US 2014/0112625 A1 · RECEIVER OPTICAL ASSEMBLIES (ROAS) HAVING PHOTO-DETECTOR REMOTELY LOCATED FROM TRANSIMPEDANCE AMPLIFIER, AND RELATED COMPONENTS, CIRCUITS, AND METHODS

Abstract

Embodiments disclosed herein include receiver optical assemblies (ROAs) having a photo-detector remotely located from a differential transimpedance amplifier (TIA). Related components, circuits, and methods are also disclosed. By providing the photo-detector remotely located from a TIA, additional costs associated with design constraints of providing the photo-detector intimate with a TIA may be avoided, thereby reducing cost of the ROA. In this regard as a non-limiting example, the ROAs according to the embodiments disclosed herein allow shorter haul active optical cable applications for use in consumer applications from a cost standpoint with the added benefits of increased bandwidth and low noise performance of optical fiber. In this regard, the ROAs disclosed herein provide higher input impedance differential TIA circuits and transmission circuits inhibiting or reducing ringing effects and maintain a sufficiently low resistance-capacitance (RC) time constant for differential TIA circuit to allow for higher bandwidth operation of the ROA.

Claims37

Dependent claims

A receiver optical assembly (ROA), comprising:

a photo-detector disposed in an optical header packaging, the photo-detector configured to detect and convert input optical signals into output electrical signals;
a differential transimpedance amplifier (TIA) circuit disposed in an integrated circuit remotely located from the optical header packaging, the differential TIA circuit comprising a first differential input node and a second differential input node, and the differential TIA circuit having a TIA input impedance of at least 10 ohms to reduce a ringing effect over the first differential input node and the second differential input node;
and
a transmission circuit comprised of a first transmission line coupled to the first differential input node, and a second transmission line coupled to the second differential input node;
a first node of the photo-detector coupled to the first transmission line and a second node of the photo-detector coupled to the second transmission line to couple the photo-detector to the differential TIA circuit to amplify the output electrical signals received from the photo-detector.

2 more elements

A method of assembling a receiver optical assembly (ROA), comprising:

disposing a photo-detector in an optical header packaging on a printed circuit board (PCB), the photo-detector configured to detect and convert input optical signals into output electrical signals;
disposing a differential transimpedance amplifier (TIA) circuit provided in an integrated circuit on the PCB remotely located from the optical header packaging, the differential TIA circuit comprising:
a first TIA having a first differential input node and a first output node;
a second TIA having a second differential input node and a second output node;
and
an output differential TIA having a first differential input node coupled to the first output node of the first TIA, and a second differential input node coupled to the second output node of the second TIA, the differential TIA circuit configured to reject common noise amplified by the first TIA and the second TIA;
the differential TIA circuit having a TIA input impedance of at least 10 ohms to reduce a ringing effect over the first differential input node and the second differential input node;
and
disposing a transmission circuit in the PCB comprised of disposing a first transmission line as a first PCB trace in the PCB and a second transmission line as a second PCB trace in the PCB;
coupling the first differential input node of the first TIA to the first transmission line and coupling the second differential input node of the second TIA circuit to the second transmission line;
and
coupling a first node of the photo-detector to the first transmission line and coupling a second node of the photo-detector to the second transmission line to couple the photo-detector to the differential TIA circuit to amplify the output electrical signals received from the photo-detector.

9 more elements

Dependencies are inferred from the claim text.

Receiver optical assemblies (roas) having photo-detector remotely located from transimpedance amplifier, and related components, circuits, and methods

Life of this patent

Receiver optical assemblies (roas) having photo-detector remotely located from transimpedance amplifier, and related components, circuits, and methods

Life of this patent

Abstract

Claims37