650 and 800 MHz Balanced Optical Receivers

Ideal for FM spectroscopy, absorption spectroscopy, or ellipsometry, these 650 and 800 MHz balanced photoreceivers can make all the difference when you’re trying to see a small signal. They can eliminate the need for lock-in ampliﬁers, enabling you to cancel out laser intensity noise in any experimental setup that produces either a reference signal or balanced optical signals.

Reduces common-mode noise by 25 dB
Large 650-MHz or 800-MHz bandwidth
Three convenient photocurrent-monitor outputs

See All Features

Description	Compatibility	Price
1607-AC-FC 650 and 800 MHz Balanced Optical ReceiversBalanced Fiber-Optic Receiver, Silicon, 320-1000 nm, 650 MHz, FC Connector	UNIVERSAL	$1,960
1607-AC-FS 650 and 800 MHz Balanced Optical ReceiversBalanced Optical Receiver, Silicon, 320-1000 nm, 650 MHz, Free Space	UNIVERSAL	$1,960
1617-AC-FC 650 and 800 MHz Balanced Optical ReceiversBalanced Fiber-Optic Receiver, InGaAs, 900-1700 nm, 800 MHz, FC Connector	UNIVERSAL	$1,960
1617-AC-FS 650 and 800 MHz Balanced Optical ReceiversBalanced Optical Receiver, InGaAs, 900-1700 nm, 800 MHz, Free Space	UNIVERSAL	$1,960

Specifications

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The -FS models feature a free space optical input but otherwise have the same specifications as their corresponding -FC fiber-optic receiver model.

Features

Reduces Common-Mode Noise by 25 dB

The balanced photoreceivers work by subtracting the photocurrent from two well-matched photodetectors. Common-mode noise that is present on both the reference and signal beams (such as laser intensity noise) is cancelled out and doesn’t appear as part of the signal. Any imbalance between the photocurrents generated by the reference and signal photodetectors, whether intentional or unintentional, is amplified and is seen as the signal. This reduces common-mode noise by up to 25 dB so that you can see your signal.

Large Bandwidth

The photodetectors are carefully chosen for their well-matched frequency responses and are mounted at 90° with respect to each other (one on each side of the box versus both on the same panel). This unique packaging allows for closer photodetector spacing and, therefore, high bandwidth performance up to 800 MHz.

Convenient Photocurrent Monitor Outputs

In addition to the RF output, these balanced photoreceivers have three low-frequency monitor outputs. These monitor outputs can be used to help align light onto the photodiodes, perform low frequency diagnostics, and make manually equalizing the power between the signal and reference beams easier. The monitor outputs have SMB connectors, and an SMB-to-BNC cable is provided with the photoreceiver. All three monitor outputs have a transimpedance gain of 10 V/mA. The bandwidth of the I₂ - I₁ output is DC to 15 kHz, and the bandwidth of the I₁ and I₂ outputs is DC to 100 kHz.

Ideal for Balanced Photodetection

Newport's balanced optical receivers are ideal for optical detection applications that require sensitive measurements and increased signal-to-noise. Balanced photodetection is a method that can very effectively cancel common mode noise and detect small signal fluctuations on a large DC signal. Detection methods in the time domain (such as femtosecond ultrasonics and frequency modulation spectroscopy) and frequency domain (like absorption spectroscopy), and coherent heterodyne detection (such as optical coherence tomography) can be substantially improved by using Newport balanced photoreceivers and can allow detection of signals not otherwise possible with other means. For more information, please see our application note A Survey of Methods Using Balanced Photodetection.

Example OCT Imaging System

Measuring Absorption Properties Application

The Model 1607-AC balanced photoreceiver is especially useful in measuring absorption properties. Here, a probe beam is focused onto one of the photodetectors while the other detects a reference beam.