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Prediction of Channel Calibration Correction versus Gain Medium Current

IP.com Disclosure Number: IPCOM000010807D
Publication Date: 2003-Jan-22
Document File: 3 page(s) / 129K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that predicts the correction value for the ideal calibration position of a tunable laser as a function of gain medium current. Benefits include using only one channel calibration procedure at a single gain medium current level.

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Prediction of Channel Calibration Correction versus Gain Medium Current

Disclosed is a method that predicts the correction value for the ideal calibration position of a tunable laser as a function of gain medium current. Benefits include using only one channel calibration procedure at a single gain medium current level.

Background

Currently, a power controlled tunable laser without an external optical attenuator requires that the gain medium current be set to a corresponding range. Depending on the characteristics of the gain medium, this range introduces channel instability and frequency drift if the channel position is not compensated accordingly. Without a correction factor, calibration of the laser for each operating current increases the calibration time by an order of n.

General Description

The disclosed method predicts the correction factor in the channel calibration as a function of the gain medium current for tunable lasers that operate by suppressing adjacent “super channels”. The disclosed method attempts to operate at the tuning transmission peak in order to provide the  maximum and the most stable output power; internal feedback from any simple power detection scheme is used to track to this peak power. But in tunable lasers, this does not always provide the best Side-Mode Suppression Ratio (SMSR) or frequency stability. The center point between the channel boundaries in the tuning map provides the best SMSR and the most protection from erroneously transmitting at another frequency-channel. Therefore, at low gain medium current, the power and SMSR channel center line up, while at high gain medium current they do...