Sanwa OPM37LAN Optical Power Meter

The Sanwa OPM37LAN is a portable optical power meter engineered for precise measurement across fiber optic LAN networks and field installations. Built around an SI photodiode sensor, it delivers absolute and relative power measurements in both dBm and watts, with 8 automatic measurement ranges spanning 1 nW to −20.00 mW. The instrument supports five selectable wavelengths - 650 nm, 780 nm, 800 nm, 850 nm, and 880 nm - making it compatible with standard telecommunications and local area network deployments.

A 4-digit display provides real-time readings at 3.33 samples per second, while a 20-data sequential averaging function reduces noise in fluctuating signal environments. Measurement accuracy is ±5.0% with 0.01 dB resolution. RS-232C serial output (9600 bps, 8 data bits, no parity, 1 stop bit, hardware flow control) enables direct PC data logging and analysis.

Powered by a 006P alkaline battery or optional AC adapter (AD-30), the meter includes a 2-meter sensor extension cord and interchangeable optical connector adapters. Additional connector types

SC, unidirectional TOSLINK, and duplex TOSLINK - are available as optional accessories, allowing rapid field reconfiguration. Operating range is 18°C to 25°C at 80% RH maximum; input power is capped at 20 mW to protect the photodiode from overload damage.

Technical Specifications

• Measuring Range: 1 nW to −20.00 mW


• Accuracy: ±5.0%


• Resolution: 0.01 dB / ±0.01%


• Wavelengths: 650 nm, 780 nm, 800 nm, 850 nm, 880 nm (selectable)


• Optical Sensor: SI photodiode


• Display: 4-digit


• Measurement Ranges: 8 automatic


• Sampling Rate: 3.33 Hz


• Operating Temperature: 18°C to 25°C, 80% RH maximum


• Maximum Input Power: 20 mW

Key Features

• dBm and watt measurement modes


• Relative value measurement (dBm(REL) and W(REL))


• 20-data sequential averaging


• RS-232C interface with continuous ASCII output


• Interchangeable optical connector adapters (FC standard; SC, TOSLINK variants available)


• Dual power: 006P battery or AC adapter

Typical Applications

• Fiber optic network commissioning and verification


• LAN installation and troubleshooting


• Field power level auditing and documentation


• Connector and splice loss measurement via relative mode

Compatibility & Integration RS-232C serial communication enables direct integration with PC-based measurement systems and automated data logging platforms. Connector adapter options support FC, SC, and TOSLINK interface standards. Sensor extension cord (2 meters) permits remote probe placement in confined or elevated installations.