JP4473917B2 - Optical signal processing device - Google Patents

Description

  The present invention relates to an optical signal processing device. More specifically, the present invention relates to temperature compensation of an optical signal processing device including a spectroscopic element.

  As the speed and capacity of optical communication networks have increased, there has been an increasing need for optical signal processing apparatuses such as those represented by processing of wavelength division multiplexing (WDM) transmission signals. For example, there is a demand for a function of switching the path of multiplexed optical signals between nodes. An optical signal processing apparatus has been increased in speed by performing path conversion without changing the optical-electrical conversion.

  On the other hand, from the viewpoint of miniaturization and integration of signal processing devices, research and development of waveguide type optical circuits (PLCs) are in progress. In the PLC, for example, a core made of quartz glass is formed on a silicon substrate and various functions are integrated in one chip, and an optical functional device with low loss and high reliability is realized. Furthermore, a composite optical signal processing component (apparatus) that combines a plurality of PLC chips and other optical functional components has also appeared.

  For example, Patent Document 1 discloses an optical signal processing device in which a waveguide type optical circuit (PLC) including AWG or the like and a spatial modulation element such as a liquid crystal element are combined. More specifically, a wavelength blocker including a PLC and a collimating lens arranged symmetrically with respect to the liquid crystal element, a wavelength equalizer, a dispersion compensator, and the like are being studied. In these optical signal processing devices, optical signal processing is performed independently for each wavelength for a plurality of optical signals having different wavelengths.

  FIG. 5 is a conceptual diagram illustrating an example of an optical signal processing apparatus. In this optical signal processing apparatus, an optical signal is input / output via the spectroscopic element 51. The spectroscopic element 51 demultiplexes a plurality of optical signals having different wavelengths at an emission angle θ corresponding to the wavelengths. The demultiplexed optical signal is emitted toward the condenser lens 52. The optical signal condensed by the condenser lens 52 is condensed at predetermined positions on the signal processing element 53 having a function of intensity modulation, phase modulation or deflection corresponding to the emission angle θ. That is, it should be noted that the optical signal is collected at different positions of the signal processing element according to the wavelength of the input optical signal. The signal processing element 53 is, for example, a liquid crystal element composed of a plurality of element elements (pixels). By controlling the transmittance of each element, the optical signal of each wavelength is subjected to intensity modulation and the like, and a predetermined signal processing function is realized for each wavelength. The signal-processed optical signal is reflected by the mirror 54, reverses the traveling direction, passes through the condenser lens 53 again, and is multiplexed in the spectroscopic element 51. The combined optical signals of the respective wavelengths are output to the outside of the optical signal processing apparatus again as output light.

  In FIG. 5, the spectroscopic element 51 is conceptually shown, and may be any element that can demultiplex and multiplex optical signals according to the wavelength. For example, there are a grating, a prism, and an arrayed waveguide grating (AWG). The signal processing element only needs to be capable of modulating the intensity or phase of the optical signal, or the intensity and phase, or capable of deflecting the traveling direction of the optical signal. For example, there are a liquid crystal element, a MEMS (Micro Electro Mechanical Systems) mirror, a non-linear crystal, and the like.

  The optical signal processing apparatus shown in FIG. 5 is configured to perform both demultiplexing and multiplexing of an optical signal by one spectroscopic element by folding the optical signal using a mirror. This configuration is generally called a reflection type. Optical signal processing such as wavelength blocking is not limited to this configuration. For example, without using a mirror, the signal processing element shown in FIG. 5 is positioned on the axis of symmetry, and the output system is composed of another lens and a spectroscopic element on the opposite side of the incident system on the extension line of the incident light optical axis. It is also possible to have a configuration in which This configuration is a configuration that performs demultiplexing and multiplexing of optical signals via independent incident and outgoing systems, respectively, and is called a transmission type. Further, in the apparatus configuration shown in FIG. 5, it is possible to combine the optical signals by changing the direction of the mirror and using an emission system including another lens and a spectroscopic element arranged at an arbitrary position. . For example, it is also possible to configure the exit system with a lens and a spectroscopic element arranged in a direction perpendicular to the incident optical path with the mirror reflecting surface inclined by 45 degrees with respect to the incident optical path of the optical signal. Further, when the signal processing element has a deflection function, a plurality of emission systems can be provided.

  In FIG. 5, the spectroscopic element 51 and the condensing lens 52 are arranged apart from each other by a front focal length FFL, and the signal processing element 53 and the condensing lens 52 are arranged apart from each other by a rear focal length BFL. The focal point of the light collected by the condenser lens 52 must be on the surface of the mirror 54 at all wavelengths used. When deviating from the mirror surface, there arises a problem of causing a coupling loss between input and output light. At the same time, since the beam spot diameter of the collected optical signal on the signal processing element surface is increased, there arises a problem that the wavelength resolution is lowered.

  Further, the signal processing element 53 needs to have a spatially periodic structure so that it can selectively modulate for each wavelength of the optical signal. For example, when the signal processing element 53 is a liquid crystal element, the structure of a plurality of element elements in the liquid crystal element must be designed in accordance with the optical characteristics of the spectroscopic element and the condenser lens.

  More specifically, it is known that the wavelength dependence of the condensing position on the signal processing element follows the product of the angular dispersion value of the spectroscopic element and the focal length of the condensing lens. The wavelength dependence of the light collection position is also called a linear dispersion value of the spectroscopic optical system. The linear dispersion value of the optical system determined by the spectroscopic element and the condensing lens needs to be sufficiently coincident with the linear dispersion value used for designing the structure of the signal processing element. If there is a deviation between these linear dispersion values, the actual focal point position of the optical signal will not coincide with the position of the individual element elements (for example, pixels of the liquid crystal shutter element) of the signal processing element. Due to this mismatch, an error occurs in the wavelength of the optical signal actually processed.

Japanese Patent Laid-Open No. 2002-250828 (pages 16, 19, 20, 20, 27, 29D, etc.) JP 2001-255424 A L. Grave de Peralta and 4 others, “Control of Center Wavelength in Reflective-Arrayed Waveguide-Grating Multiplexers”, IEEE JOURNAL OF QUANTUM ELECTRONICS, DECEMBER 2004, VOL. 40, NO. 12, page 1725-1731 Shinichi Hasegawa and one other, “Athermal AWG module with multi-compensation plate that has an extremely low temperature dependence (<+/− 5 ppm)”, Proceedings of the 2007 IEICE General Conference, C-3-89, 245 pages

  However, the conventional optical signal processing apparatus has a problem that the performance of the optical signal processing apparatus deteriorates due to the temperature because the spectral characteristic of the spectral element has temperature dependency. In the optical signal processing apparatus having the configuration shown in FIG. 5, a case where the spectroscopic element is an AWG is considered. Even if the optical signals have the same wavelength, the position of the condensing point on the signal processing element varies when the emission angle changes depending on the temperature. For this reason, temperature dependence occurs in the wavelength of light that is actually subjected to signal processing. In the case of an AWG composed of a quartz glass material, there is a temperature dependence of about 0.011 nm / ° C. Assuming that the operating temperature range of the optical signal processing apparatus is 0 to 70 ° C., a maximum wavelength error of 0.77 nm occurs within this temperature range.

  Conventionally, in order to eliminate the temperature dependence of the spectral characteristics of the AWG, it has been studied to reduce the temperature dependence of the AWG itself. For example, Patent Document 2 discloses a technique for compensating for the temperature dependence of AWG by forming a plurality of characteristic grooves for dividing the core on an array waveguide of AWG and filling different materials. ing. According to this technique, an excess loss of about 1 dB cannot be avoided by forming the groove. Even when the shape of the groove is optimized, the excess radiation loss due to the optical signal radiation in the direction perpendicular to the AWG substrate cannot be sufficiently suppressed. Furthermore, in order to form the groove structure, a complicated additional manufacturing process is required, and there is a problem that the manufacturing cost of the AWG increases.

  There has also been proposed a method for compensating for a temperature variation caused by the AWG by using some mechanical component and a mechanical mechanism outside the AWG. For example, Non-Patent Document 1 discloses a method of offsetting the temperature dependence of the emission angle from the AWG by changing the mirror direction or the like according to the detected temperature and changing the optical path. However, when the function of the optical signal processing device is advanced and the size of the device is increased to some extent, a temperature compensation error may occur due to uneven temperature distribution inside the device. For example, when a liquid crystal element is used as the signal processing element, the temperature in the vicinity of the liquid crystal element may reach about 60 ° C. because the liquid crystal element itself is heated to ensure the response speed of the liquid crystal element. In such a case, it becomes impossible to make the temperature of the AWG having a large temperature characteristic uniform with the temperature of the liquid crystal element separated by a spatial light path such as a lens. Furthermore, when the variation in the external environment temperature of the optical signal processing device is added, the temperature compensation error due to non-uniformity in the temperature compensation system increases. In order to keep the temperature of the entire apparatus uniform according to the liquid crystal element, a large constant temperature structure is required, which leads to an increase in the size and cost of the apparatus. The device power consumption for keeping the temperature of the entire device constant also increases.

  In addition, when a simple mechanical mechanism is used, since only linear compensation can be normally performed with respect to temperature, it is not possible to sufficiently compensate for a second-order fluctuation component in the temperature-dependent characteristics of the AWG. Non-Patent Document 1 proposes a method of reducing the temperature dependence of the AWG to ± 0.005 nm by paying attention to compensation of the temperature-dependent secondary fluctuation component. However, it is necessary to provide a very complicated compensator on the AWG, and the complicated structure causes the high cost of the AWG as in Patent Document 2.

  As described above, it has been required to solve the problem of temperature fluctuation in the performance of the optical signal processing apparatus due to the temperature dependence of the spectral characteristics of the AWG in a simpler and lower cost method. Furthermore, it has been desired to prevent an increase in temperature compensation error when the temperature distribution is uneven in the optical signal processing apparatus, and to further reduce the temperature-dependent secondary fluctuation component of the AWG.

  In order to achieve such an object, the present invention according to claim 1 divides an optical signal into a plurality of optical signals having different wavelengths and performs signal processing on the optical signals of the respective wavelengths. In the optical signal processing apparatus for performing the above, the spectral means for splitting into a plurality of optical signals having different wavelengths at an emission angle according to the wavelength of the optical signal, and disposed on or near the spectral means, the temperature of the spectral means is set. Temperature detecting means for detecting; condensing means for condensing the optical signal emitted from the spectroscopic means; signal processing means for modulating the optical signal collected by the condensing means; the spectroscopic means; A plurality of optical path conversion means arranged in the optical path between the light collecting means and bending the optical path of the optical signal, including a first support and a second support that fix the position of the optical path conversion means. A plurality of supports. In the vicinity of at least one support in the body, temperature variable means for changing the length by heating or cooling is arranged, and based on the temperature detected by the temperature detection means, the temperature variable means allows the temperature variable means to change the length. The optical signal through the optical path changing means so as to offset the temperature dependence of the emission angle of the spectroscopic means by displacing the position or shape of the optical path changing means by changing the length of at least one support. An optical signal processing apparatus comprising: bending the optical path of the optical signal processing apparatus.

  According to a second aspect of the present invention, in the signal processing device according to the first aspect, at least one of the two or more supports is a support having a different length or a different thermal expansion coefficient from the remaining supports. A displacement depending on the temperature of the position or shape of the optical path changing means caused by the difference in length or the coefficient of thermal expansion cancels the temperature dependence of the emission angle of the spectroscopic means. The optical path of the optical signal passing through the optical path changing means is bent.

  A third aspect of the present invention is the signal processing apparatus according to the first or second aspect, wherein the heating or cooling calorific value data given by the temperature variable means for canceling the temperature variation of the emission angle of the spectroscopic means is stored, and the temperature The apparatus further comprises control means for controlling heating or cooling heat amount of the temperature variable means based on a temperature display signal from the detection means and the stored data.

  According to a fourth aspect of the present invention, in the signal processing device according to the third aspect of the present invention, the signal processing device further includes a second temperature detection unit that detects the temperature of the support in the vicinity of the temperature variable unit, and the first temperature detection unit. The temperature variable means is controlled based on each temperature display signal from the second temperature detecting means and the stored data.

  According to a fifth aspect of the present invention, in the signal processing device according to any one of the first to fourth aspects, the optical path changing means is a mirror held by two supports or a prism held by two supports. It is characterized by.

  According to a sixth aspect of the present invention, in the signal processing device according to the second aspect, the optical signal is split into a plurality of optical signals having different wavelengths and the signal processing is performed on the optical signals of the respective wavelengths. In the processing apparatus, a spectroscopic unit that splits a plurality of optical signals having different wavelengths at an emission angle according to the wavelength of the optical signal, and a temperature detector that is disposed on or in the vicinity of the spectroscopic unit and detects the temperature of the spectroscopic unit Means, condensing means for condensing the optical signal emitted from the spectroscopic means, and signal processing means for modulating the optical signal collected by the condensing means, the spectroscopic means, A plurality of supports including a first support and a second support, and at least one of the plurality of supports is heated or cooled by a length of the support. Temperature variable means to change by Based on the temperature detected by the temperature detecting means, the temperature varying means changes the length of the at least one support so as to displace the position of the spectroscopic means, whereby the emission angle of the spectroscopic means It is an optical signal processing device characterized by canceling the temperature dependence of.

  According to a seventh aspect of the present invention, in the signal processing device according to the sixth aspect, at least one of the two or more supports has a different length or a different coefficient of thermal expansion from the other support. The temperature dependence of the emission angle of the spectroscopic means is offset by a temperature-dependent displacement of the spectroscopic means caused by a difference in length or a coefficient of thermal expansion between the supports. .

  The invention according to claim 8 is the signal processing apparatus according to any one of claims 1 to 7, wherein the spectroscopic means is an AWG.

  As described above, according to the present invention, the temperature variation of the performance of the optical signal processing device due to the temperature dependence of the spectral characteristics of the AWG is compensated for temperature in the spatial optical system, thereby making it easier and less expensive. The temperature can be made independent by the method. In particular, it is possible to effectively compensate for temperature dependent secondary fluctuation components.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The optical signal processing apparatus of the present invention performs temperature compensation on the temperature dependence of the spectral characteristics of the AWG by changing the direction of the optical path using the temperature-dependent displacement of the support of the optical component in the spatial optical system. Due to the temperature compensation action in the spatial optical system, sufficient temperature independence of the optical characteristics can be realized with a simpler configuration than the prior art. In particular, it is possible to effectively compensate for the temperature-dependent secondary fluctuation component of the AWG. Temperature compensation in the AWG element itself becomes unnecessary, and the manufacturing process of the AWG is simplified to realize cost reduction.

“First Example”:
FIG. 1 is a diagram showing a configuration of an optical path bending mirror for temperature compensation of an optical signal processing apparatus according to a first embodiment of the present invention. FIG. 2 is an overall configuration diagram of the optical signal processing apparatus of the present invention including the optical path bending mirror shown in FIG. The optical signal processing apparatus according to the present invention is described as an example of a reflective configuration including an optical path folding mirror in FIG. 1, but may be a transmissive optical signal processing apparatus using an optical path folding mirror.

FIG. 1 shows a configuration in the vicinity of an optical path bending mirror 1 inserted into an optical path in a spatial optical system in a reflection type optical signal processing apparatus to be described later. The mirror 1 is inserted between the condenser lens and the AWG, and changes the direction of the optical path by reflecting an optical signal on the surface of the mirror 1. The mirror 1 is fixed to the fixed bases 3a and 3b by two supports 2a and 2b at two locations. Support 2a, 2b has a length are each L _r, are fixed at intervals L _d. The support may be made of a material that can stably hold the mirror position in the apparatus against vibration and the like and that has an appropriate thermal expansion coefficient so as to be deformed by thermal expansion due to temperature change. The shape of the supports 2a and 2b is not particularly limited, and may be a rod shape or a column shape. Examples of the material for the support include aluminum, stainless steel, and a plastic material.

  The fixed bases 3a and 3b may be a base material of the optical signal processing device. The two fixed bases may be integrated. One support body 2b is provided with temperature variable means, specifically, a heater 4. The heater 4 is connected to a heater driving power source 5 for heating the support. The heater drive power supply 5 is controlled by a control signal from the control means 10 so that the heating amount of the support 2b by the heater 4 is appropriate.

  Since the amount of heat given from the heater 4 to the support 2b is controlled by a control signal from the control means 10, the length Lr of the support 2b varies with temperature in accordance with the control signal. Since the other support 2a is not heated, the length of each support varies depending on the temperature difference between the two supports 2a and 2b. As a result, the inclination angle of the mirror 1 with respect to the optical path of the optical signal changes, and the direction of the optical path can be changed.

  The tilt angle of the mirror 1 can be controlled such that the control signal is changed according to the temperature of the AWG so as to cancel out the fluctuation of the emission angle due to the temperature dependence of the AWG. The relationship of the heater heating amount Q that gives a required tilt angle to the mirror 1 can be obtained in advance with respect to the temperature difference ΔT of the AWG temperature from the reference temperature. The control means 10 may store control information for generating a necessary control signal that gives the heater heating amount Q. The control means 10 may be a computer including a memory that stores control information. That is, based on the control data corresponding to each ΔT, a control signal is generated to realize predetermined heater heating.

  FIG. 2 is an overall configuration diagram of the optical signal processing apparatus of the present invention including the above-described optical path bending mirror. The optical path of the spatial optical system in the reflective optical signal processing device shown in FIG. 5 is configured to be bent by the optical path bending mirror 1 disposed between the condenser lens and the AWG. That is, the optical signal emitted from the AWG 11 is bent at an almost right angle by the optical path bending mirror 1 and is collected by the condenser lens 12. Further, the collected optical signal is subjected to signal processing by an optical signal processing element 13 such as a liquid crystal element. Thereafter, the optical signal is reflected by the mirror 14 and travels toward the AWG 11 along the same optical path as the forward path.

  The AWG 11 includes a slab waveguide 15 and an arrayed waveguide 16, and is emitted from the end face A at an emission angle corresponding to the wavelength of the optical signal. A temperature sensor 17 is installed on the AWG 11, and a temperature detection signal is output from the temperature sensor 17. The temperature detection signal is supplied to the control means 10, and the control means 10 determines the temperature of the AWG based on the control signal. The temperature sensor 17 may not necessarily be on the AWG 11 as long as the temperature of the AWG 11 can be detected. The optical path bending mirror 1 is arranged on the optical path between the exit end face A of the AWG 11 and the condenser lens 12 so as to bend the optical path, preferably at a position close to the AWG. Depending on the arrangement configuration of the optical components in the optical signal processing apparatus, the bending angle of the optical path by the optical path bending mirror is not limited to the right angle (90 °) as shown in FIG.

  One support is heated with a heater so that the optical path bending mirror is tilted in a direction that cancels the temperature dependence of the emission angle of the optical signal at the end face A of the AWG 11. Therefore, either one of the supports is heated according to the polarity of the temperature characteristics of the AWG and the thermal expansion characteristics of the support. As shown in FIG. 2, the configuration is not limited to the configuration in which the heater 4 is attached to the support 2 b on the side close to the AWG 17. The inclination angle of the optical path bending mirror 1 is determined by the difference in length between the two supports.

  The inclination angle may be controlled by attaching heaters to both the supports 2a and 2b and controlling the amount of heating. When the heaters are independently attached to the two supports, the inclination angle of the optical path bending mirror 1 can be changed in any direction by adjusting the heating amount of each heater. In this case, the inclination angle of the optical path bending mirror 1 can be uniquely determined for the combination of the heating amounts applied by the two heaters.

  Although not shown in FIG. 2, another temperature sensor can be provided near the support, and the temperature compensation control can be performed with higher accuracy by the control means 10 including the temperature information of the support.

Next, more specific examples will be described. In FIG. 1, the support material is aluminum, the support length Lr is 10 mm, and the distance Ld between the two supports is 10 mm. When the thermal expansion coefficient of aluminum is α _AL (1 / ° C.), the amount of change Δθ in reflection angle per 1 ° C. of the optical path bending mirror at this time is expressed by the following equation.
Δθ = α _AL × Lr / Ld Equation (1)
As α _AL = 23 × 10 ⁻⁶ , Δθ = 0.00131 degrees / ° C. is obtained from the equation (1). When an AWG having an angular dispersion of 0.13 degrees / nm is used, a wavelength correction of 0.8 nm can be performed by heating the heater to 80 ° C. This wavelength correction amount is an amount sufficient to compensate for a wavelength error of 0.77 nm in the operating temperature range of 0 to 70 ° C. of the optical signal processing device described above.

  In this embodiment, the optical path bending mirror 1 is arranged in the optical path between the AWG 11 and the condenser lens 12. However, if the optical path bending mirror 1 is arranged closer to the AWG 11, the translational deviation at the time of optical path bending becomes smaller and the loss occurs. The increase in becomes smaller. In the present invention, the temperature compensation for the temperature dependence of the AWG is performed using the bending mirror 1, but the AWG itself is supported by a similar support mechanism, and the rotation angle in the spectral plane is controlled. It was also noted that the same effect as the rotation of the bending mirror can be obtained. Further, it is needless to say that the same effect can be obtained as long as it is an optical component that can be disposed between the AWG 11 and the condenser lens 12 and the amount of bending of the optical path can be changed by its rotation. Such an optical component is not limited to the above-described optical path bending mirror 1, and includes, for example, a prism.

“Second Example”:
FIG. 3 is a diagram showing a configuration of an optical path bending mirror for temperature compensation of the optical signal processing apparatus according to the second embodiment of the present invention. FIG. 4 is an overall configuration diagram of the optical signal processing device of the present invention including the optical path bending mirror shown in FIG. Compared to the first embodiment, the two supports 2a and 2b are different in that the length is different. That is, the length Lr2 of the first support 2c is shorter than the length Lr1 of the second support 2b, and has a difference of ΔL between the supports.

  In the optical path conversion mirror having the configuration shown in FIG. 3, when the ambient temperature of the optical path conversion mirror 1 fluctuates substantially in conjunction with the temperature of the entire optical signal processing apparatus and the AWG, the length of the two supports 2b and 2c Since there is a difference ΔL, there is a difference between the two supports in each amount of change in thermal expansion. As a result, the tilt angle of the mirror 1 can be changed with the temperature by this difference in the amount of change in thermal expansion without heating by the heater 4. Therefore, the temperature compensation function can be realized by setting the support length of the optical path conversion mirror 1 to an appropriate different length so that the variation in the emission angle from the end face A due to the temperature dependence of the AWG can be offset. When the primary fluctuation component is large in the temperature dependence as in AWG, the primary fluctuation can be canceled by utilizing the temperature compensation caused by the above-described difference in the support length ΔL.

  Further, in the present embodiment, a heater 4 is attached to the second support 2b, and the support 2b is heated and controlled in accordance with a control signal from the control means 10. Since the temperature-dependent primary fluctuation component is compensated using the temperature compensation function based on the difference in the length of the support, the remaining secondary fluctuation component may be compensated by heating the heater. Compared to the first embodiment, since the control amount for temperature compensation by the heater is small, less power is required for driving the heater.

FIG. 4 is an overall configuration diagram of the optical signal processing apparatus of the present invention including the optical path bending mirror of FIG. 3 described above. Compared with the optical signal processing apparatus shown in FIG. 2, the configuration of the optical path bending mirror 1 and the configuration of the temperature sensor are different, but the others are the same. In this embodiment, in order to detect the temperature in the apparatus, a temperature sensor 17a for the AWG 11 and a temperature sensor 17b attached in the vicinity of the support for the optical path bending mirror are provided. As described in FIG. 3, the optical path bending mirror of the present embodiment acts so that the inclination angle of the optical path bending mirror changes depending on the ambient temperature of the optical path bending mirror. Therefore, the temperature sensor 17b to which the temperature near the support is added. If detected, the temperature-dependent secondary fluctuation component can be compensated more accurately. Temperature detection signals T _AWG and T _rod are supplied from the temperature sensors 17 a and 17 b to the control means 10, respectively. If the AWG 11 and the optical path bending mirror 1 are close to each other and there is almost no temperature difference between them, the temperature sensor 17b is not essential.

Next, more specific examples will be described. In FIG. 3, the material of the support was aluminum, the difference ΔL between the two support lengths was 11.3 mm, and the distance Ld between the two supports was 10 mm. When the thermal expansion coefficient of aluminum is α _AL = 23 × 10 ⁻⁶ (1 / ° C.), the amount of change Δθ in reflection angle per 1 ° C. by the optical path bending mirror at this time is calculated from the following (1), and Δθ = 0.0015 degrees / ° C is obtained.

  On the other hand, considering the temperature dependence of spectral characteristics of AWG in general, AWG without temperature compensation has a temperature dependence of about 0.011 nm / ° C. If this is converted into an optical frequency, it corresponds to 1.3 GHz / ° C. Furthermore, if the focal length is 100 mm and the linear dispersion value of the optical signal processing apparatus is 2 μm / GHz, the temperature dependence of the above-mentioned general AWG is 0.0015 degrees / ° C. in terms of the emission angle.

  Therefore, it can be seen that the temperature dependence of a general AWG can be offset by the optical path conversion mirror configuration of the specific embodiment described above. In FIG. 4, if there is no temperature difference between the AWG 11 and the optical path conversion mirror 1, the temperature compensation function based on the difference in the length of the support is sufficient even without control by heater heating. When there is a temperature difference between the AWG 11 and the optical path conversion mirror 1 in the apparatus, or for temperature-dependent secondary fluctuation components, the temperature compensation control can be performed with higher accuracy by the heater 4.

  In any of the above-described embodiments, a heater is used as means for changing the length of the support. However, the present invention is not limited to this as long as the temperature of the support can be varied. For example, a cooling element or the like may be included.

  In each of the above embodiments, the optical signal processing apparatus having the reflection type configuration has been described as an example. However, it goes without saying that the present invention is not limited to the reflection type configuration. That is, the present invention can be applied to an optical signal processing apparatus having a transmission type structure in which an optical path is bent or a structure having a plurality of emission systems or incident systems.

  Further, in the above-described embodiment, an example in which temperature compensation is performed using the support member of the optical path conversion mirror disposed in the optical path between the AWG and the condenser lens is shown, but the present invention is not limited thereto. For example, controlling the converging lens to translate relative to the support of the condensing lens has the same effect as bending the optical path, so that similar temperature compensation can be performed. Please keep in mind.

  As described above, according to the present invention, the temperature variation of the optical signal processing apparatus caused by the temperature dependence of the spectral characteristics of the AWG is compensated for temperature in the spatial optical system, thereby making the method simpler and lower cost. Can be made temperature-independent. The optical coupling loss in the spatial optical system of the optical signal processing device can be greatly reduced over a wide temperature range. Due to the temperature compensation action in the spatial optical system, sufficient temperature independence of the optical characteristics can be realized with a simpler configuration than the prior art. In particular, it is possible to effectively compensate for the second-order fluctuation component of the temperature dependence of the AWG. It becomes possible to eliminate the need for temperature compensation in the AWG element itself, and further, the manufacturing process of the AWG can be simplified to reduce the cost of the entire optical signal processing apparatus.

  It can be used for an optical signal processing device used for optical communication. It can be applied to wavelength blockers, wavelength equalizers, wavelength tunable filters, dispersion compensators, and so on.

It is a block diagram of the optical path conversion mirror which concerns on 1st Example of this invention. It is a block diagram of the optical signal processing apparatus with a temperature compensation function which concerns on a 1st Example. It is a block diagram of the optical path conversion mirror which concerns on the 2nd Example of this invention. It is a block diagram of the optical signal processing apparatus with a temperature compensation function which concerns on a 2nd Example. It is a conceptual diagram of an optical signal processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical path conversion mirror 2a, 2b, 2c Support body 3a, 3b Fixed base 4 Heater 5 Heater drive power supply 10 Control means 11 AWG
12, 52 condenser lens
13, 53 Signal processing element 14, 54 Mirror 17, 17a, 17b Temperature sensor 20 Optical signal processing device

Claims (8)

In an optical signal processing device that splits an optical signal into a plurality of optical signals of different wavelengths and performs signal processing on the optical signals of each wavelength,
A spectroscopic means for splitting a plurality of optical signals having different wavelengths at an emission angle according to the wavelength of the optical signal;
A temperature detecting means disposed on or near the spectroscopic means for detecting the temperature of the spectroscopic means;
Condensing means for condensing the optical signal emitted from the spectroscopic means;
Signal processing means for modulating the optical signal collected by the light collecting means;
An optical path conversion unit disposed in an optical path between the spectroscopic unit and the light collecting unit, and which bends the optical path of the optical signal, the first support and the second support fixing the position of the optical path conversion unit A plurality of supports including a support, and in the vicinity of at least one of the plurality of supports, temperature varying means for changing the length by heating or cooling is disposed, and the temperature detection Based on the temperature detected by the means, the temperature variable means changes the length or the shape of the optical path changing means by changing the length of the at least one support, and the temperature dependence of the emission angle of the spectroscopic means An optical signal processing apparatus comprising: bending an optical path of the optical signal via the optical path conversion means so as to cancel out the characteristics.   At least one of the two or more supports is a support having a different length or a different coefficient of thermal expansion from the remaining supports, and the difference caused by the difference in the length or the coefficient of thermal expansion. The optical path of the optical signal passing through the optical path converting means is bent so that the displacement depending on the temperature of the position or shape of the optical path converting means cancels the temperature dependence of the emission angle of the spectroscopic means. The optical signal processing apparatus according to claim 1.   Heating or cooling calorie data given by the temperature varying means that cancels temperature fluctuations of the emission angle of the spectroscopic means is stored, and the temperature variable based on the temperature display signal from the temperature detecting means and the stored data The optical signal processing apparatus according to claim 1, further comprising control means for controlling a heating or cooling heat amount of the means.   Second temperature detection means for detecting the temperature of the support in the vicinity of the temperature variable means is further provided, and each temperature display signal from the first temperature detection means and the second temperature detection means is stored and stored. 4. The optical signal processing apparatus according to claim 3, wherein the temperature variable means is controlled based on the data.   5. The optical signal processing apparatus according to claim 1, wherein the optical path changing means is a mirror held by two supports or a prism held by two supports. In an optical signal processing device that splits an optical signal into a plurality of optical signals of different wavelengths and performs signal processing on the optical signals of each wavelength,
A spectroscopic means for splitting a plurality of optical signals having different wavelengths at an emission angle according to the wavelength of the optical signal;
A temperature detecting means disposed on or near the spectroscopic means for detecting the temperature of the spectroscopic means;
Condensing means for condensing the optical signal emitted from the spectroscopic means;
Signal processing means for modulating the optical signal collected by the light collecting means,
The spectroscopic means has a plurality of supports including a first support and a second support that fix the position, and at least one of the plurality of supports includes the support. Temperature varying means for changing the length of the at least one support by the temperature varying means based on the temperature detected by the temperature detecting means, and the spectroscopic means. The optical signal processing apparatus is characterized in that the temperature dependence of the emission angle of the spectroscopic means is canceled by displacing the position of the light beam.   At least one of the two or more supports has a length different from that of the other support or a different coefficient of thermal expansion, and is caused by a difference in length or a coefficient of thermal expansion between the supports. The optical signal processing apparatus according to claim 6, wherein the temperature dependence of the emission angle of the spectroscopic means is canceled by a displacement depending on the temperature of the position of the spectroscopic means.   8. The optical signal processing apparatus according to claim 1, wherein the spectroscopic means is an AWG.

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