Electro-optical communications link
AssigneeTeradyne, Inc.
InventorMarlon Zbigniew Kasprzyk
Life of this patent
Estimating the term…
Abstract
A communications link for carrying data between a transmitter and a receiver operates according to a communications protocol (such as PCI Express (PCIe)) specifying a reduced-power link operating state in which the transmitter generates a reduced-amplitude electrical output signal and the receiver is to operate in a power-save mode. The communications link includes an electro-optical link and a circuit coupling an output of the transmitter to an electrical input of the electro-optical link. The circuit is configured to detect initiation of the reduced-power operating state and to send messages to the receiver to maintain a normal amplitude of an optical signal on the electro-optical link.
Claims18
A communications link for carrying data between a transmitter and a receiver according to a communications protocol specifying a reduced-power link operating state in which the transmitter generates a reduced-amplitude electrical output signal at an electrical output and the receiver is to operate in a power-save mode, the communications link comprising:
- an electro-optical link having an E/O converter for generating an optical signal from an electrical input signal at an electrical input, an optical transmission medium for carrying the optical signal, and an O/E converter for generating an electrical output signal from the optical signal, the electrical output signal provided to the receiver;
- and
- a circuit coupling the electrical output of the transmitter to the electrical input of the electro-optical link, the circuit being configured to (1) forward the electrical output signal of the transmitter to the electrical input of the electro-optical link during normal-power link operation, and (2) detect initiation of the reduced-power link operating state and, during the reduced-power link operating state, to periodically send Idle messages to the receiver via the electro-optical link to maintain a normal amplitude of the optical signal on the electro-optical link causing the receiver to maintain normal-power operation during the reduced-power link operating state.
A computer system, comprising:
- a host controller;
- a peripheral device;
- and
- a communications link connecting the host controller as a transmitter to the peripheral device as a receiver, the communications link operating according to a communications protocol specifying a reduced-power link operating state in which the transmitter generates a reduced-amplitude electrical output signal at an electrical output and the receiver is to operate in a power-save mode, the communications link including:
- an electro-optical link having an E/O converter for generating an optical signal from an electrical input signal at an electrical input, an optical transmission medium for carrying the optical signal, and an O/E converter for generating an electrical output signal from the optical signal, the electrical output signal provided to the receiver;
- and
- a circuit coupling the electrical output of the transmitter to the electrical input of the electro-optical link, the circuit being configured to (1) forward the electrical output signal of the transmitter to the electrical input of the electro-optical link during normal-power link operation, and (2) detect initiation of the reduced-power link operating state and, during the reduced-power operating link state, to periodically send Idle messages to the receiver via the electro-optical link to maintain a normal amplitude of the optical signal on the electro-optical link causing the receiver to maintain normal-power operation during the reduced-power link operating state.
A communications link for carrying data between a transmitter and a receiver according to a communications protocol specifying a reduced-power link operating state in which the transmitter generates a reduced-amplitude electrical output signal at an electrical output and the receiver is to operate in a power-save mode, the communications link comprising:
- an electro-optical link having an E/O converter for generating an optical signal from an electrical input signal at an electrical input, an optical transmission medium for carrying the optical signal, and an O/E converter for generating an electrical output signal from the optical signal, the electrical output signal provided to the receiver;
- and
- a circuit coupling the electrical output of the transmitter to the electrical input of the electro-optical link, the circuit being configured to (1) forward the electrical output signal of the transmitter to the electrical input of the electro-optical link during normal-power link operation, and (2) detect initiation of the reduced-power link operating state and to send messages to the receiver via the electro-optical link to maintain a normal amplitude of the optical signal on the electro-optical link,
- wherein the electro-optical link includes a transmit optical subassembly housing the E/O converter, and a receiver optical subassembly housing the O/E converter, the transmit optical subassembly being operative to generate the optical signal on the optical transmission medium having a level corresponding to a level of the electrical input signal, and the receiver optical subassembly including a variable-gain circuit having a gain-adjustment delay capable of causing transitory saturation resulting in the inaccurate reproduction of a transmitted message, the gain-adjustment delay being prevented by the maintaining of the normal amplitude of the optical signal on the electro-optical link during the reduced-power link operating state.
A computer system, comprising:
- a host controller;
- a peripheral device;
- and
- a communications link connecting the host controller as a transmitter to the peripheral device as a receiver, the communications link operating according to a communications protocol specifying a reduced-power link operating state in which the transmitter generates a reduced-amplitude electrical output signal at an electrical output and the receiver is to operate in a power-save mode, the communications link including:
- an electro-optical link having an E/O converter for generating an optical signal from an electrical input signal at an electrical input, an optical transmission medium for carrying the optical signal, and an O/E converter for generating an electrical output signal from the optical signal, the electrical output signal provided to the receiver;
- and
- a circuit coupling the electrical output of the transmitter to the electrical input of the electro-optical link, the circuit being configured to (1) forward the electrical output signal of the transmitter to the electrical input of the electro-optical link during normal-power link operation, and (2) detect initiation of the reduced-power link operating state and to send messages to the receiver via the electro-optical link to maintain a normal amplitude of the optical signal on the electro-optical link,
- wherein the electro-optical link includes a transmit optical subassembly housing the E/O converter, and a receiver optical subassembly housing the O/E converter, the transmit optical subassembly being operative to generate the optical signal on the optical transmission medium having a level corresponding to a level of the electrical input signal, and the receiver optical subassembly including a variable-gain circuit having a gain-adjustment delay capable of causing transitory saturation resulting in the inaccurate reproduction of a transmitted message, the gain-adjustment delay being prevented by the maintaining of the normal amplitude of the optical signal on the electro-optical link during the reduced-power link operating state.
Dependencies are inferred from the claim text.