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Optical modulating device

A technology of light modulation device and light intensity modulator, which is applied in optics, optical fiber transmission, nonlinear optics, etc., and can solve the problem of large reflected light value, etc.

Inactive Publication Date: 2007-10-10
NIPPON TELEGRAPH & TELEPHONE CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the end faces of the bidirectional optical amplifiers 409, 415 are low-reflection by non-reflection coating, the power of the reflected light is amplified before and after the end face reflection, so the value of the reflected light is large, and the reflected light and the signal light are separated. interfere with noise

Method used

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Embodiment 1

[0045] The first embodiment of the present invention adopts a method of inserting optical isolators every other time into a transmissive optical modulation device including a semiconductor optical amplifier (SOA) connected in multiple stages, and at the same time, it is achieved by reducing the influence of reflected light. The result is an embodiment with stable amplification function and reduced cost. Before describing a specific configuration example of this embodiment, the principle will be explained.

[0046]

[0047] Fig. 7 is a diagram illustrating reflected light when multiple SOAs are connected in multiple stages. In this multi-stage connection structure, in order to make it function as an optical modulation device, although it is necessary to either use one of the SOA to be used as an optical intensity modulator or insert an external modulator, here, In order to simplify the description of reflected light, it is assumed that all SOAs only function as optical amplifiers....

Embodiment 2

[0061] 12A-12C are diagrams illustrating the structure of the light modulation device according to the second embodiment of the present invention. This embodiment corresponds to a modification of the first embodiment, and is applied to the three SOA S constituting the optical amplifier 1 , S 2 , S 3 A light intensity modulator M is inserted between any of them.

[0062] Figure 12A is the optical isolator O 1 , O 2 The light intensity modulator M is inserted in the section of. Here, although it is shown to the first and second SOA S 1 , S 2 2nd optical path (optical connection device) between x 2 The example where the light intensity modulator M is inserted, but it can also be added to the 3rd SOA S 3 4th optical path between output terminal and x 4 Insert the light intensity modulator M inside. However, in this case, it is necessary to use SOA S that can handle the last level 3 A light intensity modulator M with amplified light power.

[0063] In the structure of Figure 12A, from ...

Embodiment 3

[0067] The optical modulation device of the third embodiment of the present invention is made such that in the device configuration having the bidirectional optical amplifier shown in FIG. 4, the numerical limitation of the gain of the amplifier can be adopted as described later, thereby reducing A device that realizes a stable amplification function under the influence of the reflected light on the end face of the bidirectional optical amplifier. Hereinafter, the numerical limitation of the amplifier gain of the present invention will be described.

[0068]

[0069] As shown in FIG. 4, there are two reflected lights from both ends of the bidirectional optical amplifiers 409 and 415, one reflected light 1 and modulated light, and the other reflected light 2 travels in the same direction as the continuous light. The continuous light becomes modulated light due to intensity modulation. Since the reflected light 2 has to go through the same path as the continuous light, the reflecte...

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Abstract

An optical modulation apparatus is provided which implements a stable amplifying function by reducing the effect of reflected light rays form end faces of a bidirectional optical amplifier by imposing a numerical limitation on the relationship between the gain of the bidirectional optical amplifier and the loss of the optical modulator, or by inserting a polarization rotation section in a reflection type optical modulator including the bidirectional optical amplifier or in a multi-wavelength collective optical modulation system combining the multiple optical modulators. An optical modulation apparatus is provided which implements a stable amplifying function and cost reduction by reducing the effect of reflected light rays by interposing optical isolators at every alternate SOAs in a transmission-type optical modulation apparatus including a plurality of semiconductor optical amplifiers (SOAs) connected in a multistage fashion.

Description

Technical field [0001] The present invention relates to an optical modulation device used for optical communication, and more particularly, to a construction technology of an optical modulation device constructed by combining an optical amplifier such as a semiconductor optical amplifier and an optical intensity modulator. Background technique [0002] In the past, people have been studying ways to use multi-wavelength light including multiple optical carriers generated by optical short-pulse lasers or amplitude / phase modulation to transmit WDM (Wavelength Division Multiplexing) signals. The spectral intervals of each side mode of such multi-wavelength light are all equal, and the channels obtained by performing wavelength separation on the side modes become equal wavelength intervals. Therefore, in terms of wavelength configuration, such multi-wavelength light is more convenient than multi-wavelength light generated by preparing a separate laser for each channel and setting the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02F1/01H04B10/2587H04B10/297H04B10/516H04J14/02
Inventor 藤原正满可儿淳一秋本浩司岩月胜美
Owner NIPPON TELEGRAPH & TELEPHONE CORP
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