CN201435793Y

CN201435793Y - Optical signal monitoring circuit of GPON ONU module

Info

Publication number: CN201435793Y
Application number: CN2009201336828U
Authority: CN
Inventors: 王侃; 吴春付
Original assignee: Shenzhen Neo Photonic Technology Co Ltd
Current assignee: Shenzhen Apat Optoelectronics Components Co., Ltd.
Priority date: 2009-07-17
Filing date: 2009-07-17
Publication date: 2010-03-31
Anticipated expiration: 2019-07-17

Abstract

The utility model provides an optical signal monitoring circuit of a GPON ONU module, which comprises a sampling resistor, a sampling signal processing circuit, a signal comparator and a feedback circuit. The sampling circuit is connected between a positive electrode of a laser monitoring PD and an MD pin of a laser driving circuit, laser backlight current is converted into a voltage difference signal inputted to the sampling signal processing circuit, after being processed, the voltage difference signal forms a comparison voltage difference signal inputted to the signal comparator, an outputend of the signal comparator is connected with a transmitting signal monitoring port TX-SD of a system board, and the feedback circuit is connected between the output end and the input end of the signal comparator. Because the feedback circuit is connected between the output end and the input end of the signal comparator, input level of the signal comparator can be real-time adjusted, thereby achieving the purpose of effectively tracking optical signals in a large range. Each ONU has capacity of real-time monitoring luminous states of respective optical modules.

Description

The optical monitoring signal circuit of GPON ONU module

Technical field

The utility model relates to the ONU optical module of a kind of gigabit passive optical network GPON (Gigabit Passive OpticalNetwork) system, relates in particular to the optical monitoring signal circuit of GPON ONU module.

Background technology

Optical fiber inserts the preferred manner that becomes access network construction in the world gradually, and the passive optical network PON technology becomes the highest technical scheme of cost performance especially in the Optical Access Network construction.Passive optical network technique relies on its time division multiplexing transmission means up, that broadcast type is descending to make the bandwidth applications rate of optical-fiber network higher.Each terminal ONU is finished registration in the PON system after, local side OLT can distribute a time slot for each ONU, only allow each ONU with its time slot corresponding in to OLT emission light signal, all the other times then are in off state, in whole communication process, in arbitrary time slot, local side OLT can only receive uploading signal and it being handled of an ONU, uploads light signal and can not accept plural ONU simultaneously.Otherwise, when a certain terminal ONU breaks down, no longer be subjected to the control of local side OLT, be in continuous luminance (so-called " rogue ONU ") always, will cause OLT work schedule confusion, other ONU in the system can't finish normal data transfer with OLT.ONU optical module does not at a high speed have the optical monitoring signal function at present, can not report luminance to OLT.

Summary of the invention

For overcoming above shortcoming, the utility model provides a kind of optical monitoring signal circuit that reports the GPON ONU module of luminance in real time to system that has.

For reaching above goal of the invention, the utility model provides a kind of optical monitoring signal circuit of GPON ONU module, comprise: a sampling resistor, one sampled signal treatment circuit, one signal comparator and a feedback circuit, described sampling resistor is connected in laser and monitors between the MD pin of the positive pole of PD and drive circuit for laser, convert the laser back facet current to voltage differential signal and input to described sampled signal treatment circuit, form real-time and effective comparative voltage difference signal after treatment and input to signal comparator, the output connected system plate of this signal comparator monitoring port TX-SD that transmits, described feedback circuit is connected between the output and input of described signal comparator.

Described sampled signal treatment circuit comprises: first divider resistance, second divider resistance, the 3rd divider resistance, the 4th divider resistance, the 5th divider resistance, first end of first divider resistance is connected with the positive pole that monitors PD, and its second end is electrically connected second divider resistance of an end ground connection and the positive input of signal comparator; First end of the 3rd divider resistance is with after described MD pin is connected, and the other end divides three branch roads to connect: first branch road is electrically connected the 4th divider resistance of an end ground connection; Second branch road is electrically connected the 5th divider resistance that an end connects power supply VCC; The 3rd branch road is electrically connected the reverse input end of signal comparator.

Described feedback circuit comprises the 6th divider resistance and a N-MOS transistor, and the 6th divider resistance one end is electrically connected with N-MOS transistor drain D, and the other end is electrically connected with the reverse input end of signal comparator; The transistorized grid G of N-MOS is electrically connected with the output of signal comparator; The transistorized source S ground connection of N-MOS.

Described feedback circuit comprises the 6th divider resistance and an analog switch, the 6th divider resistance one end is electrically connected with the input of analog switch, the other end is electrically connected with the reverse input end of signal comparator, the output of signal comparator is electrically connected the control end of analog switch, this analoging switch output end ground connection.

Described feedback circuit is the 7th divider resistance, is connected between the output and positive input of described signal comparator.

The general value of described sampling resistor is 1K Ω～2K Ω.

In the above-mentioned optical monitoring signal circuit, because feedback circuit is connected in the input of described signal comparator and connected system plate and transmits between the output of monitoring port TX-SD, can adjust the incoming level of signal comparator in real time, reach effective tracking of light signal on a large scale, therefore, each ONU has the real-time monitoring ability of optical module luminance separately, guarantees that it can report the ONU optical module whether to be in normal luminance and can report the ONU optical module whether to be in off state to system in invalid luminous time slot in effective luminous time slot to system.

Description of drawings

Fig. 1 represents the optical monitoring signal circuit frame principle figure of the utility model GPON ONU module;

Fig. 2 represents negative feedback optical monitoring signal circuit working schematic diagram shown in Figure 1.

Fig. 3 represents positive feedback formula optical monitoring signal circuit working schematic diagram shown in Figure 1.

Embodiment

Figure below is in conjunction with describing the utility model most preferred embodiment in detail.

The optical monitoring signal circuit of GPON ONU module as shown in Figure 1, comprise: a sampling resistor 10, one sampled signal treatment circuit 20, one signal comparator 30 and a feedback circuit 40, described sampling resistor 10 is connected in laser and monitors between the MD pin of the positive pole of PD and drive circuit for laser, convert the laser back facet current to voltage differential signal and input to described sampled signal treatment circuit 20, form real-time and effective comparative voltage difference signal after treatment and input to signal comparator 30, the output connected system plate of this signal comparator monitoring port TX-SD that transmits, feedback circuit 40 is connected between the output and input of signal comparator 30, so that adjust the incoming level of signal comparator 30 in real time, reach effective tracking of light signal on a large scale.The diode PD backlight of LD is connected to by sampling resistor 10 on the MD pin of laser driver, and the level of MD pin enables (BEN) signal with burst to be changed, and when the Output optical power of LD is big more, MD pin level is high more; Enable to turn-off under (BEN OFF) situation when module is in, MD pin level is determined by external circuit.Choosing of sampling resistor 10 is comparatively crucial, be to choose resistance to be the bigger the better in principle, but resistance is crossed conference the registration process of ONU optical module in system is impacted, and makes the luminous signal long period could the recovery amplitude, and the general value of sampling resistor 10 is 1K Ω～2K Ω.

Negative feedback optical monitoring signal circuit as shown in Figure 2, the signal that comprise sampling resistor 10, sampled signal treatment circuit 20, has forward and a reverse input end relatively 30 and feedback circuit 40.Sampled signal treatment circuit 20 comprises: first divider resistance 21, second divider resistance 22, the 3rd divider resistance 23, the 4th divider resistance 24, the 5th divider resistance 25, first end of first divider resistance 21 is connected with the positive pole that monitors PD, and its second end is electrically connected second divider resistance 22 of an end ground connection and the positive input of signal comparator 30; First end of the 3rd divider resistance 23 is with after the MD pin of laser driver is connected, and the other end divides three branch roads to connect: first branch road is electrically connected the 4th divider resistance 24 of an end ground connection; Second branch road is electrically connected the 5th divider resistance 25 that an end connects power supply VCC; The 3rd branch road is electrically connected the reverse input end of signal comparator 30.Feedback circuit 40 comprises that the 6th divider resistance 41 and a N-MOS transistor 42, the six divider resistances 41 1 ends are electrically connected with the drain D of N-MOS transistor 42, and the other end is electrically connected with the reverse input end of signal comparator 30; The grid G of N-MOS transistor 42 is electrically connected with the output of signal comparator 30; The source S ground connection of N-MOS transistor 42 forms negative feedback optical monitoring signal circuit thus.And the N-MOS transistor 42 in the feedback circuit 40 also can replace with an analog switch, at this moment, the 6th divider resistance 41 1 ends are electrically connected with the input of analog switch, the other end is electrically connected with the reverse input end of signal comparator 30, the output of signal comparator 30 is electrically connected the control end of analog switch, this analoging switch output end ground connection.The operation principle of above-mentioned optical monitoring signal circuit is as follows: first divider resistance 21 of sampled signal treatment circuit 20 and second divider resistance 22 constitute forward dividing potential drop Vin+ at the positive input of signal comparator 30, reduction makes signal comparator 30 output low level when the ONU optical module is not luminous by the sampled level that sampling resistor 10 obtains.Because there is the hangover of a long period in the MD pin level of some laser driver in the decline process, second divider resistance 22 can be accelerated the decrease speed of this level, helps signal comparator 30 output low levels when unglazed signal condition.The 4th divider resistance 24 and the 5th dividing potential drop 25 have the clamped level A point of formation at the reverse input end of signal comparator 30, utilize the 3rd divider resistance 23 and the MD pin level of laser driver to constitute the reference level Vin-that dividing potential drop forms the reverse input end of signal comparator 30 again.When signal comparator 30 output low levels (TX-SD=0), N-MOS transistor 42 ends, and feedback circuit 40 can not act on the reference level Vin-of the reverse input end of signal comparator 30; When signal comparator 30 output high level (TX-SD=1), 42 conductings of N-MOS transistor, the 6th divider resistance 41 conducting over the ground drags down the A level point, thereby reduces the reference level Vin-of the reverse input end of signal comparator 30.

Positive feedback formula optical monitoring signal circuit as shown in Figure 3, this circuit and negative feedback optical monitoring signal circuit contrast shown in Figure 2, except the input connection of feedback circuit and signal comparator 30 was different, remaining circuit was all identical with operation principle, no longer is repeated in this description.Feedback circuit in this positive feedback formula optical monitoring signal circuit is connected between the output of signal comparator 30 and the positive input by the 7th divider resistance 43 and constitutes.When signal comparator 30 outputs were low level (TX-SD=0), second divider resistance 22 was in parallel with the 7th divider resistance 43, with the positive input level of degrade signal comparator 30 more; When signal comparator 30 was output as high level (TX-SD=1), its positive input improved level by the 7th divider resistance 43.

Claims

1, a kind of optical monitoring signal circuit of GPON ONU module, it is characterized in that, comprise: a sampling resistor (10), one sampled signal treatment circuit (20), one signal comparator (30) and a feedback circuit (40), described sampling resistor (10) is connected in laser and monitors between the MD pin of the positive pole of PD and drive circuit for laser, convert the laser back facet current to voltage differential signal and input to described sampled signal treatment circuit (20), form real-time and effective comparative voltage difference signal after treatment and input to signal comparator (30), the output connected system plate of this signal comparator monitoring port TX-SD that transmits, described feedback circuit (40) is connected between the output and input of described signal comparator (30).

2, the optical monitoring signal circuit of GPON ONU module according to claim 1, it is characterized in that, described sampled signal treatment circuit (20) comprising: first divider resistance (21), second divider resistance (22), the 3rd divider resistance (23), the 4th divider resistance (24), the 5th divider resistance (25), first end of first divider resistance (21) is connected with the positive pole that monitors PD, and its second end is electrically connected second divider resistance (22) of an end ground connection and the positive input of signal comparator (30); First end of the 3rd divider resistance (23) is with after the MD pin of described laser driver is connected, and the other end divides three branch roads to connect: first branch road is electrically connected the 4th divider resistance (24) of an end ground connection; Second branch road is electrically connected the 5th divider resistance (25) that an end connects power supply VCC; The 3rd branch road is electrically connected the reverse input end of signal comparator (30).

3, the optical monitoring signal circuit of GPON ONU module according to claim 2, it is characterized in that, described feedback circuit (40) comprises the 6th divider resistance (41) and a N-MOS transistor (42), the 6th divider resistance (41) one ends are electrically connected with the drain D of N-MOS transistor (42), and the other end is electrically connected with the reverse input end of signal comparator (30); The grid G of N-MOS transistor (42) is electrically connected with the output of signal comparator (30); The source S ground connection of N-MOS transistor (42).

4, the optical monitoring signal circuit of GPON ONU module according to claim 2, it is characterized in that, described feedback circuit (40) comprises the 6th divider resistance (41) and an analog switch, the 6th divider resistance (41) one ends are electrically connected with the input of analog switch, the other end is electrically connected with the reverse input end of signal comparator (30), the output of signal comparator (30) is electrically connected the control end of analog switch, this analoging switch output end ground connection.

5, the optical monitoring signal circuit of GPON ONU module according to claim 2 is characterized in that, described feedback circuit (40) is the 7th divider resistance 43, is connected between the output and positive input of described signal comparator (30).

According to the optical monitoring signal circuit of claim 3,4 or 5 described GPON ONU modules, it is characterized in that 6, the general value of described sampling resistor (10) is 1K Ω～2K Ω.