Systems for deploying an optical network

Abstract

A transmitter on an integrated circuit chip is disclosed that employs a laser, modulator, and a dispersion compensator module and a modulator for overcoming chromatic dispersion and polarization dependent loss effects. With the present invention, the dispersion compensator module is placed on a chip, either integrated or monolithic, for operation with a laser and a modulator without the need to compensate for dispersion within a separate unit that is not part of the chip. The dispersion compensator module can be implemented, for example, with a ring resonator, an etalon or a Mach-Zehnder interferometer. In a first aspect of the invention, the optical transmitter module of the present invention provides a cost-effective solution for upgrading from an existing optical network to a faster optical network, such as upgrading from a 2.5 Gbps to a 10 Gbps network. In a second aspect of the invention, the optical transmitter module of the present invention provides a means to deploy an optical network at the transmission rate of 10 Gbps, 40 Gbps and faster.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional of co-pending U.S. patent application Ser. No. 11 / 098,837, filed Apr. 4, 2005, which is herein incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates generally to the field of fiber optic networks and systems and more particularly to dispersion compensation in optical and photonic networks.[0004]2. Description of the Related Art[0005]The evolution of optical technologies intersecting with the industrial drive to utilize material science in designing an integrated circuit chip as a compact and cost-effective solution creates a platform for an innovative approach in addressing properties associated with optics and electronics. Traditional optical theories provide an understanding to make a purely optical-based device but the resulting product is frequently bulky in size, while electronic theories push relentlessly for a greater integration and miniatur...

AI Technical Summary

Benefits of technology

[0011]In a first aspect of the invention, the optical transmitter module of the present invention provides a cost-effective solution for upgrading from an existing optical network to a faster optical network, such as upgrading from a 2.5 Gbps to a 10 Gbps network. In a second aspect of the invention, the optical transmitter module of the present invention provides a means to deploy an optical network at the transmission rate of 10 Gbps, 40 Gbps and faster.

[0012]A first preferred embodiment of an optical transmitter module in accordance with the present invention comprises a laser coupled to a modulator through a dispersion compensator module where the dispersion compensator module is designed so as to have an angle associated with a single polarized light that will either minimize the polarization dependent loss, or keep the polarization dependent loss unchanged or substantially the same. A second preferred embodiment of an optical transmitter module in accordance with the present invention comprises a laser coupled to a modulator that is further coupled to a dispersion compensator module wherein a polarization maintaining fiber is placed on either side of the modulator for maintaining the polarization of the single polarized light. Each of the transmitter embodiments can be designed as a stand-alone transmitter, as a component in a transceiver, or as a component in a transponder.

[0013]Advantageously, the present invention facilitates a simpler apparatus and method for upgrading an existing optical network at a central office by swapping, for example, a 2.5 Gbps line card with a 10 Gbps line card without the cumbersome and costly need, for instance, to install new dispersion compensating fiber within a fiber optic transmission system.

Problems solved by technology

Traditional optical theories provide an understanding to make a purely optical-based device but the resulting product is frequently bulky in size, while electronic theories push relentlessly for a greater integration and miniaturization of integrated circuits by following the so-called Moore's Law.

A common well-known problem in high-speed transmission of optical signals is chromatic dispersion.

This particular problem becomes more acute for data transmission speeds higher than 2.5 gigabits per second (Gbps).

The resulting pulses of the signal will be stretched, will possibly overlap, and will cause increased difficulty for optical receivers to distinguish where one pulse begins and another ends.

This effect seriously compromises the integrity of a signal.

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