RU8172U1 - SEMICONDUCTOR LASER CONTROL DEVICE - Google Patents

Abstract

A semiconductor laser control device containing a serially connected input pulse former, the information input of which is the information input of the device, a modulating current source and a current adder, the output of which serves to connect the input of a semiconductor laser, and the second input of the current adder is connected to the output of the bias current source, the output detector laser radiation, the optical input of which serves to connect the output of a semiconductor laser, the first and second threshold blocks, characterized in that the first, second and third pulse shapers, the first, second, third and fourth I elements, the first and second delay elements, the first and second integrators, the outputs of which are respectively connected to the control input of the modulating current source and the input of the bias source, are introduced into it , the inputs of the threshold blocks are combined and connected to the output of the laser output radiation detector, the outputs of the first and second threshold blocks are respectively connected to the information inputs of the first and second impulse drivers LSS, the output of the input pulse shaper through the first delay element is connected to the information input of the third pulse shaper, the gate inputs of the first, second, and third pulse shapers are combined and through the second delay element are connected to the gate input of the input pulse shaper, which is the gate input of the device, the inverse outputs of the first and the second pulse shapers are connected respectively to the first inputs of the first and third elements And, the direct outputs of the first and

Description

Semiconductor Laser Control

The proposed utility model relates to a technique for controlling semiconductor laser tubes and can be used in the easiest paths when transmitting digital signals via fiber-optic cable, as well as in open optical transmission systems.

A lime stabilization scheme for the output power of a floor laser laser (see Application of Yaionii No. 61-46994, M.cl. H01S 3/133, publ. 16.10.86), containing a source of modulating current, which converts the input digital signal into imgumsy current, supplied to the laser, supply a bias current that generates a constant current from the mixed laser, a photodetector with a direct current amplifier, which is a laser output detector, a peak value detector, an average value detector., the first threshold unit that compares the peak value of the signal with a photodetector with a reference value, and a second threshold block that compares the average signal value with a reference value, while the first threshold block is etched by the modulating current source, and the second threshold block is etched by the bias current source.

The known scheme does not provide independent adjustment of the radiation powers. Corresponding to the transmitted logical unit and zero. The ratio of these capacities is 11 the extinction coefficient normalized for modern fiber-optic transmission systems (VOSN). In addition, this scheme is not applicable for VOSN with a flashing constant component, for example, for VOSN using packet communication.

Closest to the inventive device for the lettering of a semiconductor laser is a circuit for a semiconductor laser (see European application L20497270 M.cl. H01S 3/133, H01S 3/103, publ. 28.01.92). It contains a serially connected input pulse former, a source of current current mode and a current adder, the output of which serves to connect the input of a semiconductor laser, and the second input of the current adder is connected to the output of the bias current source, a laser output radiation detector, whose optical input serves to connect the output semiconductor laser, to the output of the output laser radiation detector connected in series are the peak peak detector and the first threshold block, the output which is connected to the control input of current source -liruyuschego modes, and connected in series iikovy minimum level detector and a second threshold unit, whose output is connected to the output of the bias current source. This pickling circuit provides independent adjustment of the maximum and minimum values of the output power by adjusting the response thresholds of the first and second threshold blocks. However, the accuracy of maintaining the maximum and minimum output power corresponding to the transmission of logical units and zero is low due to the low accuracy of the peak detectors. In addition, this scheme does not work well in VOSN with a fluctuating DC component, for example, in VOSN used for packet communication.

The task of the useful model is to increase the accuracy of etching by the output power of a semiconductor laser.

The solution to this problem is provided in a control device for a half-wire laser containing a pulse input shaper connected in series. the information input of which is the information input of the device, the modulating current source and the current adder, the output of which serves to connect the input of a semiconductor laser, and the second input of the current adder is connected to the output of the bias current source, a laser output radiation detector, whose optical input is used to connect the output of a semiconductor laser , the first and second threshold blocks, characterized in that the first, second and third formers are introduced into it.

the first, second, third and fourth elements of And, the first and second delay elements, the first and second integrators, the outputs of which are respectively connected to the input of the modulating current source and the input of the biased source 11J, the inputs of the threshold blocks are combined and connected to the output of the laser output radiation detector, the outputs of the first and second threshold blocks, respectively, are connected to the information inputs of the first and second impulse drivers, the output of the input pulse former through the first delay element is connected n with the information input of the third pulse shaper, the gate inputs of the first, second and third pulse shapers are combined and connected through the second delay element to the gate input of the input pulse shaper, which is the gate input of the device, the inverse outputs of the first and second pulse shapers are connected respectively to the first inputs the first and third elements And, the direct outputs of the first and second shapers of the implls are connected respectively to the first inputs of the second and the fourth elements of And, the second inputs of the first and second elements of And are combined and connected directly to the output of the third pulse shaper, and the second inputs of the third and fourth elements of And - with the inverse output of the third driver of the pulses, the outputs of the first and second elements And are connected respectively to direct and inverse inputs of the first integrator, and the outputs of the third and fourth elements AND are connected respectively with direct and inverse inputs of the second integrator.

The introduction into the device of three pulse shapers, four pulsed AND elements, two delay elements, as well as the implementation of integrators with paraphase inputs, provides double selective processing of the signal at the output of the laser output radiation detector. As a result of this, the bias current of the laser is regulated only when logical nulls are input to the device by counting the number of excesses and not exceeding the minimum level of the output signal of the laser output detector of the threshold level of the second threshold block at times corresponding to the maximum signal-to-noise ratio. The current mode of the laser1P1 laser is regulated only when a logical unit arrives at the unit of counting the number of excesses and not exceeded by the maximum level of the output signal of the laser output detector of the threshold level of the first threshold block at time instants corresponding to the maximum signal to noise ratio. The proposed device is illustrated by drawings, where in FIG. 1 is a structural diagram of a semiconductor laser control, and FIG. 2 is a temporary dnafamma explaining the operation of the device. In FIG. 1 shows the input pulse shaper 1 sequentially connected, the modulating current source 2 and the current adder 3, the bias current source 4, the semiconductor laser 5, the output laser radiation detector 6, the first and second threshold blocks 7 and 8, the first, second, and third shapers respectively, 9-11 pulses, the first, second, third and fourth elements And, respectively, 12-15, the first and second integrators 16 and 17, the first and second delay elements 18 and 19. The optical input of the detector 6 of the output laser is connected to the output of the laser 5, the output of the detector 6 of the output laser radiation is connected to the inputs of the norm blocks 7 and 8, the outputs of which are respectively connected to the information inputs of the first and second drivers 9 and 10 pulses, the output of the input driver 1 pulse the first delay element 18 is connected to the information input of the third pulse shaper 11, strobing the inputs of the first, second and third shaper, respectively, 9-11 impulses are connected through the second element t 19 delays are connected to the gate input of the input pulse shaper 1, which is the gate input of the device. The inverse outputs of the first and second shapers 9, 10 implls are connected respectively to the first inputs of the first and third elements And 12.14. Direct outputs of the first and second shapers 9.10 pulses are connected respectively with the first inputs of the second and fourth elements And 13.15. The second inputs of the first and second elements And 12,13 are connected to the direct output of the third driver 11 imshls, and the second inputs of the third and fourth elements And 14,15 with the inverse output of the third driver 11. The outputs of the first and second elements And 12,13 are connected respectively with direct and inverse inputs of the first integrator 16. the output of which is connected to the control input of the source 2 of the modulating current. The outputs of the third and fourth elements And 14.15 are connected respectively to the direct and horizontal inputs of the second integrator 17, the output of which through the source 4 of the mixture is connected to the second input of the adder 3 current. The operation of the proposed semiconductor laser control device can be explained using FIG. 2 as follows. The device has a trace only one after another of the operating modes: the mode of heating from the moment of switching on to setting the nominal bias current of the laser, the mode of setting the current laser mode according to the preamble of the transmitted signal, the transmission mode of the information packet, and the standby mode of the next packet. In the above time diagrams (Fig. 2), the moment of switching on the device corresponds to the left time moment. Let the signal in the NRZ format (Fig. 2a), which is equal to (the heating mode) during the first six clock cycles, and then a sequence of five alternating units and zeros that form the preambles (modulation current mode setting mode) be received at the input of the input pulse shaper 1 laser according to the preamble). At the gateway input of the device, and hence the gateway input of the input shaper 1 of the impls receives a clock signal (fig.2b). The input shaper 1 of the impls performs the regeneration of the input signal (pigv). At the initial moment of time, the laser bias current 1c is zero (Fig. 2d), which corresponds to the left output laser 5 and the output voltage of the laser output detector 6 is less than the threshold of the second and threshold unit 8, equal to Uo (Fig. 2), therefore, inverse the output of the second pulse former arises a signal of logical unity (Fig.2p) synchronously with the delayed clock signal (Fig.2g). This signal is sent to the first input of the third element 14 I. The logic level signal from the direct output of the second pulse generator 10 (FIG. 2p) is fed to the first input of the fourth element 15 I. At the same time, the signal of the logical unit from the inverse output of the third pulse generator 14 is fed to the second the inputs of the third and fourth elements 14 and 15 And (fig.2i), resulting in the output of the third element 14 And the signal takes the value of a logical unit (Fig. 2C), and at the output of the fourth element 15 And the signal is equal (Fig.2t). The voltage at the output of the second integrator 17 is reduced (Fig.2u). As a result, the bias current of the laser 5 is increased (Fig. 2d). The first and second elements 12 and 13 And are locked by a logic zero voltage, which goes to the second inputs of these elements from the direct input of the third one, to the second inputs. 11th 11img1 ls (Fig.2h), and the voltage at the output of the first integrator 16 remains unchanged at the following clock intervals of the laser bias current 1 s will increase until its value reaches the threshold value of 1 °, corresponding to the minimum level of power P0 of the laser radiation. In this case, the signal at the output of the output radiation detector 6 will exceed the threshold of the second threshold unit 8, equal to Uo, as a result of which it will switch and synchronously with the delayed clock signal (Fig.2g), the second pulse shaper 10 will switch, resulting in a signal at the output of the third element 14 And will take a value of logical zero (figs). and the signal at the output of the fourth element 15 And - a logical unit (Fig. 2T). The voltage at the output of the second integrator 17 will decrease, which will lead to a decrease in the bias current of the laser. When the logic unit signals are fed to the information input of the device, the modulating current source is turned on (Fig.2d). The logic zero signal at the inverse output of the third pulse shaper 11 zaps the third and fourth elements 14 and 15 And the voltage at the output of the second integrator 17 does not change (Fig. 2y). The signal of a logical unit at the direct output of the third pulse shaper 11 unlocks the first and second elements 12 and 13 I. If the current 1 m of laser modulation does not exceed the threshold

И value, then the laser output power does not exceed the maximum radiation power P1 and, accordingly, the voltage at the output of the output radiation detector b does not exceed the response threshold of the first threshold block 7. equal to U1 (Fig. 2e). The signal level of the logical unit at the inverse output of the first driver 9 pulses synchronously with the delayed pulses of the clock frequency (Fig.2g) opens the first element 12 And, as a result, the voltage at the output of the first 11 integrator 16 will increase (Fig.2o) and increase the current 1m laser modulation ( fig.2d). The voltage at the output of the first integrator 16 will increase until the amplitude 1y of the modulation current Im exceeds the threshold value II, corresponding to the maximum power level P1 of the laser radiation. When the amylit-dy current of the modulation current Im exceeds a threshold value of 1 °, the voltage at the output of the detector 6 of the output laser radiation (Fig. 2e) exceeds the threshold of the first threshold unit, equal to U1, and the second 13 And element opens and the voltage at the output of the first integrator 16 decreases. Thus, the second integrator 17 compares the number of higher-than-frequency pulses and does not exceed the minimum level of the output signal of the laser output detector 6 of the threshold level of the second threshold block 8 at time instants corresponding to the maximum signal / noise ratio and regulates the laser bias current 1 s as follows. so that the number of overshoots and non-overshoots in the steady state are equal to drlt drig Similarly, the first integrator 16 compares the number of times n11 exceeded by the maximum level of the output signal of the laser detector 6 of the output level of the threshold level of the first threshold unit 7 at times corresponding to the maximum signal to noise ratio and current 1m of laser modulation so that the number of excesses and not exceeded in the steady state are equal to each other. In steady state, the minimum output power level Po will be determined by the threshold of the second threshold block 8, and the maximum output power level P1 will be determined by the threshold of the first threshold block 7. The stability of the laser output power levels will be determined by the stability of the threshold characteristics of threshold blocks 7 and 8 and the stability of the transfer characteristics of the detector 6 of the output laser radiation.

An example of the execution of the device blocks, for example, for FOTS with a hierarchical hierarchy with a transmission speed of 155.52 Mbit / s, can be explained as follows. The input pulse shaper 1, the first, second and third shapers 9-11, respectively, can be performed on K1500TM131 microcircuits, each of which consists of three D triggers of the MS type (see Application of integrated microcircuits in electronic computer technology: Reference / R.V.Danilov S.A. Yeltsova, Yu.P. Ivanov et al .; Edited by B.N. Fayzulaev, B.V. Tarabrin -M .: Radio and communications, 1986.-348с .: ill.) Source 2 modulating current is made on 2T648 transistors according to the scheme of a differential amplifier with a regulated transistor current generator in a current-setting circuits, and the bias current source 4 is made on a KT815 transistor (see Poltchtrovodshoshovye devices. Transistors of medium and high power: Sgrafochnik - 2nd ed., stereotype. A.A. Zaitsev, A.I. Mirkin, V.V. Mokryaev and others .: Under the editorship of A.V. Golomedov. M.: Rad1yu and KUBK-a connection 1994- 640 p. With ill.). The detector 6 of the laser output radiation can be performed on a feedback photodiode located in the housing of the used injection-tube and conductive laser ILPN-206-1 (see the Catalog of Products Presented at the Domestic Market of Components of Fiber Optic Transmission Systems, Mosca, 1992.1- 92), and on the K171UV2 microcircuit, which is a broadband amplifier with differential input and output (see Radio receivers VN Bankov. L.G. Barulin, M.I. Zhodzinsky and others: Under the editorship of L.G. Barulina.-M: Radio and communications, 1984.- 272 p., Ill. - (Projected s on integrated electronic agsharatury M1zhroskhemah)). The first and second threshold blocks 7 and 8 are made on KR597CA4 microcircuits, which are an improved version of the voltage comparator KR597CA1 (see Application of precision analog microcircuits / A.G. Aleksenko, E.A. Kolombet, G.I. Starodub. - 2nd ed. and add. - M .: Radio and communications, 1985. - 304 p., ill.). brain teaser

elements 12-15 And can be performed on K1500LM102 microcircuits, which consist of ZI / ZI-NOT elements (see Application of integrated microcircuits in electronic computer technology: Reference book / R.V.Danilov, S.A. Eltsova, Yu.P Ivanov et al .; iodine, ed. B.N. Fayzulaev, B.V. Tarabrina -M .: Radio and communications, 1986.-348с .: silt). Integrators can be performed on operational amplifiers of the K140UD7 type (see. Application of precision analog microcircuits / A.G. Aleksenko, E.A. Kolombet, G.I. Starod B.- 2nd ed. Revised and enlarged. - M .: Radio and communication, 1985. - 304 p., ill.). Delay elements can be performed on series-connected differential receivers that are part of the K1500LM102 microcircuit (see. Application of integrated circuits in electronic computer technology: Reference Book / R.V.Daiilov, S.A. Eltsova. Yu.P. Ivanov et al .; Edited by B.N. Fayzulaev and B.V. Tarabrin-M .: Rad1yu and Svyaz. 1986.-348с .: silt).

Claims (1)

A semiconductor laser control device containing a serially connected input pulse former, the information input of which is the information input of the device, a modulating current source and a current adder, the output of which serves to connect the input of a semiconductor laser, and the second input of the current adder is connected to the output of the bias current source, the output detector laser radiation, the optical input of which serves to connect the output of a semiconductor laser, the first and second threshold blocks, characterized in that the first, second and third pulse shapers, the first, second, third and fourth I elements, the first and second delay elements, the first and second integrators, the outputs of which are respectively connected to the control input of the modulating current source and the input of the bias source, are introduced into it , the inputs of the threshold blocks are combined and connected to the output of the laser output radiation detector, the outputs of the first and second threshold blocks are respectively connected to the information inputs of the first and second impu LSS, the output of the input pulse shaper through the first delay element is connected to the information input of the third pulse shaper, the gate inputs of the first, second, and third pulse shapers are combined and through the second delay element are connected to the gate input of the input pulse shaper, which is the gate input of the device, the inverse outputs of the first and the second pulse shapers are connected respectively to the first inputs of the first and third elements And, the direct outputs of the first and The second pulse shapers are connected respectively to the first inputs of the second and fourth elements And, the second inputs of the first and second elements And are combined and connected to the direct output of the third pulse shaper, and the second inputs of the third and fourth elements And with the inverse output of the third pulse shaper, the outputs of the first and second And elements are connected respectively with direct and inverse inputs of the first integrator, and the outputs of the third and fourth elements And are connected respectively with direct and inverse inputs second integrator.