Method for keeping mode locking state of Fabri-Pero laser and light source thereof

Abstract

A method for maintaining the mode-locked state of a Fabry-Perot (FP) laser and a WDM light source using the same method for use in WDM optical communication are disclosed. The mode-locked state can be maintained irrespective of temperature change, without use of a temperature controller, by spectrum-slicing the incoherent light generated by a light source element and injecting the spectrum-sliced light to the FP laser, then the FP laser amplifies and outputs only a lasing mode coinciding with the wavelength of the injected light, wherein a lasing-mode interval of the FP laser is set to be less than a 3 dB linewidth of the injected light, so that at least one lasing mode exists inside the 3 dB linewidth of the injected light irrespective of changes in external temperature.

Description

technical field [0001] The present invention relates to wavelength division multiplexing (WDM) optical communication, and in particular to a method for maintaining the mode-locked state of a Fabry-Perot laser regardless of ambient temperature variations and a WDM incorporating this method light source. Background technique [0002] WDM passive optical networks (PONs) typically provide high-speed, broadband communication services using a unique wavelength assigned to each user. Likewise, WDM-PON can guarantee the confidentiality of communication. In addition, it can accommodate communication capacity expansion requested by each user, and easily expand the number of users only by increasing unique wavelengths allocated to new users. Regardless of these advantages, WDM-PON has not been put into practical use because it imposes a heavy economic burden on users due to the need to provide a central office (CO) and each user with a specific light source for generating laser or os...

AI Technical Summary

Problems solved by technology

However, LEDs and SLDs are suitable as light sources for uplink signals with lower modulation rates rather than downlink signals due to their low modulation bandwidth and low output power

The FP laser is a low-price, high-output unit, but its disadvantages are: it cannot provide a large number of WDM channels because of its small bandwidth, and when modulating and transmitting spectrally sliced ​​signals at high speeds due to severe mode allocation noise, its reduced performance

[0009] However, conventional FP lasers add to the packaging expense because the thermistor and TEC must be connected to the FP laser, and an additional TEC controller needs to be provided, further increasing the overall cost

These add a high economic burden to users, so WDM-PON has not been widely accepted

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