Stanford Research LDC501 – Laser Diode Controller

The Stanford Research Systems LDC501 Laser Diode Controller delivers precision current and temperature control for demanding laser diode applications. It combines a low-noise current source with a high-precision temperature controller, offering bumpless switching between constant current and constant optical power modes. Built-in protection features including adjustable current limits, compliance voltage control, and fast shutdown safeguard laser diodes during operation.

Technical Specifications

• Output range: 0 to 500 mA


• Setpoint resolution: 10 µA


• Accuracy: ±0.01% of full scale


• Output impedance: >1 MΩ (DC)


• Thermal stability: <10 ppm/°C


• Short-term stability (1 hr): <5 ppm full scale


• Long-term stability (24 hr): <15 ppm full scale


• Current noise: 1.5 µA rms to 4.5 µA rms depending on bandwidth selection


• Analog modulation: 0–10 V input, 500 kHz bandwidth (1 MHz in CC mode)


• Digital modulation: TTL compatible, 2 MHz bandwidth


• Photodiode bias: 0 to 5 V, programmable Temperature Controller


• TEC power output: 36 W


• Temperature resolution: 0.001 °C


• Accuracy: 0.01 °C (with calibrated sensor)


• Stability: 0.0005 °C/°C with respect to room temperature


• Supported sensors: Thermistor, RTD, IC sensors


• Auto-tuning: PID loop optimization included

Key Features

• Constant current (CC) and constant optical power (CP) modes with bumpless switching


• Constant temperature (CT) and constant current (CC) modes for TEC control


• Slow start turn-on and fast clamping shutdown


• Adjustable current limits and compliance voltage


• Over-temperature shutdown protection


• TTL trigger input

Interfaces & Integration

• GPIB (IEEE-488), RS-232, and Ethernet remote control


• Nine non-volatile configuration save/recall slots


• 19″ rack-mount, 2U form factor


• 100–240 V AC, 50/60 Hz; supports 100V, 120V, 220V, 240V nominal operation


• Weight: 8.5 lbs (3.9 kg)