Integrated photon transmission circuit capable of operating over extended temperature range

Abstract

The invention relates to an integrated photon transmission circuit (1) comprising: a laser source (LS) for generating optical radiation and comprising a grating defining a transmission wavelength (LBragg) and a first amplification medium (A1) having a first photoluminescence wavelength (L1); and a semiconductor optical amplifier (SOA) comprising a second amplification medium (A2) having a second photoluminescence wavelength (Lgain). According to the invention, the laser source (LS) and the optical amplifier (SOA) are configured such that: at a first temperature (T0), the transmission wavelength (Lbrag) is closer to the first photoluminescence wavelength (L1) than the second wavelength (Lgain); and at a second temperature (T1), the transmission wavelength (Lbrag) is closer to the second photoluminescence wavelength (Lgain) than the first wavelength (L1).

Description

Technical Field

[0001] The present invention relates to an integrated photonic transmission circuit. Such a circuit can be used in the field of telecommunications to create transmission components or in the field of sensors, for example to create LiDAR components. Background Art

[0002] Integrated photonic circuits are integrated circuits capable of generating, detecting, or manipulating optical radiation. Similar to electronic integrated circuits, these circuits can integrate multiple functional blocks, such as laser sources, switches, modulators, amplifiers, and power dividers, on a single substrate (e.g., silicon-based), interconnected by waveguides.

[0003] The integrated photonic transmission circuit is equipped with an optical radiation source, typically a laser source. In a manner known per se (see, for example, EP2811593), this light source comprises an optical amplifying medium formed from a layer stack of III-V materials, which forms at least one heterojunction or so-called "active" region, such as multiple quantum wells. This stack can be made of materials selected from the following non-exhaustive list: InP, AsGa, InGaAlAs, InGaAsP, InAsP. The choice of materials used for this stack defines the photoluminescence wavelength of the amplifying medium. The amplifying medium is characterized by its amplification gain, which is a function of wavelength. This function peaks at the "photoluminescence" wavelength and decreases on either side of it, thereby defining an amplification bandwidth of typically approximately 30 nm.

[0004] For example, an amplifying medium is arranged in a strip shape and aligned with a portion of a waveguide (called a coupling section), such as one made of silicon. Current is passed through the medium to electrically pump it, thereby establishing a hybrid optical mode in the amplifying medium and the waveguide section. The laser effect is achieved by a feedback structure that forms a resonant cavity. This structure can be generated using a distributed reflector (such as a Bragg grating) arranged in the amplifying medium or waveguide. The Bragg grating defines the transmission wavelength of the optical radiation generated by the laser source. The hybrid optical mode formed in the amplifying medium and in the coupling section of the underlying waveguide tends to propagate in the waveguide.

[0005] EP3538937 proposes forming such laser sources (and other active components of integrated photonic circuits) through "chip bonding," i.e., using layer transfer techniques to transfer a portion of III-V material onto the waveguide coupling portion. In other approaches, a portion of the III-V material layer forming the amplifying medium is deposited onto the waveguide coupling portion, for example, by epitaxial deposition. This portion of material is processed, particularly by etching, to form electrical contacts on both sides of the junction, thereby forming a functional laser diode. If the goal is to produce multiple active components (e.g., multiple laser sources), this portion of III-V material can also be structured to individualize multiple diodes arranged across multiple waveguide coupling portions. This approach (details and variations of which can be found in the aforementioned EP3538937) is highly advantageous in simplifying the fabrication of integrated photonic transmission circuits. This is particularly true when these circuits include multiple active components with the amplifying medium made of the same material, as it allows for collective fabrication of these active components.

[0006] In order to generate optical radiation with a satisfactory power, the transmission wavelength of the optical radiation (defined by the period of the Bragg grating) and the photoluminescence wavelength of the amplifying medium (defined by the properties of the materials defining the stack) are selected to match each other. At the very least, an effort is made to ensure that the transmission wavelength of the light beam lies within the amplification bandwidth of the amplifying medium.

[0007] However, as reviewed in US2011211603, these wavelengths drift with the operating temperature of the laser source. Therefore, the transmission wavelength of the optical radiation (hereinafter referred to as L bragg ) tends to increase with increasing temperature, the increase being of the order of 0.1 nm / ° C. However, the gain function and the gain peak of the amplifying medium tend to increase with temperature in a more pronounced manner, being of the order of 0.6 nm / ° C.

[0008] [ Figure 1 ] shows the gain L1 and transmission wavelength L of the amplifying medium of the prior art laser source bragg The evolution of the differential drift is plotted in decibel (dB) / wavelength (nm). It shows the phenomena that occur at three elevated temperatures, T0, T1, and T2, due to these differential drifts. First, it will be noted that the gain functions G(T0), G(T1), and G(T2) of the amplifying medium, and in particular the amplitude of the gain peaks, tend to decrease with temperature.

[0009] At a relatively low operating temperature T0, the transmission wavelength L bragg (T0) is within the gain bandwidth of the amplifying medium and has a wavelength greater than the wavelength of the gain peak, L1(T0). braggThe gain is not maximum at (T0), but this situation is not detrimental because at the relatively low temperature T0, the gain is still relatively high. Thus, the transmitted power of the radiation can be satisfactory.

[0010] At the intermediate operating temperature T1, the transmission wavelength L bragg (T1) is arranged at a wavelength close to the wavelength of the gain peak L1(T1). This situation is advantageous because the amplification provided is at or close to its maximum.

[0011] At the relatively high operating temperature T2, the transmission wavelength L bragg (T2) is then arranged in a lower bandwidth part of the gain of the amplification medium, at a wavelength shorter than the wavelength of the gain peak L1(T2). This situation is detrimental because it combines a gain function weakened by the relatively high operating temperature, and a transmission wavelength L bragg (T2) located in a part far from the peak of this function. Thus, the power of the emitted light is particularly low.

[0012] It should thus be understood that the laser source is able to produce, over a limited operating temperature range, in the example of [T0, T1], a satisfactory (above a required power threshold) power of the optical radiation. Figure 1

[0013] To increase the power of the optical radiation produced by the light source, a semiconductor optical amplifier (SOA) can be added to the laser source and integrated into an integrated photonic circuit. An example of such an integrated circuit is particularly described in the document US2013107900. This amplifier is arranged end to end with the laser source (i.e. without intermediate waveguides), and like the laser source, has an amplification medium made of the same material as the light source. Although the semiconductor optical amplifier can extend the temperature range of satisfactory operation of the laser source by adding an overall gain function applied to the produced optical radiation, the integrated photonic circuit is still affected by the same temperature drift effects, thus having the same limitations as those presented with reference to [T0, T1]. Figure 1

[0014] In US2003 / 210723, the laser source and the optical amplifier are monolithically integrated, i.e. they share the same active area.

[0015] It is thus still desirable to extend the operating temperature range of the integrated photonic transmission circuit.

[0016] Object of the invention

[0017] ​​It is an object of the present invention to provide at least a partial solution to this problem. More specifically, it is an object of the present invention to provide an integrated photonic transmission circuit having a wider operating temperature range than prior art integrated circuits. SUMMARY

[0018] To achieve this object, the present invention proposes an integrated photonic transmission circuit according to claim 1.

[0019] According to other advantageous and non-limiting features of the present invention, alone or in any technically possible combination:

[0020] - the amplifying medium of the laser source and the amplifying medium of the amplifier are configured so that their respective photoluminescence wavelengths at the first temperature are separated by a wavelength interval less than or equal to the temperature drift of their respective photoluminescence wavelengths at the second temperature;

[0021] - the first amplifying medium is chosen so that, over the temperature range between the first temperature and the second temperature, the difference between the transmission wavelength and the first photoluminescence wavelength is less than half the bandwidth of the first amplifying medium;

[0022] - the integrated photonic transmission circuit comprises a plurality of laser sources having a first amplifying medium of the same composition, a plurality of semiconductor optical amplifiers having a second amplifying medium of the same composition, and a plurality of waveguides respectively arranged between the laser sources and the semiconductor optical amplifiers to respectively transmit the optical radiation produced by the laser sources to the semiconductor optical amplifiers;

[0023] - the integrated photonic transmission circuit comprises a plurality of complementary semiconductor optical amplifiers having a second complementary amplifying medium of the same composition and having a complementary photoluminescence wavelength less than or equal to the second photoluminescence wavelength at the first temperature;

[0024] - the integrated photonic transmission circuit comprises a plurality of optical switches optically downstream of the plurality of semiconductor optical amplifiers and of the plurality of complementary semiconductor optical amplifiers, each optical switch being connected to a semiconductor optical amplifier and to a complementary semiconductor optical amplifier;

[0025] - the integrated photonic transmission circuit comprises a plurality of laser sources and a plurality of semiconductor optical amplifiers each having an amplifying medium of the same composition, and a plurality of waveguides respectively arranged between the laser sources and the semiconductor optical amplifiers having an amplifying medium of different composition;

[0026] - the integrated photonic transmission circuit further comprises a wavelength multiplexer arranged downstream of the plurality of semiconductor optical amplifiers and optically connected to the semiconductor optical amplifiers to produce a multi-spectral optical radiation;

[0027] - the integrated photonic transmission circuit comprises at least one additional optical device arranged between the laser source and the semiconductor optical amplifier;

[0028] - Additional optical devices are modulators or switches. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features and advantages of the present invention will become apparent from the following detailed description of the invention with reference to the accompanying drawings, in which:

[0030] [ Figure 1 ]

[0031] [ Figure 1 ] shows the thermal drift phenomenon applied to integrated photonic transmission circuits and its effect on the optical radiation power generated by the circuit;

[0032] [ Figure 2a ]

[0033] [ Figure 2b ]

[0034] Figure 2a 、 Figure 2b A schematic diagram of an integrated photonic transmission circuit 1 according to an embodiment is shown in a top view;

[0035] [ Figure 3 ]

[0036] [ Figure 3 ] The gain and transmission wavelength L of the amplifying media A1 and A2 of the photonic circuit 1 configured according to the present invention are shown in the power / wavelength coordinate system. bragg Evolution with changes in circuit operating temperature;

[0037] [ Figure 4 ]

[0038] [ Figure 4 ] shows an integrated photonic transmission circuit in a parallel configuration;

[0039] [ Figure 5 ]

[0040] [ Figure 5 ] shows another example of an integrated photonic circuit in a parallel configuration;

[0041] [ Figure 6 ]

[0042] [ Figure 6 ] shows [ Figure 5 ] Operation of the photonic circuit shown;

[0043] [ Figure 7 ]

[0044] [ Figure 7An example of another embodiment of a photonic circuit according to the application in a serial configuration is shown. DETAILED DESCRIPTION

[0045] [ Figure 2a ] shows a schematic diagram of an integrated photonic transmission circuit 1 in a top view. The photonic circuit 1 comprises a laser source LS, a semiconductor optical amplifier SOA (more simply referred to as "amplifier" in the remainder of this document), and a waveguide WG monolithically integrated on a substrate, arranged between the laser source LS and the amplifier SOA.

[0046] The laser source LS comprises a first amplification medium Al. As already mentioned in the introduction of this application, this medium is formed by a stack of layers of III-V materials constituting at least one heterojunction, for example based on InP, AsGa, InGaAlAs, InGaAsP or InAsP. The first amplification medium Al here generally takes the form of a strip, arranged in alignment with a first coupling portion of the waveguide WG1, for example made of silicon, in which an optical mode is established when a first electric current flows through the first amplification medium Al. For the sake of simplicity, the schematic diagram in Figure 1 ] does not show the circuits, tracks and contacts for injecting this current.

[0047] The first amplification medium Al has a first photoluminescence wavelength L1 which depends on the composition of its active region and on its operating temperature. The active region can correspond to a quantum well based on a III-V quaternary compound (InGaAlAs, InGaAsP) or to a quantum dot based on InGaAs. The active region is sandwiched between a layer of N-type semiconductor material and a layer of P-type semiconductor material. These layers, generally based on InP or AsGa, enable the current to flow through the active region and electrically pump the amplification medium to achieve light generation.

[0048] The laser source also comprises a grating G, for example a Bragg grating, made in the first amplification medium Al or in the first waveguide portion WG1. The grating G defines, in particular through its pitch, the transmission wavelength L bragg .

[0049] Continuing the description of the schematic diagram in Figure 2a ], the amplifier SOA comprises a second amplification medium A2 having a second photoluminescence wavelength L gain . This second amplification medium A2 is different from the first amplification medium Al, i.e. it is composed of a stack of III-V materials having a different composition from the III-V materials constituting the first amplification medium Al. The second photoluminescence wavelength L gain is therefore different from the first photoluminescence wavelength L1.

[0050] The second amplifying medium A2 also takes the form of a section generally arranged in alignment with the second waveguide portion WG2 extending between the input and output of the amplifier and in which the optical mode generated by the laser source LS propagates and is amplified when the second medium A1 is traversed by the second current. For simplicity, [ Figure 1 ] does not show the circuits, traces, and contacts used to inject this current.

[0051] In any case, the first current flowing through the first amplifying medium A1 and the second current flowing through the second amplifying medium A2 are different from each other, and the two media are electrically isolated. Each of these media A1 and A2 is provided with contacts, traces, and circuits to control these currents and control the operation of the laser source and amplifier SOA independently of each other.

[0052] It should be noted that independently controlling the gain of the laser source and the gain of the amplifier SOA by injecting different currents therein is a significant advantage of the photonic circuit according to the present invention, since it provides the ability to adjust these gains as a function of temperature.

[0053] A passive waveguide WG is arranged between the laser source LS and the input of the amplifier SOA to transmit the optical radiation generated by the source LS to the amplifier SOA. It connects the first waveguide portion WG1 and the second waveguide portion WG2, so that they are not arranged end-to-end as in the prior art photonic circuit reported in the introduction of this application.

[0054] Note that the amplifying media A1 and A2 of the laser source LS and the amplifier SOA are distinct, electrically isolated, and made of materials of different compositions. Therefore, they cannot be continuous or comprised of a single, monolithic piece of material. Therefore, they are separated by a spacing distance d, necessitating the presence of a waveguide WG to propagate the optical mode from the laser source LS to the amplifier SOA.

[0055] Of course, the integrated photonic transmission circuit 1 may have other elements, for example, optically inserted between the laser source LS and the amplifier SOA via a plurality of waveguides GW. Figure 2b ] shows another type of photonic circuit 1, which comprises a modulator MOD, which is optically connected to a laser source LS and an amplifier SOA through a waveguide WG. Figure 2a and Figure 2b Also shown is an output waveguide WG3 optically connecting the amplifier output to components for coupling the light flow of the photonic circuit 1 to an optical fiber, for example. Other coupling configurations of the photonic circuit 1 are alternatively possible, for example via a surface grating coupled to the output waveguide WG3.

[0056] [ Figure 3] The gain and transmission wavelength L of the amplifying media A1 and A2 of the photonic circuit 1 configured according to the present invention are shown in the power / wavelength coordinate system. bragg Evolution with circuit operating temperature.

[0057] At a first relatively low operating temperature T0, which may correspond to room temperature (20°C), the transmission wavelength L bragg (T0) is located in the gain bandwidth of the first amplifying medium A1 and has a wavelength greater than the wavelength L1(T0) of the gain peak. This configuration is obtained by selecting the properties of the first amplifying medium A1 and defining the parameters of the grating of the laser source LS.

[0058] As an example, at a first temperature corresponding to room temperature (20°C), the transmission length L bragg is 1330 nm, and the photoluminescence wavelength L1 of the first amplifying medium A1 (the gain peak of the first medium) is selected to correspond to 1315 nm.

[0059] The gain bandwidth of the second amplifying medium A2 ( Figure 3 The thick line in FIG is configured to shift the gain bandwidth of the first amplifying medium A1 towards shorter wavelengths. However, it is advantageous to ensure that the amplifier SOA is "transparent", i.e., it is transparent at the transmission wavelength L of the laser source LS at the first temperature T0. bragg The gain at this position is not less than 0dB.

[0060] As an example, the photoluminescence wavelength L of the second amplifying medium A2 is gain (The gain peak of the second medium) is chosen to correspond to 1300 nm, ie 15 nm below the photoluminescence wavelength L1 of the first medium.

[0061] In this configuration at a first temperature T0, and as [ Figure 3 As can be clearly seen in FIG, the transmission wavelength is closer to the first photoluminescence wavelength L1 than to the second photoluminescence wavelength L gain .

[0062] The amplifier SOA contributes only slightly to the amplification of the optical mode generated by the laser source LS. The optical mode generated by the laser source LS alone has sufficient power, above a specified threshold, and requires little or no additional amplification.

[0063] As the operating temperature of the photonic circuit increases, the transmission wavelength L bragg and the first photoluminescence wavelength L1 and the second photoluminescence wavelength L gain Drift according to different dynamics.

[0064] Thus, at the second, relatively higher operating temperature T1, which can be 80°C or 100°C, the first photoluminescence wavelength L1 and the second photoluminescence wavelength L gain moves by a difference of the order of 0.6 nm per °C temperature rise (i.e. difference T1 - T0). The gain function of the first amplifying medium A1 and of the second amplifying medium A2 is also smaller at the second temperature T1 than at the first temperature T0. The transmission wavelength L bragg moves by about 0.1 nm per °C temperature rise (T1 - T0).

[0065] Continuing with the above example and taking the second temperature T2 as 80°C, which is 60° higher than the first temperature T0 chosen at room temperature, the transmission wavelength L bragg (T1 ) moves by 6 nm to 1336 nm, the first photoluminescence wavelength L1 and the second photoluminescence wavelength L gain move by 36 nm to 1351 nm and 1336 nm respectively.

[0066] Thus, and thanks to this differential temperature drift behavior, at the second operating temperature T1, the transmission wavelength L bragg (T1 ) is arranged in the gain bandwidth of the first amplifying medium A1, at a wavelength smaller than the wavelength of the gain peak L1 (T1 ). This transmission wavelength L bragg (T1 ) is also within the gain bandwidth of the second amplifying medium A2.

[0067] At the second temperature T1, the transmission wavelength L bragg is closer to the second photoluminescence wavelength L gain than to the first photoluminescence wavelength L1.

[0068] Thus, the amplifier SOA contributes to amplify the optical mode generated by the laser source LS. This amplification at least compensates for the lower gain of the amplifying media A1, A2 at the relatively higher temperature T1, so as to maintain the optical mode with sufficient power (above a determined threshold).

[0069] By distinguishing the two amplifying media A1, A2 of the laser source LS and of the amplifier SOA, and configuring them so that their photoluminescence wavelengths L1, L gain move by a wavelength difference smaller than or equal to their temperature drift within the target temperature range [T0-T1 ], it is possible to ensure that the optical mode generated by the laser source LS is sufficiently amplified by the first amplifying medium A1 of the laser source LS and / or by the second amplifying medium A2 of the amplifier SOA, so as to keep its power above a determined threshold within the extended target temperature range.

[0070] Advantageously, the first amplifying medium A1 is chosen so that, within the temperature range between the first temperature T0 and the second temperature T1, the transmission wavelength L braggThe deviation D from the first photoluminescence wavelength L1 is less than half of the bandwidth BW / 2 of the first amplification medium A1. This ensures that the power of the optical mode generated by the laser source is greater than the minimum power over the entire temperature range [TO-T1]. The bandwidth BW of the first amplification medium A1 can be set as usual, for example, to 3 dB.

[0071] The first temperature TO can be the ambient temperature and the second temperature can be 60°C, 80°C or 100°C, depending on the target operating range for which the photonic circuit 1 is intended.

[0072] The above principles of the application can be deployed in many different ways.

[0073] Thus, Figure 4 An integrated photonic transmission circuit 1 is shown in a parallel configuration. The circuit comprises a plurality of identical laser sources LS. These laser sources LS each comprise a grating defining the same transmission wavelength L bragg . They also each comprise a first amplification medium A1, all of these amplification media A1 having the same composition and thus defining the same first photoluminescence wavelength L1. Advantageously, this medium is derived from a single monolithic segment of III-V material formed at right angles to a plurality of first waveguide portions WG1 and structured to define a plurality of laser sources LS therein, as set out in the introduction to this application.

[0074] The photonic circuit 1 also comprises a plurality of semiconductor optical amplifiers SOA, each comprising a second amplification medium A2 having the same composition and thus defining the same second photoluminescence wavelength L gain . Advantageously, and as explained in the case of the first amplification medium A1, the second medium A2 is derived from a single monolithic segment of III-V material formed and structured at right angles to a plurality of second waveguide portions WG2.

[0075] Finally, the photonic circuit 1 comprises a plurality of waveguides WG, WG' arranged between the laser sources LS and the semiconductor optical amplifiers SOA to respectively send the optical radiation generated by the laser sources LS to the semiconductor optical amplifiers SOA. In the embodiment shown in Figure 4 ] a modulator MOD is also respectively provided between the laser source LS and the amplifier SOA to form an integrated photonic transmission circuit, but this element is entirely optional or can be replaced with an optical element providing another function.

[0076] The properties of the amplification media A1, A2 and the transmission wavelength L bragg are chosen in accordance with what is presented in the description of the previous figures: very generally, at the first temperature TO, the transmission wavelength L bragg is greater than the second photoluminescence wavelength L gaincloser to the first photoluminescence wavelength L1. At a second temperature T1 higher than the first temperature T0, the transmission wavelength L bragg closer to the second photoluminescence wavelength L gain .

[0077] [ Figure 5 ] shows another embodiment of the photonic circuit 1 in a parallel configuration.

[0078] This Figure 5 photonic circuit has a plurality of laser sources LS and modulators MOD with the same configuration as in Figure 4 . Each laser source LS is optically connected to the input of a modulator MOD via a waveguide WG. The output channels of the modulators MOD are connected to semiconductor optical amplifiers SOA with the same second amplification medium A2, respectively, via further waveguides WG'. These elements are configured in the same way as in the configuration of the embodiment of Figure 4 .

[0079] Advantageously, the modulators MOD each have two anti-phase outputs. This can be a Mach-Zehnder type silicon modulator. Alternatively, the modulators can be replaced by simple switches, which also have two outputs to which the energy of the optical radiation propagating from their input is distributed.

[0080] In the case of the integrated circuit shown in Figure 5 , the second outputs (not connected to the semiconductor optical amplifiers SOA) are optically connected to a plurality of complementary semiconductor optical amplifiers SOA2 via waveguides WG'. These complementary amplifiers SOA2 have the same complementary amplification medium A2', which is different from the second amplification medium A2. More specifically, the complementary amplification medium A2' has a complementary photoluminescence wavelength L gain less than or equal to the second photoluminescence wavelength L gain2 .

[0081] As shown in Figure 6 , this configuration of the photonic circuit extends the operating temperature range of the photonic circuit, the complementary amplifiers SOA2 amplifying the optical modes when the temperature drift no longer allows the amplifiers SOA to provide sufficient gain.

[0082] Downstream of the amplifiers SOA and the complementary amplifiers SOA2, a plurality of optical switches SW are provided for selecting from among the plurality of outputs of the amplifiers SOA and the complementary amplifiers SOA2 and, depending on the effective operating temperature of the circuit 1, selecting the amplified radiation that propagates to the transmission output of the integrated photonic circuit 1 through an output waveguide WG3.

[0083] More specifically, at relatively low temperatures, the switch is operated to propagate radiation from the amplifier SOA to the output waveguide WG3. At relatively high temperatures, the switch is operated to propagate radiation from the complementary amplifier SOA2 to the output waveguide WG3.

[0084] [ Figure 7 ] shows yet another example of an embodiment of a photonic circuit 1 according to the application, this time in a so-called wavelength division multiplexed configuration.

[0085] In this configuration, the plurality of laser sources LSI-LS5 and the plurality of semiconductor optical amplifiers SOA1-SOA5 each comprise amplifying media A'1-A'5 of identical constitution. In other words, the single-component amplifying media A i are placed in alignment with the first waveguide portions of the laser sources LS i and with the second waveguide portions of the amplifiers SOA i . The plurality of waveguides WG, WG' are arranged between the laser sources LS i and the optical amplifiers SOA i+1 , the first amplifying media A i of the laser sources LS i having a different composition than the second amplifying media A i+1 of the optical amplifiers SOA i+1 to respectively transmit the optical radiation generated by the laser sources LS i to the semiconductor optical amplifiers SOA i+1 .

[0086] In the example shown, the photonic circuit comprises 5 types of amplifying media A'1-A'5, each derived from a portion of III-V material formed and structured in alignment with the first waveguide portions of the laser sources LS and the second waveguide portions of the amplifiers SOA. The laser sources LS i are also equipped with gratings defining a transmission wavelength L bragg,i . The amplifying media A 'i and the properties of the transmission wavelength L bragg,i are thus selected so that the laser sources LS i and the amplifiers SOA1 are able to function correctly.

[0087] The circuit shown has a plurality of laser sources LS i , each having a different transmission wavelength L bragg_i , and a plurality of amplifiers SOA i . The transmission wavelengths L bragg,1 - L bragg,5 are staggered (as Figure 7], respectively 1330 nm, 1310 nm, 1290 nm, 1245 nm, 1270 nm, and 1225 nm), to provide multiple light beams that can be combined or wavelength-multiplexed to form multi-wavelength radiation at the output of the photonic circuit 1. The materials of the amplifying media A'1-A'5 are selected to uniformly stagger their photoluminescence wavelengths (1305 nm, 1285 nm, 1265 nm, 1245 nm, and 1225 nm).

[0088] like[ Figure 7 ] As shown, a waveguide WG is used to include a first amplifying medium A' having a first photoluminescent wavelength. i The laser source LS is optically coupled to a second amplifying medium A' comprising a second photoluminescence wavelength i+1 amplifier SOA.

[0089] This link is repeated through the waveguides WG, WG' to connect the first amplifying medium A i Associated laser source LS i coupled to the second amplifying medium A i+1 Associated amplifier SOA i+1 , the second amplifying medium is different from the first amplifying medium.

[0090] Please note that in [ Figure 7 In the chain shown in FIG. 1 , the first amplifier SOA1 (associated with the amplifying medium designated A′1 in the figure) and the last laser source LS5 (associated with the amplifying medium designated A′5 in the figure) of the chain are not used. Since these two elements are not utilized, they can be omitted.

[0091] The advantage of this wavelength multiplexing implementation is that it limits the number of different components (segments) of amplification media used to make the optical device by combining them. Figure 7 The structure shown requires 5 segments of different types that are constructed to create the same laser beams as the 4 laser sources LS i and 4 amplifier SOA i The associated first amplifying medium and the associated second amplifying medium, that is, 8 amplifying media.

[0092] Of course, the invention is not limited to the embodiments described and alternative embodiments can be added without departing from the scope of the invention as defined by the claims.

Claims

1. An integrated photon transmission circuit (1), comprising: - a laser source (LS) for generating optical radiation and comprising a defined transmission wavelength (L bragg ) and a first amplifying medium (A1) having a first photoluminescent wavelength (L1); a semiconductor optical amplifier (SOA) comprising a second amplifying medium (A2) electrically isolated from the first amplifying medium (A1) and separated from the first amplifying medium (A1) by a separation distance (d), The semiconductor optical amplifier (SOA) has a second photoluminescence wavelength (L gain ); at least one passive waveguide (WG) arranged between the laser source (LS) and the semiconductor optical amplifier (SOA) to transmit the optical radiation generated by the laser source (LS) to the semiconductor optical amplifier (SOA); The laser source (LS) and the semiconductor optical amplifier (SOA) are configured such that: i. At the first temperature (T0) of 20°C, the transmission wavelength (L bragg ) than the second photoluminescence wavelength (L gain ) is closer to the first photoluminescence wavelength (L1), and ii. At the second temperature (T1) of 80°C, the transmission wavelength (L bragg ) is closer to the second photoluminescence wavelength (L ) than the first photoluminescence wavelength (L1) gain ).

2. The integrated photonic transmission circuit (1) according to claim 1, wherein the amplifying medium (A1) of the laser source (LS) and the amplifying medium (A2) of the amplifier (SOA) are configured so that their respective photoluminescence wavelengths (L1, L2) at the first temperature (T0) of 20°C are gain ) are separated by a wavelength interval that is less than or equal to their temperature drift at the second temperature (T2).

3. The integrated photonic transmission circuit (1) according to one of the preceding claims, wherein the first amplifying medium (A1) is selected such that in the temperature range between the first temperature (T0) of 20°C and the second temperature (T1), the transmission wavelength (L bragg ) and the first photoluminescence wavelength (L1) is less than half the bandwidth of the first amplifying medium (A1).

4. The integrated photonic transmission circuit (1) according to claim 1, comprising a plurality of laser sources (LS) having a first amplifying medium (A1) of the same composition, a plurality of semiconductor optical amplifiers (SOAs) having a second amplifying medium (A2) of the same composition, and a plurality of waveguides respectively arranged between the laser sources (LS) and the semiconductor optical amplifiers (SOAs) for respectively transmitting the optical radiation generated by the laser sources (LS) to the semiconductor optical amplifiers (SOAs).

5. The integrated photonic transmission circuit (1) according to claim 4, comprising a plurality of complementary semiconductor optical amplifiers (SOA2), the plurality of complementary semiconductor optical amplifiers having a second complementary amplifying medium (A2') of the same composition and having a wavelength less than or equal to the second photoluminescence wavelength (L2) at the first temperature (T0) of 20°C. gain ) of the complementary photoluminescence wavelength (L gain2 ).

6. The integrated photonic transmission circuit (1) according to the preceding claim, comprising a plurality of optical switches (SW) optically downstream of the plurality of semiconductor optical amplifiers (SOAs) and the plurality of complementary semiconductor optical amplifiers (SOAs2), each optical switch being connected to a semiconductor optical amplifier (SOA) and a complementary semiconductor optical amplifier (SOA2).

7. The integrated photonic transmission circuit (1) according to one of claims 1 to 3, comprising: Multiple laser sources (LS i ) and multiple semiconductor optical amplifiers (SOAs i ), the laser source and the semiconductor optical amplifier (LS i , SOA i ) each having the same composition of the amplifying medium; and laser sources (LS i ) and semiconductor optical amplifiers (SOAs) i+1 ) between multiple waveguides (WG, WG').

8. The integrated photonic transmission circuit (1) according to the preceding claim, further comprising a wavelength multiplexer (MUX) arranged between the plurality of semiconductor optical amplifiers (SOAs) i ) downstream and optically connected to the semiconductor optical amplifier (SOA i ) to produce multi-spectral light radiation.

9. The integrated photonic transmission circuit (1) according to one of the preceding claims, comprising at least one additional optical device arranged between the laser source (LS) and the semiconductor optical amplifier (SOA).

10. The integrated photonic transmitter circuit (1) according to the preceding claim, wherein the additional optical device is a modulator (MOD) or a switch.

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