Semiconductor laser module, laser unit and Raman amplifier

Abstract

A semiconductive laser module according to the present invention is configured with a semiconductive laser module having a semiconductive laser device, a cavity formed with at least one light feedback means included, and an optical fiber located at a front side of the cavity, wherein an optical filter for transmitting light of wavelength within a predetermined range is disposed in the cavity. The above-noted semiconductive laser module additionally has a combination of a collimator and a focusing lens for coupling emitted light from the semiconductive laser device with the optical fiber, and the optical filter is disposed between the collimator and the focusing lens. The optical filter has a dielectric multi-layered filter for transmitting a desired wavelength. A laser unit according to the present invention is configured with a plurality of semiconductive laser modules as noted above, and a polarization combiner for making a polarization combination of emitted light from the plurality of semiconductive laser modules. A Raman amplifier according to the present invention has a pumping light source configured with the semiconductive laser module or the laser unit.

Description

technical field [0001] The invention relates to a Raman amplifier used in optical communication, and a semiconductor laser module and a laser unit using the Raman amplifier as a pumping light source. Background technique [0002] In most current applications of optical fiber communication systems, rare earth doped fiber amplifiers are used. Specifically, an erbium-doped fiber amplifier (hereinafter referred to as "EDFA") with erbium doping is generally used. However, EDFAs have a practical gain wavelength bandwidth ranging from 1530nm to 1610nm only. In addition, EDFA, when applied to wavelength division multiplexed light, has wavelength dependence in gain to produce a difference in gain depending on the wavelength of signal light. [0003] Before DWDM (Dense Wavelength Division Multiplexing), Raman amplification attracted attention as an amplification system having a wider frequency band than EDFA. Raman amplification is an optical signal amplification method utilizing t...

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Problems solved by technology

[0004] Although Raman amplification has such a feature that the wavelength of the gain used for generation can be changed arbitrarily by changing the pump light wavelength, the gain (Raman gain) is small

In addition, since the gain used is shifted from the wavelength of the pump light to a longer wavelength by a predetermined wavelength (Raman shift), a change in the wavelength of the pump light provides a wavelength change for the generated gain, resulting in amplification of the signal light characteristics change

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