate filter coefficients and generate the receiver clock of the master channel. Each channel of the receiver comprises a timing recovery circuit adapted to control a sampling phase of an interpolator.
Abstract:
A pseudo-random cipher stream is used to band-spread an optical carrier signal with coded data. A legitimate receiver uses an agreed-upon key to modulate its local oscillator and a resulting beat signal uncovers the band-spread signal. An eavesdropper who does not have the key finds the spread signal with too low signal-to-noise ratio to perform any useful determination of the message sequence. Theoretical bounds based on Shannon's Theory of Secrecy are used to show strength of the encoding scheme and predict it to be superior to the prior art.
Abstract:
Traditional satellite-to-earth data transmission systems are constrained by inefficient relay schemes and/or short-duration data transfers at low data rates. Communication systems described herein achieve extremely high burst rate (e.g., 10 Gbps or greater) direct-to-Earth (DTE) data transmission over a free-space optical link between a spacecraft and a remote terminal, which may be a ground terminal or another space terminal. The optical link is established, for example, when the remote terminal is at an elevation of 20〬 with respect to a horizon of the remote terminal. In some embodiments, a data transmission burst contains at least 1 Terabyte of information, and has a duration of 6 minutes or less. The communication system can include forward error correction by detecting a degradation of a received free-space optical signal and re-transmitting at least a portion of the free-space optical signal.
Abstract:
Traditional satellite-to-earth data transmission systems are constrained by inefficient relay schemes and/or short-duration data transfers at low data rates. Communication systems described herein achieve extremely high burst rate (e.g., 10 Gbps or greater) direct-to-Earth (DTE) data transmission over a free-space optical link between a spacecraft and a remote terminal, which may be a ground terminal or another space terminal. The optical link is established, for example, when the remote terminal is at an elevation of 20〬 with respect to a horizon of the remote terminal. In some embodiments, a data transmission burst contains at least 1 Terabyte of information, and has a duration of 6 minutes or less. The communication system can include forward error correction by detecting a degradation of a received free-space optical signal and re-transmitting at least a portion of the free-space optical signal.
Abstract:
Disclosed herein is a dual parallel Mach-Zehnder-modulator (DPMZM) device comprising a DPMZM 10 having first and second inner MZMs arranged parallel to each other. The first inner MZM generates an in-phase component E I of an optical signal in response to a first driving voltage V I , and the second inner MZM generates a quadrature component E Q of said optical signal in response to a second driving voltage V Q . Further disclosed is a calculation unit 52 configured for receiving an in-phase component y I and a quadrature component y Q _ of a desired base-band signal, and for calculating pre-distorted first and second driving voltages V I , V Q . The calculation of the pre-distorted first and second driving voltages V I , V Q is based on a model of said DPMZM 10 accounting for I-Q cross-talk, and using an algorithm that determines said first and second driving voltages V I , V Q each as a function of both of said in- phase and quadrature components y I , y Q of said base-band signal.