Amplified photodetector

To achieve low-noise readout and high-gain amplification of weak signals, and to restore optical signals with minimal distortion, Dimension-Labs has launched the DL-PDA series of amplified photodetector modules. The spectral response range covers the full spectrum from ultraviolet to long-wave infrared (0.2 μm ~ 10.6 μm). These modules have a built-in low-noise transimpedance amplifier (TIA) or a low-noise TIA followed by a voltage amplifier, enabling effective detection and amplification of weak optical signals with a maximum detectable bandwidth of 50 GHz and a minimum detectable power of -75 dBm. We offer versions with fixed gain and eight adjustable gain levels. The fixed-gain version features fixed bandwidth and total transimpedance gain, while the adjustable-gain version provides eight gain settings (0 ~ 70 dB with 10 dB steps). The entire module adopts an innovative USB (Type-C) power interface, and the 5V USB power supply makes it more convenient to use, making it suitable for industrial applications and scientific research in numerous fields.

▶▶Advantages

• Wavelength coverage: 200nm - 12μm (multiple detection materials available, including Si, Ge, InGaAs, MCT, etc.)
• High gain, high sensitivity (minimum detectable: -75dBm) ▶ 8-level adjustable gain (0 - 70dB)
• Optional photosensitive area diameter (80μm - 10mm)
• USB (Type-C) power interface / SMA data interface
• Free switching between spatial light and fiber optic light
• Flexible compatibility with various accessories such as rods, cage systems, and sleeves
• Exquisite and compact design, suitable for a wide range of applications

▶▶Product Applications

• High-speed optical pulse detection
• LiDAR (Light Detection and Ranging)
• Brillouin fiber optic sensing system
• Optical Coherence Tomography (OCT)
• Optical delay measurement
• THz & spectroscopy measurement

▶▶Wavelength coverage of 0.2μm - 12μm, offering a wider range of options

The DL-PDA Series photodetectors, meticulously developed by Dimension-Labs, offer spectral coverage spanning ultraviolet, visible, near-infrared, mid- and long-infrared regions. These detectors incorporate high-quality silicon (Si)-based photodiodes (PDs) specifically engineered for optical signal detection within the 200nm-1100nm wavelength range. Indium gallium arsenide (InGaAs) photodetectors effectively address detection needs from 800nm to 1700nm, while extended-wavelength InGaAs variants cover 900nm-2600nm. Additionally, mercury cadmium telluride (MCT) photodetectors provide coverage from 2.6μm to 10μm, offering an extensive selection of detection solutions for numerous scientific research and industrial photoelectric conversion applications.

▶▶High sensitivity / high gain / low noise, matching multiple requirements

Dimension-Labs' exclusively developed DL-PDA series photodetectors are equipped with a built-in transimpedance amplifier (TIA) circuit featuring low noise and high gain, which can convert and amplify the photocurrent through the TIA with a gain range of (5×10³ V/W) to (2.0×10⁶ V/W). Even under such high gain conditions, it can restore optical signals with minimal distortion, significantly enhancing the detection capability for weak optical signals. The detection sensitivity can reach -75 dBm, and the noise of all gain levels is as low as 3.0 mV or below.

▶▶Free switching between spatial light and fiber optic light, enabling multi-purpose use with one device

Dimension-Labs has made innovative designs on the appearance of the DL-PDA series photodetectors. The housing of the free-space optical input port features SM1 external threads and SM05 internal threads, and includes a detachable SM1 internal thread adapter (adapter and retainer ring). To position the diode as close as possible to the cage plate and facilitate accurate detection by beam divergence devices, the threads of the detector interface can be directly mounted on the cage plate and are also compatible with cage systems. This enables it to be applicable not only to free-space light detection, but also to fiber optic light detection through the combination of fiber coupling flanges.

▶▶Flexible installation with multiple components, meeting the setup requirements of various scenarios

In terms of accessories, the DL-PDA series photodetectors can be paired with lens sleeves/cage plates of SM1/SM05 calibers, which are perfectly compatible with cage optical systems. Additionally, in the attenuation solution for high-power laser detection, they can be used with neutral density filters, featuring simple operation and easy installation. Moreover, they are also perfectly adapted to the interface of Dimension's Archimedean integrating sphere, enabling fiber optic light users to complete (relevant operations).

▶▶Eight adjustable gain levels, maximizing adaptability to multi-level applications

With flexible usability as its core design concept, the adjustable-gain photodetector features multiple freely switchable gain levels, offering eight gain settings (0–70 dB with 10 dB steps). The multi-level adjustment ensures greater convenience in use, making it suitable for both industrial applications and scientific research across various fields. Customers can select appropriate gain and bandwidth based on their specific application scenarios, which maximizes the fulfillment of their application needs and significantly enhances practicality.

▶▶Compact and Exquisite Design, Versatile for Diverse Applications

The housing dimensions are merely 65 mm × 55 mm × 23 mm. This compact size enables the detector to be placed in most parts of optical systems. It addresses the issue of embedding detectors in small and complex systems as much as possible, thereby expanding the range of applicable scenarios.

The on/off status and color of the indicator light indicate the operating state of the DL-PDA series detectors. When the power is connected and the switch is turned on, the LED indicator for normal startup will light up green. If the gain is too high, the LED will turn red; in this case, turn the knob to reduce the gain until the LED turns green, allowing the detector to work normally.

▶▶Multiple Photosensitive Area Sizes Available, High Compatibility

The DL-PDA Series photodetectors from Dimension-Labs incorporate detection chips with various photosensitive area sizes, ranging from 80μm to 10mm in diameter. This high compatibility ensures maximum flexibility to meet diverse customer requirements. Additionally, we offer customized photodetectors tailored to specific applications, providing bespoke solutions for unique photosensitive area specifications.

▶▶More convenient USB power supply / SMA data interface

Dimension-Labs has revolutionarily introduced a USB power interface. The DL-PDA series photodetectors are powered via a USB-Type C power interface, and are equipped with a USB-Type C power cable and an SMA-to-BNC adapter cable. This allows users to conveniently power the device directly using a mobile phone charger and read signals on an oscilloscope, enhancing its universality for both research and industrial users.

Application Scenarios

Dimension-Labs offers a comprehensive range of PDA amplified photodetectors, which can cover most scenarios requiring low-noise and high-gain restoration of weak signals, and are widely applied in medical, military, and civil fields.

▶▶Measurement of high-repetition-rate laser pulse sequences

In lidar and laser pulse measurements, there is a need to measure laser pulse sequences. Continuous lasers generate pulsed lasers through modulation, or semiconductor laser diodes produce pulsed lasers through circuit RF coding. The detector receives the optical signal and converts it into an electrical signal. The high-bandwidth design of Dimension-Labs' PDA series detectors enhances the ability to measure the repetition frequency of corresponding pulsed lasers, enabling the acquisition of complete information about laser coding or modulation.

▶▶Photoelectric detection compatible with cage systems

Cage optical systems offer advantages of high linearity and high parallelism. In precision optical measurements, common optical posts may make it difficult to maintain high coaxiality of optical components, leading to inaccurate measurement results. To address this issue, Dimension-Labs' DL-PDA series amplified photodetectors feature an SM1 external thread design at the light inlet. When used with a lens sleeve, the detector can be embedded into the cage system, ensuring the coaxiality of the experiment and reducing the impact of angular deviation on measurements for users.

▶▶Lidar echo signal detection

In application scenarios involving long-distance infrared imaging, due to the relatively long detection distance, the echo power is low. This requires the use of a high-gain amplification circuit to effectively respond to weak signals, as well as a telescope with a large-aperture objective lens to expand the photosensitive aperture. Dimension-Labs' PDA series, featuring high gain, low noise, and high bandwidth, can flexibly work with lens sleeves to transmit the light collected by the telescope to the photosensitive surface of the PDA detector. Through the amplification circuit, it makes the detection of echo signals easier.

▶▶Laser power monitoring

In scientific research and industrial projects, monitoring laser power is crucial for system performance and project development. Practical applications include experimental optical path system setup, judgment of laser coupling efficiency, component reflectance detection, and verification of silicon optical chip coupling systems. Dimension-Labs' self-developed high-performance photodetectors can effectively capture optical signals with their ultra-high sensitivity and resolution. They can quickly respond to detected laser wavelengths and convert them into electrical signals, enabling high-precision detection. Additionally, when used with an optical integrating sphere, they can effectively extend the upper limit of laser power detection, reduce R & D costs, and improve project R & D efficiency.