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PX-D7: fastest visible detector available — 7 ps, 60 GHz- D-8ir: fastest 1310/1550 nm detector available — 8 ps, 50 GHz
- DG-15xr: fastest 750-1650 nm detector available, 20 GHz
- AD-10ir: fastest 1310/1550 nm amplified detector available, 40 GHz
- AD-50APDir: highest sensitivity amplified detector available, -29 dBm
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The complete line of D and AD Series high-speed detectors were developed for Newport by Picometrix®, LLC, Ann Arbor, Michigan. Picometrix is dedicated to the development and manufacture of state-of-the art picosecond optoelectronic devices and instrumentation. Clean-pulse™ technology is a trademark of Picometrix. |
* 9 µm, 50 µm and 62.5 µm optical fibers are used—see specifications table.
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Detector Construction |
Newport’s high-speed detectors come in rugged, self-contained, instrument-style cases that can be directly connected to a measurement instrument for high-speed performance or mounted in almost any convenient location.
Unamplified models (D-Series) come with internal battery power (long-life lithium) for greatest flexibility. Amplified models utilize an external wall-mounted power supply (included) that simply plugs into the side of the case.
In all models, a precision, gold-plated microwave module houses the detector element. The module is directly anchored to the exterior housing, and is rigidly integrated with the fiber input and the output connector. The sealed and shielded module is then packaged in a black-anodized housing that contains all the required power conditioning and current monitor circuitry.
Each unit contains internal voltage regulation and a battery monitor (D Series) that lights an LED when batteries need replacement. The current monitor circuit provides a voltage output that is linear with the average photocurrent produced by the detector element. This feature allows the user to monitor exactly how much light is impinging on the detector element by simply connecting it to a standard voltmeter. The PX-D7 case has all the same internal features as the D-Series case, but comes in a slightly smaller design.
All models are internally fiber-coupled with a choice of either FC or ST external fiber connector (specify at time of order). A front panel BNC connector (PX-D7 has a Lemo connector) provides the current monitor output and a top-mounted switch provides easy on/off operation. |
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The Applications Table above can help you identify products best suited to their application. Applications listed are many of the most common "standard" telecom and datacom system definitions, along with the bit-rate they operate at.
The product column calls out those products specifically suited to operate as a system level receiver for the specified bit-rates. In this situation, the bandwidth of the receiver needs to fall in a fairly tight range. Too little bandwidth creates eye-closure problems, and too much bandwidth allows waveform artifacts to induce errors.
These products have been designed to have an electrical bandwidth (in GHz) that is approximately 75-80% of the bit-rate (in Gb/s). This provides the best fidelity in a classic receive application.
For precise system and transmitter characterization to industry standards, we offer "Reference Receiver" options for several products at 2.5 Gb/s and 10 Gb/s bit-rates. These special receivers have their frequency and phase characteristics controlled to precise standards in order to produce a known or "reference" response against which other system components can be measured. These receivers also offer frequency response down to DC in order to enable accurate extinction ratio measurements within the system.
For diagnostic applications, where the user desires to see any artifacts that are present on the signal waveform, we recommend choosing a receiver with at least two to three times the normal receive bandwidth. |
IR and XR Series detectors |
IR and XR D-Series Unamplified Detectors are designed to meet the rigorous standards of the telephone and data communications industry. The product line is targeted to the needs of communication systems developers both at bit-rate speeds as well as diagnostic speeds. As such, they have optimized performance in narrower wavelength bands. Two different wavelength ranges are available, denoted by the suffixes -ir and -xr. The -ir versions are optimized for longer telecom wavelengths in the 950-1650 nm range, while the -xr series offers an extended range of 700-1650 nm, for both telecom and datacom wavelengths in a single unit. The DG-15ir and DG-15xr are frequency domain products for analog, microwave applications that require a flat power bandwidth from DC-20 GHz.
All these communications products are based on proprietary, high-performance PIN photodiode structures that yield maximum speed and sensitivity for each model. In addition, these products have other features such as fiber diameter, optical return loss and risetimes that meet or exceed the specifications set by commercial communications standards for telecom and datacom. Most of the unamplified products are available with either a 1k Ω internal termination for maximum conversion gain (standard), or an optional 50 Ω termination for low reflection (VSWR) applications.
The IR and XR AD-Series Amplified Detectors present the user with the same versatile photodiodes coupled with a transimpedance amplifier for a high conversion gain and superior sensitivity. These products include receivers for the data rates from 2.5 Gb/s to 40 Gb/s enabling them to be used for testing OC-768, OC-192 and OC-48 speed systems at the receiving end of the link. Reference receivers at 2.5 Gb/s and 10 Gb/s are now also available. For uses requiring high-sensitivity two new APDir amplified detectors are available for 10 Gb/s and 12.5 Gb/s applications.
The IR and XR 10 Gb/s and 12.5 Gb/s PIN designs offer proven telecom level reliability with higher than average responsivity. The XR versions provide unprecedented responsivity across the entire 700nm to 1650nm spectrum.
The APDir products utilize an APD design that is novel and has demonstrated world record receiver sensitivities that are now available. These Avalanche Photodiodes provide the detector with internal gain levels that have not been achievable before in conventional designs.
The 40 Gb/s photodiodes also have a patented design that greatly increases responsivity without sacrificing spectral response. They also have extremely low polarization dependent responsivity and proven, telecom level reliability. |
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Detector Impulse Responses |
Time plot for the D-8ir
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Time plot for the D-50ir
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Time plot for the D-15 and D-15ir
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Time plot for the D-70xr
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Time plot for the D-25xr
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Time plot for the D-100 and D-100ir
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Time plot for the D-30 and D-30ir
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Time plot for the AD-200, AD-200ir and AD-200xr
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Frequency Responses |
AD-10ir
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AD-70xr
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AD-40APDir
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AD-180xr
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AD-50ir, AD-50xr, AD-50APDir
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AD-50ir/RR, AD-50xr/RR
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AD-200ir/RR, AD-200xr/RR
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AC vs. DC Output Coupling |
All of our high-speed detector and receiver products are available with DC output coupling which allows the user to make DC and high-speed optical measurements with the same detector or receiver model. If the user desires to make AC-only measurements, we recommend adding an external DC-blocking capacitor to the output of the device. By selecting the capacitor value, the user can choose a low-frequency cut-off point that is best suited to his needs. Your Newport sales-engineer can help with these recommendations.
When DC-coupling to a receiver, the user must be aware of the output DC offset voltage that may be present. Most products have a zero-voltage output offset and pose no problem for output connection. Some receivers, however, do have a DC -level present at the output. This is dictated by the amplifier used in the product and is often tolerated so that DC measurements can be made. For some models, that have a significant DC offset (up to 3 volts), we offer the user an AC-coupled version that integrates the DC-block within the receiver so no extra part needs to be used. With this option, the low-frequency cut-off is limited to about 1 MHz. If you need lower frequency performance, purchase the DC-coupled version and supply your own external DC-block. |
VIS-ir Series Detectors |
VIS-ir D-Series Unamplified Detectors are based on interdigitated MSM type photodiode detector structures that enable use in the widest variety of applications. They have exceptionally broad wavelength sensitivity from 400 to 1700 nm (except the PX-D7) and large (at least 50 µm), multimode fiber-optic inputs.
The MSM detector design is unique in that it can achieve very high speed (up to 60 GHz or 7 ps) with a large 50 µm active area. As a result, the 50 µm optical input fiber makes these products much easier to use than comparable single-mode products. A 50 µm fiber can provide up to 100 times more light gathering capacity than single-mode fibers in certain measurement situations. The multimode fiber also effectively reduces back reflections into single-mode systems because of the large difference in core areas. Detectors with either ST or FC input connector styles are offered. These features, coupled with the full spectral sensitivity of 400-1700 nm make these products a great value for general high-speed research.
VIS-ir AD-Series Amplified Detectors offer the same broad spectral range and large input fibers as their unamplified counterparts, and also include a transimpedance amplification stage that boosts their conversion gain to at least 200 V/W. To effectively minimize parasitics and to shield the amplifier components from outside noise sources, both the detection element and the amplifier are integrated on a common substrate contained in the microwave module. |
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PX-D7
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Impulse Responses |
Research Detectors
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PX-D7 Impulse Response
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D-15 and D-15ir Impulse Response
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D-30 Impulse Response
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D-100 impulse Response
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Time-domain or Frequency-domain? |
Time-domain products employ Clean-pulse™ technology, which assures exceedingly clean pulse responses with minimal ringing or tails. This is highly desirable for all diagnostic applications, especially digital communications, where an exact temporal replica of the signal under study is required. All of our products (except the DG-15ir and DG-15xr) are designed for time-domain applications.
Frequency-domain products (DG-15ir and DG-15xr) are typically well-suited for analog, microwave applications where a flat-frequency response is more desirable than a clean-temporal pulse. Microwave applications typically benefit from this type of frequency response, because the responsivity of the detector essentially remains constant over the entire usable frequency band. As a result of this frequency response shape, the pulse or time-domain performance is compromised resulting in a pulse that rings slightly (see plots and Tutorial). |
Frequency plot for the DG-15ir and DG-15xr
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Termination Options — 1 kΩ or 50 Ω? |
Most unamplified (D-series) products normally come internally terminated at the output with a 1 kΩ resistor. This provides the highest conversion gain when attached to a 50 Ω measuring instrument, such as an oscilloscope or a spectrum analyzer, because virtually all of the detector’s output current is delivered to the 50 Ω load. In many cases, a 1 kΩ termination also enables the cleanest pulse response.
However, there are measurement situations where reflections between the detector and its load need to be minimized. This is especially true in analog, microwave applications, or where very long time-domain signals need to be accurately measured. In these cases, a 50 Ω termination is preferred, in spite of the fact that only half of the output current is made available to the load, thus reducing the conversion gain by 50%.
Several of the unamplified communications detectors are available with a 50 Ω termination option. This option must be requested at time of order.
Note that the 50 Ω termination does affect the pulse and bandwidth performance of the detector by shortening the pulse duration and increasing the bandwidth to some degree. The specifications cited for those products with the termination option are for the 1kΩ version. Contact Newport’s Application Sales Engineers for specific details. |
Frequency Domain Detectors |
The DG-15ir and DG-15xr photodetectors are specifically designed to be analog, frequency-domain detectors for communications applications where a flat frequency response (±1 dB) from DC-20 GHz is required. The DG-15ir is specifically optimized for the 950-1650nm spectral range with single-mode fiber input, while the DG-15xr provides the same DC-20 GHz performance with 700-1650nm spectral coverage and multimode fiber input. These units are also battery powered, and fully self-contained.
Microwave applications typically benefit from this type of frequency response, where the responsivity of the detector must remain constant over the entire usable 20 GHz band. These models have the same basic performance as the D-15ir (29 GHz opt bandwidth) except that the frequency response shape has been flattened to 20 GHz. As a result of this frequency response shape, the pulse or time-domain performance is compromised resulting in a pulse that rings slightly (see plots and application note).
As with all the D-Series communications detectors, the detector element is optimized for maximum responsivity and the optical return loss is better than 30 dB with a single-mode fiber input on the DG-15ir and 14 dB with multimode fiber on the DG-15xr. Output termination is fixed at 50 ohms for low reflection (VSWR) performance. |
Photodiode Technology |
Incorporated into all our products are the latest, patented photodiode designs that offer a higher level of reliability and sensitivity than has ever been achieved before in this industry. |
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