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Optical modulating device

A technology of a light modulation device and a modulation part, which is applied in optics, optical fiber transmission, nonlinear optics, etc., and can solve the problems of large reflected light value and the like

Inactive Publication Date: 2005-12-07
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] Embodiment 1 of the present invention adopts the method of inserting every other optical isolator to the transmissive optical modulation device including the semiconductor optical amplifier (SOA) connected in multiple stages, and simultaneously realizes reducing the influence of reflected light And the obtained stable amplification function and the reduced embodiment of cost. Before describing a specific configuration example of this embodiment, its principle will be described.

[0046]

[0047] Figure 7 It is a figure explaining the reflected light at the time of multistage connection of several SOA. In this multi-stage connection configuration, in order to make it function as an optical modulator, it is necessary to either use one of the SOAs to be used as an optical intensity modulator, or to insert an external modulator, but here, In order to simplify the description of reflected light, it is assumed that all SOAs function only as optical amplifiers.

[0048] ...

Embodiment 2

[0061] Figures 12A-12C It is a figure explaining the structure of the light modulation apparatus of Example 2 of this invention. This embodiment is equivalent to a modified example of Embodiment 1, and the three SOAs constituting the optical amplifier 1 , S 2 , S 3 A light intensity modulator M is inserted between any one of them.

[0062] Figure 12A is not inserted into the optoisolator O 1 , O 2 The composition of the light intensity modulator M is inserted in the interval of . Here, although it is shown that the 1st and 2nd SOAs 1 , S 2 The second optical path between (optical connection device) x 2 Inserted within the example of an optical intensity modulator M, however, it is also possible to add a 3rd SOA S 3 4th optical path between output terminal x 4 A light intensity modulator M is inserted. However, in this case, it is necessary to use SOAS that can cope with the last level 3 The amplified optical power is carried out by the optical intensity modulato...

Embodiment 3

[0067] The light modulation device of Embodiment 3 of the present invention is made such that after having the above-mentioned Figure 4 In the device configuration of the bidirectional optical amplifier as shown, the method of limiting the gain of the amplifier as described later can be used to reduce the influence of reflected light on the end face of the bidirectional optical amplifier and realize a stable amplification function. Next, the numerical limitation of the amplifier gain of the present invention will be described.

[0068]

[0069] Such as Figure 4 As shown, 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 and continuous light travel in the same direction. The continuous light becomes modulated light by intensity modulation, and the reflected light 2 follows the same path as the continuous light, so reflected light 1 and reflected light ...

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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 in optical communication, and in particular to a construction technique of an optical modulation device composed of a combination of an optical amplifier such as a semiconductor optical amplifier and an optical intensity modulator. Background technique [0002] In the past, people have been studying the method of using multi-wavelength light including multiple optical carriers generated by optical short-pulse laser or amplitude modulation / phase modulation for wavelength division multiplexing (WDM, Wavelength Division Multiplexing) signal transmission. The spectral intervals of side modes of such multi-wavelength light are all equal, and the channels obtained by wavelength-separating the side modes have equal wavelength intervals. Therefore, such multi-wavelength light is also simpler in terms of wavelength arrangement than multi-wavelength light generated by preparing separate laser bea...

Claims

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Application Information

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Patent Type & Authority Applications(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