JP5566966B2 - Semiconductor optical device - Google Patents

Description

  The present invention relates to an integrated semiconductor optical device integrated on a semiconductor substrate.

  Various laser light sources such as semiconductor lasers are known. As a laser light source for a large-capacity optical transmission device, a laser light source having a high output and a narrow linewidth spectrum is required.

Also known are optical components such as a semiconductor laser element, an optical combiner that combines and outputs a plurality of laser beams, and a semiconductor optical amplifier. A semiconductor optical device in which these optical components are integrated on one semiconductor substrate is known.
[Patent Literature]
Patent Document 1 Japanese Patent Application Laid-Open No. 2005-317695 [Non-patent Document]
Non-Patent Document 1 Geert Mortier, “Intensity Noise And Linewidth Of Laser Diodes With Integrated Semiconductor Optical Amplifier E.L. 14, no. 12, P.I. 1644-1646

  However, when the laser light emitted from the optical combiner is amplified by the semiconductor optical amplifier and output from the semiconductor optical element, a part of the spontaneous emission light emitted from the semiconductor optical amplifier enters the semiconductor laser element. . When spontaneous emission light or the like is input to the semiconductor laser element, a phenomenon has occurred in which the line width of the laser light spectrum output from the semiconductor laser element is widened (Non-Patent Document 1).

  According to the first aspect of the present invention, a plurality of laser elements, an optical combiner that is connected to each of the plurality of laser elements via a waveguide, and combines laser beams output from the plurality of laser elements, A semiconductor optical amplifier that amplifies the laser light output from the optical device, and the optical combiner and the semiconductor optical amplifier on the same substrate, respectively, on a path between each of the laser elements and the optical combiner. A semiconductor optical device comprising a plurality of wavelength selective filters is provided.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

It is the top view which looked at the semiconductor optical element concerning the 1st Embodiment of this invention from the upper surface. It is a block diagram for demonstrating the method to control the output light wavelength of the semiconductor optical element concerning 1st Embodiment. It is the top view which looked at the semiconductor optical element concerning the 2nd Embodiment of this invention from the upper surface. It is a block diagram for demonstrating the method to control the output light wavelength of the semiconductor optical element concerning 2nd Embodiment. It is the top view which looked at the semiconductor optical element concerning the modification of 2nd Embodiment from the upper surface.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a plan view of a semiconductor optical device according to the first embodiment of the present invention as viewed from above. The semiconductor optical device 10 includes a substrate 100, a plurality of laser devices 110, a plurality of wavelength selection filters 120, an optical combiner 130, and a semiconductor optical amplifier 140. The semiconductor optical device 10 outputs light emitted from a selected one of the plurality of laser devices 110 from the end of the semiconductor optical amplifier 140.

  The substrate 100 is a semiconductor substrate or the like on which a plurality of laser elements 110, a plurality of wavelength selection filters 120, an optical combiner 130, and a semiconductor optical amplifier 140 are formed.

  Each of the plurality of laser elements 110 outputs laser beams having different wavelengths. The laser element 110 is a semiconductor laser element formed on the substrate 100 in the first embodiment. For example, the laser element 110 is a distributed feedback laser element or a distributed reflection laser element. Since the refractive index of the laser element 110 varies depending on the temperature, the oscillation wavelength of the output laser can be controlled by the ambient temperature. Each semiconductor laser element 110 can be a wavelength tunable light source whose oscillation wavelength changes within a range of 3 nm to 4 nm by changing the ambient temperature.

  For example, by arranging four semiconductor laser elements 110 having different oscillation bands so that the oscillation wavelengths are continuously arranged at intervals of 3 nm to 4 nm, the semiconductor optical element 10 has a variable wavelength band of the output laser light of 12 nm. It can be ˜16 nm. Such a semiconductor optical device 10 can emit laser light in a continuous wavelength band in a wider band than when a single semiconductor laser device is used when compared in the same control temperature range.

  The wavelength selection filter 120 is formed on the same substrate 100 as the optical combiner 130 and the semiconductor optical amplifier 140, and allows light in a predetermined pass wavelength band to pass therethrough. The wavelength selection filter 120 is formed on a path between each of the plurality of laser elements 110 and the optical combiner 130, and selectively allows the wavelength of the laser light output from the corresponding laser element 110 to pass therethrough. On the other hand, each of the plurality of wavelength selection filters 120 attenuates light other than the wavelength of the laser light output from the corresponding laser element 110. Each of the plurality of wavelength selection filters 120 can change the pass wavelength band.

  The wavelength selection filter 120 is a ring filter formed on the substrate 100. Therefore, the wavelength selection filter 120 can be formed on the substrate 100 by a semiconductor process. Alternatively, the wavelength selection filter 120 may be a bandpass filter other than a ring filter such as a multilayer filter or an etalon filter.

  The ring filter has an input waveguide, a ring waveguide, and an output waveguide. The input waveguide and the ring waveguide are optically coupled, and the ring waveguide and the output waveguide are optically coupled. The input waveguide is connected to the input end of the ring filter, and the output waveguide is connected to the output end of the ring filter. The output waveguide and the output end of the ring filter are offset from the input waveguide and the input end of the ring filter by the diameter of the ring waveguide in a direction (+ x direction) perpendicular to the optical axis on the substrate 100.

The ring filter has a plurality of pass wavelength bands. Specifically, a relational expression of λ _n = l / n (n is an integer) is established between the optical path length l of the ring waveguide of the ring filter and the center wavelength λ _n of the pass wavelength band of the ring filter. Λ _n satisfying this relational expression appears periodically at constant wavelength intervals as n increases or decreases. The ring filter has a shielding wavelength band that shields light between the passing wavelength bands. Accordingly, in the wavelength / transmittance characteristics of the ring filter, a pass wavelength band that transmits most light and a cut-off wavelength band that blocks most light alternately appear at regular wavelength intervals.

  The wavelength selection filter 120 may be a ring filter provided with a micro heater 150. The micro heater 150 adjusts the pass wavelength band of the wavelength selection filter 120 by adjusting the temperature of the wavelength selection filter 120. For example, the semiconductor optical device 10 heats the ring filter by the microheater 150, thereby extending the optical path length of the ring waveguide and changing the pass wavelength band of the ring filter in the long wavelength direction.

The microheater 150 controls the optical path length l of the ring waveguide so that the wavelength of the output laser of the corresponding laser element 110 and the pass wavelength band λ _n are substantially equal. The wavelength selection filter 120 may have a wavelength adjustment terminal on the surface of the substrate 100 for the purpose of controlling the current supplied to the micro heater 150.

  The pass wavelength band of the wavelength selection filter 120 includes the entire variable wavelength band of the corresponding laser element 110. The semiconductor optical device 10 may initially adjust the current supplied to each microheater 150 so that the pass wavelength band of the wavelength selection filter 120 includes the entire variable wavelength band of the corresponding laser element 110. After the initial adjustment, the semiconductor optical device 10 may not control the pass wavelength band of the wavelength selection filter 120.

  Instead, the pass wavelength band of the wavelength selection filter 120 may be smaller than the variable wavelength band of the corresponding laser element 110. In this case, the pass wavelength band of the wavelength selection filter 120 is controlled so as to include the wavelength of the output laser light of the corresponding laser element 110.

  The optical combiner 130 is formed on the substrate 100 and is connected to each of the plurality of laser elements 110 via a waveguide. The optical combiner 130 combines the laser beams output from the plurality of laser elements 110. The optical combiner 130 may be a multimode interference (MMI) optical coupler that can be formed by a semiconductor process.

  The semiconductor optical amplifier 140 is formed on the substrate 100, is connected to the optical combiner 130, and amplifies the laser light output from the optical combiner 130. The semiconductor optical amplifier 140 forms an inversion distribution by injecting current from the outside, and amplifies input light by stimulated emission.

  Next, the operation of the semiconductor optical device 10 in the first embodiment will be described. First, the semiconductor optical device 10 selects a laser device 110 that outputs laser light having a wavelength to be output, and drives the laser device 110. The selected laser element 110 emits laser light toward the wavelength selection filter 120. The wavelength selection filter 120 selectively passes the laser light output from the corresponding laser element 110 and attenuates light of other wavelengths.

  Therefore, the laser light passing through the wavelength selection filter 120 is output to the optical combiner 130 with almost no attenuation. The laser light incident on the optical combiner 130 passes through the optical combiner 130 and is output to the semiconductor optical amplifier 140. The laser light incident on the semiconductor optical amplifier 140 is amplified by the semiconductor optical amplifier 140 and is output to the outside from the output end provided at the end of the semiconductor optical device 10.

  Here, the semiconductor optical amplifier 140 generates spontaneous emission light having a band of several tens of nm in addition to stimulated emission light that is amplified light emitted to the output end of the semiconductor optical device 10. Since the spontaneous emission light of the semiconductor optical amplifier 140 is emitted substantially isotropically, it is also output in the direction of the optical combiner 130. The spontaneous emission light input to the optical combiner 130 is branched by the optical combiner 130 and travels to each laser element 110. When the spontaneous emission light reaches the laser element 110, the output of the laser element 110 becomes unstable, and the line width of the wavelength spectrum of the output laser light increases.

  On the other hand, according to the semiconductor optical device 10 according to the first embodiment, the spontaneous emission light enters the wavelength selection filter 120 before reaching the laser device 110. Here, each of the plurality of wavelength selection filters 120 attenuates spontaneous emission light in a cutoff wavelength band other than the wavelength of the laser light output from the laser element 110. For this reason, the wavelength selection filter 120 can attenuate the spontaneous emission light toward the laser element 110 and reduce the optical power incident on the laser element 110.

  As described above, the semiconductor optical device 10 according to the first embodiment attenuates spontaneous emission light incident on the laser device 110 by the ring filter. For this reason, the semiconductor optical device 10 according to the first embodiment can reduce the influence of spontaneous emission light and output a laser beam having a narrow linewidth spectrum.

  The semiconductor optical device 10 may include a single laser element 110 instead of the plurality of laser elements 110. In the case of having a single laser element, the semiconductor optical element 10 may not include an optical combiner. In this case, the semiconductor optical element includes a single laser element 110, a semiconductor optical amplifier 140, and a wavelength selection filter 120 formed on a path between the laser element 110 and the semiconductor optical amplifier 140.

  FIG. 2 is a block diagram for explaining a method of controlling the wavelength of output light of the semiconductor optical device according to the first embodiment. In the example of FIG. 2, the control unit 160 is used to control the output light wavelength of the semiconductor optical device.

  The control unit 160 is electrically connected to the plurality of laser elements 110 and the plurality of micro heaters 150, respectively. The control unit 160 supplies a drive current to the laser element 110 to cause the laser element 110 to output laser light. The controller 160 controls the temperature of the microheater 150 by controlling the current supplied to the microheater 150. The controller 160 adjusts the pass wavelength band of the wavelength selection filter 120 corresponding to the microheater 150 by controlling the temperature of the microheater 150. The control unit 160 may control the microheater 150 through a wavelength adjustment terminal on the substrate 100.

  The control unit 160 selects the laser element 110 to be used for the output of the semiconductor optical element 10 by supplying a drive current to a selected one of the plurality of laser elements 110. In this case, the control unit 160 controls the micro heater 150 of the wavelength selection filter 120 connected to the selected laser element 110 to output the laser light output from the laser element 110 from the semiconductor optical element 10. According to this control method, since no drive current is supplied to the laser element 110 and the corresponding microheater 150 that have not been selected, the power consumption of the semiconductor optical element 10 can be reduced.

  Instead of this, the control unit 160 may output laser light to all of the plurality of laser elements 110 and control the plurality of wavelength selection filters 120 to select the laser light used for output. In this case, first, the control unit 160 selects the wavelength selection filter 120 connected to the laser element 110 to be output. Then, the microheater 150 is controlled so that the selected wavelength selection filter 120 passes the laser beam of the corresponding laser element 110.

  At the same time, the control unit 160 controls each of the micro heaters 150 so that the wavelength selection filters 120 that are not selected do not pass the laser light of the corresponding laser element 110. According to this control method, each laser element is always kept on, so that a stable optical output can be output from the semiconductor optical element 10.

  As described above, according to the method of controlling the semiconductor optical device 10 described with reference to FIG. 2, the semiconductor optical device 10 causes the control unit 160 to output laser light having a wavelength to be output from the plurality of laser devices 110. And the laser beam can be output. Further, the semiconductor optical device 10 can reduce the spontaneous emission light incident on the laser device 110 while passing the laser beam output from the selected laser device by using the wavelength selection filter 120.

  FIG. 3 is a plan view of a semiconductor optical device according to the second embodiment of the present invention as viewed from above. The semiconductor optical device 20 includes a substrate 100, a plurality of laser devices 110, an optical combiner 130, a semiconductor optical amplifier 140, and a wavelength selection filter 224. The semiconductor optical device 20 outputs light emitted from a selected one of the plurality of laser devices 110 from the end of the semiconductor optical amplifier 140.

  In the second embodiment, the substrate 100, the plurality of laser elements 110, the optical combiner 130, and the semiconductor optical amplifier 140 have substantially the same configuration as that of the first embodiment, and thus the description thereof is omitted.

  The wavelength selection filter 224 passes light in a part of the wavelength band. The wavelength selection filter 224 is formed on a path between the optical combiner 130 and the semiconductor optical amplifier 140. The wavelength selection filter 224 is formed on the same substrate 100 as the semiconductor optical amplifier 140.

  The wavelength selection filter 224 may be a variable wavelength selection filter that selectively transmits the wavelength of the laser light from the laser element 110 selected from among the plurality of laser elements 110. The wavelength selection filter 224 attenuates light other than the wavelength of the laser light output from the selected laser element.

  The wavelength selection filter 224 includes a first ring filter 220 and a second ring filter 222 connected in series. The wavelength selection filter 224 adjusts the pass wavelength band and the shielding wavelength band by changing the pass wavelength bands of the first ring filter 220 and the second ring filter 222, respectively. The wavelength selection filter 224 may include three or more ring filters connected in series.

  The first ring filter 220 and the second ring filter 222 are the same ring filters as those described in the first embodiment. The first ring filter 220 may be a ring filter provided with the first micro heater 250. Further, the second ring filter 222 may be a ring filter provided with a second micro heater 252. In order to control the current of the first microheater 250 and the second microheater 252, the first ring filter and the second ring filter may each have a wavelength adjustment terminal on the substrate 100.

  The first ring filter 220 receives the laser light received from the output end of the optical combiner 130 in the direction of the ring waveguide in the direction (+ x direction) perpendicular to the optical axis on the substrate 100 with respect to the output end of the optical combiner 130. Laser light is output from the output end offset by the diameter. The output end of the first ring filter 220 is connected to the input end of the second ring filter 222.

  The second ring filter 222 is a laser beam from the output end obtained by offsetting the light received from the output end of the first ring filter 220 on the substrate 100 in the opposite direction (+ x direction) to the first ring filter 220 by the diameter of the ring waveguide. Output light. That is, the offset direction (+ x direction) from the input end to the output end of the first ring filter is the same as the offset direction (+ x direction) from the input end to the output end of the second ring filter.

The optical path length l ₁ of the ring waveguide of the first ring filter 220 and the center wavelength λ _{1, n} of the pass wavelength band of the first ring filter 220 are λ _{1, n} = l ₁ / n (n is an integer) The relational expression is established. The semiconductor optical device 20 controls the optical path length l ₁ of the ring waveguide of the first ring filter 220 so that the wavelength of the laser beam of the selected laser device 110 is equal to λ _{1, n} .

Similarly, the optical path length l ₂ of the ring waveguide of the second ring filter 222 and the center wavelength λ _{2, m} of the pass wavelength band of the second ring filter 222 are λ _{2, m} = l ₂ / m (m is (Integer) is established. During use of the semiconductor optical device 20, as wavelength and lambda _{2, m} of the laser light of the laser element 110 selected is equal, the optical path length l ₂ of the ring waveguides of the second ring filter 222 are controlled.

For example, when the wavelength of the laser beam output from the selected laser element 110 is λ ₀ , the optical path length l ₁ of the ring waveguide is such that λ ₀ = l ₁ / n ′ = l ₂ / m ′. , L ₂ is adjusted. In addition to l ₁ / n ′, the first ring filter 220 transmits light in a wavelength band in which the center wavelength is l ₁ / n (n is an integer other than n ′ and greater than or equal to 1). Therefore, when the output band of spontaneous emission light includes these pass wavelength bands, light having a plurality of wavelength bands that have passed through the first ring filter 220 is incident on the second ring filter 222.

The second ring filter 222 passes light in a wavelength band in which the center wavelength is l ₁ / m (where m is an integer other than 1 and other than m ′) in addition to l ₁ / m ′. Accordingly, light included in the pass wavelength band of the second ring filter 222 among the light that has passed through the first ring filter 220 passes through the second ring filter 222.

Here, the first ring filter 220 and the second ring filter 222 allow the laser light to pass at a plurality of wavelengths having different intervals in the wavelength band. That is, the optical path length l ₁ of the ring waveguide of the first ring filter 220 and the optical path length l ₂ of the ring waveguide of the second ring filter 222 are set to be different.

Due to the difference between the optical path length l ₁ and the optical path length l ₂ , the pass wavelength bands of the first ring filter 220 and the second ring filter 222 do not completely match, and a part of the pass wavelength band of the first ring filter 220 is: It is included in the shielding wavelength band of the second ring filter 222. Accordingly, light having a wavelength other than the wavelength λ ₀ that passes through the first ring filter 220 is almost shielded by the second ring filter 222.

  As described above, according to the second embodiment, the semiconductor optical device 20 controls the first ring filter 220 and the second ring filter 222, and is controlled by both the first ring filter 220 and the second ring filter 222. The laser beam from the selected laser element 110 among the plurality of laser elements 110 is allowed to pass.

  In FIG. 3, the wavelength selection filter 224 has two ring filters. Alternatively, the wavelength selection filter 224 may include three or more ring filters that are connected in series and have different optical path lengths for the respective ring waveguides. In this case, the semiconductor optical device 20 can further reduce the spontaneous emission light incident on the laser device 110, compared to the case where two or less ring filters are used.

  Next, the operation of the semiconductor optical device 20 in the second embodiment will be described. First, the laser element 110 emits laser light toward the optical combiner 130. The laser light incident on the optical combiner 130 passes through the optical combiner 130 and is output to the first ring filter 220.

  The first ring filter 220 selectively allows the laser light output from the selected laser element 110 to pass therethrough. Accordingly, the laser light passing through the first ring filter 220 is output to the second ring filter 222 with almost no attenuation.

  The second ring filter 222 selectively allows the laser beam output from the selected laser element 110 to pass through. Accordingly, the laser light passing through the second ring filter 222 is output to the semiconductor optical amplifier 140 with almost no attenuation.

  The laser light incident on the semiconductor optical amplifier 140 is amplified by the semiconductor optical amplifier 140 and output to the outside from the output end provided at the end of the semiconductor optical device 20.

  Here, the semiconductor optical amplifier 140 generates spontaneous emission light having a band of several tens of nm in addition to stimulated emission light that is amplified light emitted to the output end of the semiconductor optical device 20. Since the spontaneous emission light of the semiconductor optical amplifier 140 is emitted substantially isotropically, it is also output in the direction of the second ring filter 222.

The spontaneously emitted light is incident on the second ring filter 222 before reaching the optical combiner 130. Here, spontaneous emission light having a wavelength in the cutoff wavelength band of the second ring filter 222 is attenuated by the second ring filter 222. On the other hand, spontaneously emitted light having a wavelength in the pass wavelength band l ₁ / m (m is an integer of 1 or more) of the second ring filter 222 passes through the second ring filter 222 and enters the first ring filter 220. .

The spontaneous emission light incident on the first ring filter 220 is almost attenuated by the first ring filter 220. That is, spontaneously emitted light having a wavelength in the pass wavelength band of the second ring filter 222 and the pass wavelength band l ₁ / n of the first ring filter 220 (n is an integer of 1 or more) passes through the first ring filter 220. pass. Here, since most of the pass wavelength band of the second ring filter 222 is included in the shielding wavelength region of the first ring filter 220, most of the spontaneous emission light that has passed through the second ring filter 222 is the first ring filter 220. Can not pass through and is attenuated.

  As described above, according to the second embodiment described with reference to FIG. 3, the semiconductor optical device 20 uses the two ring filters connected in series to complementarily emit spontaneous emission light incident on the laser device 110. Attenuates effectively. Therefore, the semiconductor optical device 20 according to the second embodiment can output a laser beam having a narrow line width with reduced influence of spontaneous emission light.

  FIG. 4 is a block diagram for explaining a method of controlling the output light wavelength of the semiconductor optical device according to the second embodiment. The semiconductor optical device 20 uses the control unit 260 to control the wavelength of the output light.

  The control unit 260 is electrically connected to the plurality of laser elements 110, the first micro heater 250 and the second micro heater 252. The controller 260 selects the laser element 110 to be used for the output of the semiconductor optical element 10 by supplying a drive current to a selected one of the plurality of laser elements 110.

  The controller 260 controls the current supplied to the first microheater 250 and the second microheater 252. The control unit 260 controls the temperatures of the first microheater 250 and the second microheater 252, and causes the semiconductor optical element 10 to output the laser light output from the selected laser element 110.

Control unit 260, so as to pass a laser beam of the optical path length l ₁ and different optical path lengths l ₂ of the second ring filter 222, and the laser element 110 both ring filter is selected in the first ring filter 220, The first micro heater 250 and the second micro heater 252 are controlled. The control unit 260 may control the first microheater 250 and the second microheater 252 via the wavelength adjustment terminal.

  As described above, according to the method for controlling the semiconductor optical device 20 described with reference to FIG. 4, the semiconductor optical device 20 selects a laser device that outputs laser light having a wavelength to be output by the control unit 260. The laser beam can be output. Further, the semiconductor optical device 20 controls the pass wavelength band of the two ring filters to reduce the spontaneous emission light incident on the laser device 110 while allowing the laser beam output from the selected laser device 110 to pass therethrough. be able to.

  FIG. 5 is a plan view of a semiconductor optical device according to a modification of the second embodiment as viewed from above. In this modification, the first ring filter 220 receives the laser beam received from the output end of the optical combiner 130 in the direction perpendicular to the optical axis on the substrate with respect to the output end of the optical combiner 130 (+ x direction). The laser beam is output from the output end offset by the diameter of the ring waveguide. The output end of the first ring filter 220 is connected to the input end of the second ring filter 222.

  The second ring filter 222 receives the laser beam from the output end offset from the output end of the first ring filter 220 by the diameter of the ring waveguide on the substrate toward the first ring filter 220 (−x direction). Output. That is, the offset direction (+ x direction) from the input end to the output end of the first ring filter 220 is opposite to the offset direction (−x direction) from the input end to the output end of the second ring filter 222.

  By disposing the first ring filter 220 and the second ring filter 222 in this way, the semiconductor optical amplifier 140 connected to the output end of the second ring filter 222 can be disposed near the center of the semiconductor optical element 30. . Further, the output end of the semiconductor optical device 30 extending from the semiconductor optical amplifier 140 can be disposed near the center of the semiconductor optical device 30.

  The semiconductor optical devices 10, 20, and 30 described in the first and second embodiments above can have other members below the surface of the substrate 100 where the laser device 110 is not formed. For example, the semiconductor optical elements 10, 20, and 30 have a temperature adjustment element below the region of the substrate 100 where the laser element 110 is formed. The temperature adjustment element can adjust the wavelength of the output light by adjusting the temperature of the laser element 110.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The execution order of each process such as operations and procedures in the apparatus, system, program, and method shown in the claims, the description, and the drawings is clearly indicated as “before”, “prior”, etc. It should be noted that, unless the output of the previous process is used in the subsequent process, it can be realized in any order. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 10 Semiconductor optical device, 20 Semiconductor optical device, 30 Semiconductor optical device, 100 Substrate, 110 Laser device, 120 Wavelength selection filter, 130 Optical combiner, 140 Semiconductor optical amplifier, 150 Micro heater, 160 Control part, 220 1st ring filter 222 second ring filter, 224 wavelength selection filter, 250 first micro heater, 252 second micro heater, 260 control unit

Claims (8)

A plurality of laser elements;
An optical combiner that is connected to each of the plurality of laser elements via a waveguide and that combines the laser beams output by the plurality of laser elements;
A semiconductor optical amplifier that amplifies the laser light output from the optical combiner;
On the same substrate as the optical combiner and the semiconductor optical amplifier, a plurality of wavelength selective filters respectively formed on a path between each of the plurality of laser elements and the optical combiner;
Equipped with a,
Each of the plurality of laser elements is a wavelength variable light source that outputs laser beams having different wavelengths,
Each of the plurality of wavelength selection filters selectively allows a laser beam output from a corresponding laser element to pass through,
The wavelength band of the laser beam that the plurality of wavelength selection filters pass includes the entire variable wavelength band of the corresponding laser element,
Each of the plurality of wavelength selection filters is a cut-off wavelength band other than the wavelength of the laser light output from the laser element, which is generated by the semiconductor optical amplifier and travels from the optical combiner toward the corresponding laser element. a semiconductor optical device Ru is attenuated in. Wherein the plurality of each of the wavelength selective filter, the semiconductor optical device according to claim 1 is a ring filter formed on the substrate. The semiconductor optical device according to claim 2 , wherein each of the plurality of wavelength selection filters has a variable wavelength band to pass. A plurality of laser elements;
An optical combiner that is connected to each of the plurality of laser elements via a waveguide and that combines the laser beams output by the plurality of laser elements;
A semiconductor optical amplifier that amplifies the laser light output from the optical combiner;
A wavelength selective filter formed on a path between the optical combiner and the semiconductor optical amplifier on the same substrate as the semiconductor optical amplifier;
Equipped with a,
Each of the plurality of laser elements is a wavelength variable light source that outputs laser beams having different wavelengths,
The wavelength selection filter is a variable wavelength selection filter that selectively transmits a wavelength of laser light from a laser element selected from the plurality of laser elements,
The wavelength band of the laser beam transmitted by the wavelength selection filter includes the entire variable wavelength band of the selected laser element,
The wavelength selection filter is a cutoff wavelength other than the wavelength of the laser beam output by the selected laser element, which is generated by the semiconductor optical amplifier and is directed to spontaneous emission light from the semiconductor optical amplifier toward the selected laser element. a semiconductor optical device Ru attenuates the band. The semiconductor optical device according to claim 4 , wherein the wavelength selection filter includes a first ring filter and a second ring filter connected in series. The first ring filter and the second ring filter pass laser beams at a plurality of wavelengths having different intervals in the wavelength band,
The first ring filter and the second ring filter are controlled, and laser light from a laser element selected from the plurality of laser elements is allowed to pass through both the first ring filter and the second ring filter. The semiconductor optical device according to claim 5 . The first ring filter outputs a laser beam from an output end obtained by offsetting the laser beam received from the output end of the optical combiner on the substrate with respect to the output end of the optical combiner,
The second ring filter, the light received from the output end of the first ring filter, to claim 5 or 6 for outputting a laser beam from an output end that is offset in the direction opposite to the first ring filter in said substrate The semiconductor optical device described. A laser element;
A semiconductor optical amplifier for amplifying a laser beam output from the laser element;
A wavelength selection filter formed on a path between the laser element and the semiconductor optical amplifier on the same substrate as the semiconductor optical amplifier;
Equipped with a,
The wavelength selective filter selectively transmits the wavelength of the laser light from the laser element,
The wavelength band of the laser light that the wavelength selective filter passes includes the entire wavelength band of the laser element,
The wavelength selection filter, the semiconductor optical device of the spontaneous emission light directed from said semiconductor optical amplifier to said laser element, Ru attenuates the cutoff wavelength band other than the wavelength of the laser beam which the laser element is output.

Images